Publications

loss of epidermal growth factor receptors and release of transforming growth factors do not correlate with sarcoma virus-transformation in clonally-related nih/3t3-derived cell lines.	transformation of nih/3t3 cells by kirsten murine sarcoma virus (msv) caused a dramatic reduction in the number of cell-surface receptors for epidermal growth factor (egf). however, the number of egf receptors remained at a very low level in a non-tumourigenic revertant cell line isolated from the virus-transformed cells, indicating that an increase in egf receptors is not a requirement for the phenotypic reversion of kirsten msv-transformed 3t3 cells. serum-free conditioned medium from normal a ...	1985	2994627
autoregulation plus upstream positive and negative control regions associated with transcriptional activation of the mouse p1(450) gene.	2,3,7,8-tetrachlorodibenzo-p-dioxin (tcdd) is known to interact with a cytosolic receptor and, in turn, activate transcription of the mouse p1(450) gene. various lengths of dna upstream of the p1(450) gene were inserted into the psv0-cat expression vector, with and without addition of the harvey murine sarcoma virus (ha-msv) 72-bp repeat enhancer element. the constructs were cotransfected with psv2-neo into mouse hepatoma wild-type cells and two variant cell lines. one variant is believed to res ...	1985	2997746
presence of circulating antibodies against gag-gene mulv proteins in patients with autoimmune connective tissue disorders.	an immunoblotting procedure using viral proteins from purified murine sarcoma virus or msv-(mlv) has been developed to characterize antiviral antibodies in sera from patients with autoimmune connective tissue disorders. fifty-eight sera with anti-sm, anti-rnp, anti-ss-b (la), and other undefined specificities were found to react with several major viral polypeptide bands. most of them corresponded to gag-gene-encoded products: pr65gag, p40gag, p30, p15, p12 and p10. other bands with molecular we ...	1985	2998055
detection and preliminary characterization of a transmissible agent inducing autoantibody against golgi-antigen.	a transmissible agent inducing autoantibody has been found in association with tumours induced in stu mice with the progressor strain of moloney sarcoma virus (mo-msv). the activity of the agent detectable in serum from tumour-bearing hosts was expressed by development of autoantibody against golgi-associated evolutionary conserved antigen (weiland et al. 1984). this agent was tentatively designated 'agia', anti-golgi inducing agent, on account of its most remarkable biological activity. concomi ...	1985	2998658
analysis of the cellular proto-oncogene mht/raf: relationship to the 5' sequences of v-mht in avian carcinoma virus mh2 and v-raf in murine sarcoma virus 3611.	the avian carcinoma virus mh2 contains a hybrid gene delta gag-mht with a contiguous open reading frame of 2682 base pairs as well as v-myc and avian helper virus-related sequences. delta gag is a partial retroviral core protein gene while v-mht and v-myc are cell-drived sequences. the v-mht sequence can be divided into two regions: the v-raf-related region at its 3' end contains 969 nucleotides which are 94% related as amino acid sequence to the onc-specific v-raf sequence of murine sarcoma vir ...	1985	3002017
abelson virus drives the differentiation of harvey virus-infected erythroid cells.	abelson murine leukemia virus (a-mulv) and harvey murine sarcoma virus (ha-msv) are retroviruses carrying unrelated onc genes. however, both of these viruses are capable of stimulating the growth and differentiation of erythroid precursor cells; the target cells for both appear at the same time during fetal development and follow a similar pattern throughout ontogeny. in addition, the colonies induced by each virus are morphologically similar and synthesize the adult form of hemoglobin. however, ...	1986	3002634
homologous recognition of a promoter domain common to the msv ltr and the hsv tk gene.	we have partially purified, from rat liver, a nuclear protein fraction with sequence-specific affinity to a promoter domain shared by the herpesvirus tk gene and the moloney murine sarcoma virus ltr. for both promoters, the protein-binding domain occurs roughly 80 bp upstream of the mrna cap site and harbors the pentanucleotide sequence 5'-ccaat-3'. the msv ltr pentanucleotide occurs on the coding strand in an orientation pointing toward the retroviral transcription unit. the hsv tk pentanucleot ...	1986	3004739
nucleotide sequence of exon i of the rat c-k-ras gene.	we have isolated a dna fragment containing exon i of rat cellular proto-oncogene of k-ras and sequenced the exon i. the obtained sequence was compared with that of the corresponding region in viral oncogene of kirsten strain of murine sarcoma virus (ki-msv). the results showed that the exon i sequences of cellular k-ras genes in rat and human cells could encode the same amino acid sequence, while the viral k-ras gene could code for two different amino acids corresponding to the 12th and 37th pos ...	1986	3009041
rescue of presumptive viral information from human cells by a helper oncovirus.	we have attempted to rescue presumptive human endogenous retrovirus(es) by using a competent animal oncovirus as a helper. human melanoma cells (line hmb2) were fused, using polyethylene glycol, with mouse nih-3t3 cells which had been infected and transformed by the harvey murine leukaemia and sarcoma virus complex (mlv and msv). the heteropolykaryons obtained were co-cultivated with fresh nih-3t3 cells; filtered (millipore 0.22 micron) medium from these was used to infect further nih-3t3 cells. ...	1986	3016151
31p nmr spectra of rodent and avian fibroblasts transformed by rous or kirsten sarcoma viruses.	31p nmr spectra of normal rodent and avian fibroblasts were compared to those of the same cells transformed either by the rous sarcoma virus (rsv) or by the kirsten sarcoma virus (ki-msv). under physiological conditions, the spectra of living or perchloric acid extracted chicken embryo fibroblasts, rat cell line fr3t3 and mouse cell line c127 did not differ from those of their counterparts transformed by rsv or ki-msv. however, in the case of fr3t3 cells, on shifting from 37 degrees c to 20 degr ...	1986	3017336
class ii histocompatibility antigen expression in human melanocytes transformed by harvey murine sarcoma virus (ha-msv) and kirsten msv retroviruses.	human melanocytes infected with ki-msv or ha-msv, but not amphotropic mulv, undergo a series of transformation-related changes that are characteristic of malignant melanoma. these are (a) expression of ia antigens, in particular dp, dq, and dr class ii histocompatibility gene products, (b) a transformed morphology and ability to grow in soft agar, and (c) a 5-10-fold increase in the cell surface expression of gd3 ganglioside. however, other characteristics of melanoma, such as independence from ...	1986	2430046
an activated harvey ras oncogene produces benign tumours on mouse epidermal tissue.	studies of the mutagenic action required for specific chemicals to produce benign or malignant tumours suggest that in mouse skin at least two genetic events occur before carcinoma formation. the isolation of an activated form of the c-rash gene from skin papillomas has provided evidence that this gene may be a target for the first mutation, which could constitute the initiating mutation in skin carcinogenesis. in vitro studies indicate that the v-rash gene of harvey murine sarcoma virus (ha-msv ...	1986	2430189
opposing effects of the interferon inducer, avridine: enhancement or suppression of tumor growth depending on treatment regimen.	tumor growth and regression was studied in c57bl/6j mice injected with moloney sarcoma virus (msv) and treated with the interferon (ifn)-inducing drug, avridine. avridine decreased the persistence of tumors when given one or five days after virus, but shortened the prepatent period and increased persistence if given one day prior to virus. additional studies were undertaken to study the role that serum interferon and natural killer (nk) cell activity might have in this phenomenon. interferon lev ...	1986	2432025
sequence homology between the coat proteins of dna and rna plant viruses.	the coat proteins of the leafhopper transmitted gemini viruses, viz., maize streak virus and wheat dwarf virus that contain a single circle of dna in their genomes are shown to bear good amino acid sequence homology with the coat protein of an rna plant virus, the satellite tobacco necrosis virus. it is suggested that for icosahedral assemblage, the coat protein architecture transcends genomic preferences.	1986	3947330
multistep process of neoplastic transformation of normal human fibroblasts by 60co gamma rays and harvey sarcoma viruses.	as reported previously (namba et al., 1985), normal human fibroblasts were transformed by 60co gamma-ray irradiation into immortal cells with abnormal karyotypes. these transformed cells (kmst-6), however, showed a low cloning efficiency in soft agar and no transplantability. however, upon treatment with harvey murine sarcoma virus (ha-msv), the cells acquired elevated clonability in soft agar and transplantability in nude mice. ha-msv alone, however, did not convert normal human fibroblasts int ...	1986	3949423
functions of the mos oncogene family and associated gene products.	the mos oncogene present in moloney murine sarcoma virus is one of the oldest known oncogenes, yet the identification of its biochemical function both in transformation and as a cellular proto-oncogene has been elusive. only recently have low levels of c-mos transcripts been detected in a specific group of mouse tissues. the c-mos gene is implicated in tumorigenicity by its activation by the insertion of the intracisternal a particle genome in a mouse plasmacytoma. the murine c-mos gene is capab ...	1986	2946405
interaction between raf and myc oncogenes in transformation in vivo and in vitro.	3611 msv, a raf-oncogene-transducing murine retrovirus, induces fibrosarcomas and erythroid hyperplasia in newborn mice after a latency of 4-8 wk. in contrast, new recombinant murine retroviruses carrying the myc oncogene (j-3, j-5 construct viruses) do not induce tumors before greater than 9 wk. a combination of both oncogenes in an infectious murine retrovirus (j-2) induces hematopoietic neoplasms in addition to less prominent fibrosarcomas and pancreatic adenocarcinoma 1-3 wk after inoculatio ...	1986	3084503
nuclear factors binding specific sequences within the immunoglobulin enhancer interact differentially with other enhancer elements.	the mouse immunoglobulin heavy chain (igh) enhancer represents a cis essential control element that confers lymphoid-specific expression. based on in vivo and in vitro competition experiments, as well as on in vivo dimethylsulfate (dms) protection experiments, it has been inferred that cellular factors interact in trans with igh enhancer sequences. in addition, transcription is stimulated in vitro by up to one order of magnitude in the presence of igh enhancer sequences on an appropriate templat ...	1986	3102227
t-cell immunity to murine moloney sarcoma virus-induced tumours: l3t4+ t cells are necessary for resistance to primary sarcoma growth, but lyt-2+ t cells are required for resistance to secondary tumour cell challenge.	experimental protocols have been devised to deliniate the importance of t-cell subsets in immunity to moloney sarcoma virus-induced tumours using the surface antigens l3t4 and lyt-2 as markers of helper and cytotoxic cells, respectively. because the monoclonal antibodies used have been shown to deplete t-cell subsets in vivo, we have been able to study the role of l3t4+ and lyt-2+ t cells in the primary response to msv for the first time. the results clearly show that l3t4+ t cells are the most ...	1987	2956180
myosin isoform expression in rat rhabdomyosarcoma induced by moloney murine sarcoma virus.	myosin isoform expression was analyzed in experimental rhabdomyosarcoma (rms) using monoclonal antibodies (mabs) and immunofluorescence techniques. tumors induced by inoculating newborn rats with moloney murine sarcoma virus (mo-msv) were examined 30-90 days after birth. nine tumors and two lymph node metastases were studied by direct, indirect, and double immunofluorescence assays using a panel of five anti-myosin mabs. the mab bf-45 was specifically reactive with embryonic myosin heavy chain ( ...	1987	3305517
defects in lens fiber differentiation are linked to c-mos overexpression in transgenic mice.	we describe three strains of transgenic mice derived by embryo microinjection of dna consisting of a long terminal repeat (ltr) of moloney murine sarcoma virus (mo-msv) linked to the murine c-mos coding sequences. southern analysis of the genomic dna of these strains suggested that in each case the transgene had integrated at a different chromosomal location. the strains were characterized by dominant changes in secondary lens fiber differentiation. shortly after birth, insufficient elongation o ...	1987	3322940
structure and replication of geminivirus genomes.	the geminiviruses are a group of plant viruses containing single-stranded (ss) dna in particles comprising two quasi-icosahedral units. some are transmitted by whiteflies, others by leafhoppers. comparisons were made of the genome organization and expression of cassava latent virus (clv) and maize streak virus (msv) and beet curly top virus (bctv), each with distinct host range and insect vector species characteristics. from these studies, several indications as to the replication mechanism(s) a ...	1987	3503890
the nucleotide sequence of a geminivirus from digitaria sanguinalis.	the encapsidated single-stranded circular dna of a geminivirus isolated from digitaria sanguinalis has been sequenced. the data obtained are consistent with there being one dna circle of 2701 nucleotides. comparison of the nucleotide sequence with those of maize streak virus (msv) and wheat dwarf virus showed 64 and 47% dna homology, respectively. the sequence has four potential coding regions for proteins of greater than 10 kda, two in the viral (+) sense and two in the complementary (-) sense. ...	1987	3672928
retinoic acid modulates attachment of mouse fibroblasts to laminin substrates.	the effect of retinoic acid treatment on cell attachment to plastic substrates precoated with fibronectin, gelatin, laminin, and type iv collagen was investigated. both retinoic acid-treated and control cells attached efficiently to fibronectin or gelatin substrates without any significant difference. in contrast, retinoic acid-treated cells attached to laminin or type iv collagen substrates, while control cells showed little or no attachment. the minimal effective concentration of retinoic acid ...	1987	3691670
temporary inhibition of moloney-murine sarcoma virus (m-msv) induced-tumours by adoptive transfer of ricin-treated t-lymphocytes.	the potential use of tumour-specific t-lymphocytes loaded with ricin in cell targeting experiments was investigated. moloney-murine sarcoma virus (m-msv)-specific t-lymphocytes, obtained in mass mixed leucocyte-tumour cell culture (mltc) and a m-msv-specific cytotoxic t-lymphocyte (ctl) clone, were incubated with 125i-labelled ricin in order to evaluate toxin uptake and release. the internalized ricin (4.5 x 10(-17) mol and 6.5 x 10(-17) mol per 10(2) mltc and ctl clone cells, respectively) was ...	1987	2437947
characterization of hyaluronate binding proteins isolated from 3t3 and murine sarcoma virus transformed 3t3 cells.	a hyaluronic acid binding fraction was purified from the supernatant media of both 3t3 and murine sarcoma virus (msv) transformed 3t3 cultures by hyaluronate and immunoaffinity chromatography. sodium dodecyl sulfate-polyacrylamide gel electrophoresis resolved the hyaluronate affinity-purified fraction into three major protein bands of estimated molecular weight (mr,e) 70k, 66k, and 56k which contained hyaluronate binding activity and which were termed hyaluronate binding proteins (habp). hyaluro ...	1987	2440472
murine retroviruses control class i major histocompatibility antigen gene expression via a trans effect at the transcriptional level.	moloney murine leukemia virus (m-mulv) and moloney murine sarcoma virus (m-msv) exert a regulatory effect on the class i genes of the murine major histocompatibility complex (mhc). we have previously shown that m-mulv infection of mouse fibroblasts results in a substantial increase in cell surface expression of h-2k, h-2d, and h-2l proteins, whereas m-msv, upon coinfection of the same cells, is apparently able to override the mulv-induced increase in h-2 expression. as a result of this modulatio ...	1987	2441241
changes in cellular gene expression in rat thyroid epithelial cells transformed by the kirsten murine sarcoma virus.	we have exploited a recently characterized system of rat thyroid epithelial cells transformed by the wild-type (wt) and a temperature-sensitive (ts) mutant strain of the kirsten murine sarcoma virus (ki-msv) in order to study the effects of the k-ras oncogene on the gene expression of differentiated thyroid epithelial cells. by using cdnas isolated from normal thyroid glands as probes, we were able to identify three sets of cellular sequences whose expression is influenced by the v-k-ras oncogen ...	1987	2442021
the interaction of retrovirus and chemical carcinogen in experimental colon carcinogenesis.	the isolation and characterization of oncogenes from human colon cancer and the recognition of their homology with the ras gene of the harvey and kirsten strain of murine sarcoma virus (msv) led us to investigate the effect of exogenous msv on 1,2 dimethylhydrazine (dmh)-induced colon carcinoma in rats. dmh, 20 mg base/kg, was injected weekly for 10 weeks into sprague-dawley rats. the moloney murine sarcoma virus (msv-m) was injected (200 focus-forming units) intraperitoneally into 15 rats 48 ho ...	1987	3027910
functional activity in vivo of effector t cell populations. iii. protection against moloney murine sarcoma virus (m-msv)-induced tumors in t cell deficient mice by the adoptive transfer of a m-msv-specific cytolytic t lymphocyte clone.	the functional activity of moloney murine sarcoma virus (m-msv)-specific t lymphocytes in vivo was assayed by the i.v. injection of virus-specific t lymphocytes into t cell-deficient "b mice". virus-specific t lymphocytes generated in mixed lymphocyte tumor cell cultures were transferred i.v. into syngeneic "b mice" injected simultaneously at a distant site with the virus. these experiments indicated that a low dose (1 x 10(6) cultured cells) of infused lymphocytes can afford protection. to defi ...	1987	3030766
structure and expression of mos sequences in spontaneous and moloney murine sarcoma virus-induced yolk sac carcinomas in rats.	facilitation of yolk-sac carcinoma (ysca) development in fetectomized rats by the moloney murine sarcoma virus/murine leukemia virus (mo-msv/mlv) complex was found to be closely associated with the presence of mo-msv sequences in the genomes of the ysca cells. the virus-induced yscas consisted of cells of mono- or oligoclonal origin which always contained in their genomes at least i randomly integrated mo-msv provirus. in yscas which developed in the absence of virus, no rearrangement or amplifi ...	1987	3030942
biologic and molecular characterization of two newly isolated ras-containing murine leukemia viruses.	a murine sarcoma virus (msv) was recovered from an (nfs x ns.c58v-1) f1 mouse which developed splenic sarcoma and erythroleukemia 6 months after inoculation with a mink cell focus-inducing murine leukemia virus (mulv) isolated from an nfs mouse infected with a wild mouse ecotropic mulv. the msv, designated ns.c58 msv-1, induced foci of transformation in mouse and rat fibroblasts, and inoculation of mice of various strains 2 weeks of age or younger resulted in erythroleukemia and sarcomatous lesi ...	1987	3035212
mouse xenotropic viruses can inhibit cell transformation.	mammalian type c retroviruses can be detected by their induction of foci of cell transformation in s+i - cells. we have noted that certain subtypes of the mouse xenotropic type c retrovirus (mulv) inhibit this cell alteration. this inhibition, associated with intact virions, is irreversible and gives the infected cells a phenotype of uninfected cells. in comparison to the transformed cells, the inhibited cultures showed primarily a decrease in murine sarcoma virus (msv) progeny production concom ...	1987	2820140
optimizing gene expression in bpv-transformed cells: effects of cell type on enhancer/promoter interaction.	we have compared several combinations of enhancers and promoters in expressing the chloramphenicol acetyl transferase gene in transient assays, in mouse c127, the most widely used host cell for the bovine papilloma virus (bpv) expression vector. of the various combinations tested, the unit comprised of the sv40 enhancer and adenovirus type 2 major late promoter (mlp) was the most active in bpv transformed c127 cells. we further demonstrate that untransformed and bpv transformed c127 cells respon ...	1987	2821493
human p45ia1 upstream regulatory sequences expressing the chloramphenicol acetyltransferase gene. effect of ha-msv enhancer and comparison of transient with stable transformation assays.	upstream sequences of the human p450ia1 gene were inserted into a promoterless expression vector (psvo-cat) containing the chloramphenicol acetyltransferase (cat) gene, with and without the harvey murine sarcoma virus (ha-msv) core enhancer, and either plasmid was transfected into human breast carcinoma mcf-7 and mda-231 and mouse hepatoma hepa-1 cell lines. in most instances constitutive and inducible cat activities in the transient cat expression assay were similar (within 3-fold) to those in ...	1987	2825673
synthesis of specific transformation-associated proteins (taps) in two rat cell lines is closely related to the expression of the v-mos gene product of moloney murine sarcoma virus (mo-msv).	the 6m2 cell line was established by transformation of normal rat kidney cells with the ts110 mutant of moloney murine sarcoma virus (mo-msv). p85gag-mos was found to be the only known viral-transforming protein in this cell system. previously, we described the detection in 6m2 cells of rat-specific transformation-associated proteins (taps) using a monoclonal antibody (mc). in this study, we used mc to investigate further the expression of taps at different temperatures and the time course of tu ...	1987	2828268
reduced protein kinase c activity in a ras-resistant cell line derived from ki-msv transformed cells.	we have examined phosphatidylinositol turnover and c-kinase distribution in a flat cellular ras-resistant cell line (c11) derived from kirsten murine sarcoma virus (ki-msv) transformed nih/3t3 cells (dt). this cell type has been shown to express high levels of the p21 ki-ras gene product yet is resistant to the transforming effects of this protein. our data indicate that c11 cells have reduced levels of total c-kinase activity when compared to nih/3t3 cells and do not retain the ability to phosp ...	1987	2830575
the in vitro and in vivo anti-retrovirus activity, and intracellular metabolism of 3'-azido-2',3'-dideoxythymidine and 2',3'-dideoxycytidine are highly dependent on the cell species.	cell lines derived from different species show striking differences in their sensitivity to the cytostatic and anti-retrovirus activity, as well as the intracellular metabolism, of 3'-azido-2',3'-dideoxythymidine (azddthd) and 2',3'-dideoxycytidine (ddcyd). azddthd and ddcyd are considerably more cytostatic to human (i.e. raji, molt/4f, ath8) cell lines than murine (i.e. l1210) cells. the intracellular levels of azddthd 5'-triphosphate and ddcyd 5'-triphosphate formed do not seem related to the ...	1988	2830886
increment of dna topoisomerases in chemically and virally transformed cells.	the activities of topoisomerases i and ii were assayed in subcellular extracts obtained from nontumorigenic balb/c 3t3 a31 and normal rat kidney (nrk) cell lines and from the same cells transformed by benzo[a]pyrene (bp-a31), moloney (m-msv-a31) and kirsten (k-a31) sarcoma viruses, and simian virus 40 (sv-nrk). the enzymatic activity of topoisomerase i was monitored by the relaxation of negatively supercoiled pbr322 dna and by the formation of covalent complexes between 32p-labeled dna and topoi ...	1988	2831071
kirsten murine sarcoma virus abolishes interferon gamma-induced class ii but not class i major histocompatibility antigen expression in a murine fibroblast line.	the effect of infecting fibroblasts with kirsten murine sarcoma virus/murine leukemia virus (ki-msv/mlv) on constitutive and ifn-gamma-induced h-2 antigen expression was investigated. the fibroblasts used were two established cell lines (c3h10t1/2 and balb/c3t3) and fresh embryo fibroblasts from c3h mice. class i antigens were expressed constitutively by balb/c3t3; infection with mlv, msv or the two together had little effect on this constitutive expression. class i antigens (h-2k, h-2d) were st ...	1988	2831293
dibutyryl camp inhibits expression of transformation-related properties in kirsten murine sarcoma virus transformed balb/c-3t3 cells despite continued presence of p21v-ki-ras.	we studied the effects of simultaneous treatment with 0.1 mm n6, o2'-dibutyryl camp (dbcamp) and 1 mm theophylline on several transformation-specific properties and on levels of the kirsten murine sarcoma virus (ki-msv) transforming gene product p21v-ki-ras, in a ki-msv-transformed mouse cell line (balb/c-3t3, clone a31; ka31). the rate of logarithmic growth, cell motility, and final saturation density were reduced in dbcamp-treated ka31 cultures. capabilities for anchorage-independent growth we ...	1988	2835972
construction and characterization of a retroviral vector demonstrating efficient expression of cloned cdna sequences.	we describe the construction and properties of a retroviral expression vector, designated pmv-7, designed to transfer unselected cdnas and produce their encoded proteins in recipient cells. the vector is flanked by the long terminal repeats (ltrs) of the moloney murine sarcoma virus (msv) and contains the selectable drug resistance gene neo under the regulation of the herpes simplex virus (hsv) thymidine kinase (tk) promoter. unique eco ri and hind iii sites facilitate the introduction of sequen ...	1988	2836147
functional studies of newly synthesized benzoic acid derivatives: identification of highly potent retinoid-like activity.	three newly synthesized benzoic acid derivatives (terephthalic acid anilides, chalcone carboxylic acid, and azobenzene carboxylic acid), with a certain structural similarity to retinoic acid, were examined for their retinoid-like bioactivity and their capacity to bind to cellular retinoid binding proteins. two in vitro systems were used to evaluate their retinoid-like bioactivity: inhibition of adipose conversion of st 13 murine preadipose cells and growth promotion of murine sarcoma virus (msv) ...	1988	2836439
delayed hypersensitivity reactions to virus-augmented syngeneic and allogeneic tumor associated antigens.	delayed hypersensitivity (dh) reactions to intact msv-induced tumor cells or their crude membranes (cm) were studied across the h-2 histocompatibility barrier, using the radioisotopic footpad assay. allogeneic as well as syngeneic tumor cells or their cm produced significant dh reactions in msv-immune mice. cm from these cells after infection with influenza virus induced a stronger tumor-specific dh reaction in immune mice than did cm from uninfected cells. these results indicate that h-2 histoc ...	1988	2839400
anti-retrovirus activity of 3'-fluoro- and 3'-azido-substituted pyrimidine 2',3'-dideoxynucleoside analogues.	the 3'-fluoro-and 3'-azido-substituted derivatives of 2',3'-dideoxythymidine (ddthd), 2',3'-dideoxyuridine (ddurd), 2',3'-dideoxy-5-ethyluridine (ddeturd) and 2',3'-dideoxycytidine (ddcyd) have been synthesized and evaluated for their anti-retrovirus activity [against human immunodeficiency virus (hiv) and murine moloney sarcoma virus (msv)]. based on their 50% effective doses the most potent inhibitors of hiv replication in human mt4 lymphocytes were: fddthd (0.001 microm), azddthd (0.004 micro ...	1988	2840080
bifunctional activity of transforming growth factor type beta on the growth of nrk-49f cells, normal and transformed by kirsten murine sarcoma virus.	transformation of rat nrk-49f cells (49f) by kirsten murine sarcoma virus (ki-msv) renders these cells (ki-49f cells) capable of autonomous anchorage independent (ai) growth. as compared to nontransformed 49f cells, the transformation by ki-msv does not modify the cell response to transforming growth factor-beta (tgf-beta) in monolayer conditions, but alters it in a i growth conditions. the growth of nontransformed or ki-msv-transformed adherent 49f cells is slowed down by porcine tgf-beta, and ...	1988	2840442
increased formation of unintegrated viral dna in skin fibroblasts from patients with familial polyposis coli shortly after infection with kirsten murine sarcoma virus.	skin fibroblasts from patients with familial polyposis coli (fpc) exhibit increased frequency of morphological transformation, anchorage-independent growth, and enhanced production of viral rna and viral particles after infection with murine sarcoma virus(murine leukemia virus), msv(mlv). these fpc fibroblasts form greater amounts of unintegrated viral dna as compared to normal fibroblasts during the first 4 to 24 hr after infection with kirsten msv(kimlv), suggesting that increased susceptibili ...	1988	2846448
infectivity and complete nucleotide sequence of the genome of a south african isolate of maize streak virus.	the complete infectious genome of a south african isolate of the geminivirus maize streak (msv-s) has been cloned, characterized, and sequenced. using an a. tumefaciens ti plasmid delivery system, the cloned -2.7 kb single circular msv component was shown to be necessary and sufficient for infection of maize. based on sequence analysis of the infectious clone, msv-s is highly homologous to the previously characterized kenyan and nigerian isolates. while the genomic organization of msv-s has elem ...	1988	2829117
monoclonal antibody against ifn-gamma inhibits moloney murine sarcoma virus-specific cytotoxic t lymphocyte differentiation.	the role of autochthonous ifn- production was evaluated in immune reactions to moloney murine sarcoma virus (m-msv)-induced tumors which are characterized by spontaneous regression mainly caused by virus-specific ctl activity. a functional ifn- depletion, induced by repeated administration of mab anti-ifn- at the site of virus inoculation, prevented tumor regression in m-msv-injected mice. moreover, this antibody inhibited in vitro both proliferation and differentiation of m-msv-specific t lymph ...	1988	2830339
human bronchial epithelial cells neoplastically transformed by v-ki-ras: altered response to inducers of terminal squamous differentiation.	many human bronchial adenocarcinomas have been shown to contain an activated ki-ras oncogene (rodenhuis et al., n. engl. j. med. 317 929-935, 1987). to test the hypothesis that activated ki-ras may be causally related to human bronchial carcinogenesis, v-ki-ras oncogene was transferred into an established human bronchial epithelial cell line, beas-2b, by infection with kirsten murine sarcoma virus (ki-msv) or by transfection with a plasmid containing the transforming region of ki-msv. these cell ...	1988	3067190
antibodies against viral proteins can be produced effectively in response to the increased uptake of alpha 2-macroglobulin:viral protein conjugate by macrophages.	we have previously shown that foreign antigens conjugated to alpha 2-macroglobulin (alpha 2m) were effectively taken up by macrophages, which was followed by a remarkable increase in the proliferation of immune t cells. we present in this report that the production of antibodies against viral proteins can also be effectively achieved when viral proteins were conjugated to alpha 2m and fed to the in vitro immune system. proteins derived from kirstein murine sarcoma virus (ki-msv) were partially p ...	1988	2449204
nucleotide sequence of the geminivirus chloris striate mosaic virus.	the genome of chloris striate mosaic virus (csmv) comprises a single circular dna as determined by analyses on virion single-stranded (ss) dna and virus-specific covalently closed circular (ccc) dna isolated from infected plants. the nucleotide sequence of csmv dna was determined from cccdna and the data were accommodated into one dna circle of 2750 nucleotides. comparison of the nucleotide sequence with those of maize streak virus (msv), wheat dwarf virus (wdv), and digitaria streak virus (dsv) ...	1988	3369088
multistep carcinogenesis of normal human fibroblasts. human fibroblasts immortalized by repeated treatment with co-60 gamma rays were transformed into tumorigenic cells with ha-ras oncogenes.	two normal mortal human fibroblast cell strains were transformed into immortal cell lines, susm-1 and kmst-6, by treatment with 4-nitroquinoline 1-oxide (4nqo) and co-60 gamma rays, respectively. these immortalized cell lines showed morphological changes of cells and remarkable chromosome aberrations, but neither of them grew in soft agar or formed tumors in nude mice. the immortal cell line, kmst-6, was then converted into neoplastic cells by treatment with harvey murine sarcoma virus (ha-msv) ...	1988	3140712
effect of recombinant human interleukin 2 on the growth of a balb/c sarcoma induced by moloney murine sarcoma virus.	the effect of in vivo administration of recombinant interleukin 2 (ril2) on the growth of a primary female balb/c sarcoma induced by moloney murine sarcoma virus (m-msv) was studied. although low-dose administration of (6,000 ju/mouse x 14 days) ril2 had no effect on the growth of the tumors, high-dose (15,000-80,000 ju/mouse x 14 days) intraperitoneal inoculation of ril2 induced tumor regression, dose-dependently. tumors in mice which received 80,000 ju/mouse/day of ril2 regressed completely 2 ...	1988	3141331
changes in in vitro growth behaviour of the mammary epithelial cell line nmumg caused by the v-fos oncogene.	a defective retrovirus was constructed to investigate the effect of the expression of the v-fos oncogene from fbj-msv on the in vitro growth properties of the mammary epithelial cell line nmumg. clearly visible areas of overgrowth in monolayer cultures of nmumg were seen in cells infected with the v-fos-containing retrovirus but not in cells infected with control virus which did not contain an oncogene. two cell lines, representing two morphological types of infected cell, were isolated from a m ...	1988	3192336
detection of a non-structural protein of m r 11 000 encoded by the virion dna of maize streak virus.	a polypeptide of approximately 11 000 daltons (11 kda protein) encoded by an open reading frame (10.9 orf) from the virion sense of maize streak virus (msv) dna has been detected among the products of in vitro translation reactions programmed with rna from infected maize plants and also in total protein extracts from infected leaves. the 11 kda protein has not been detected in virions and is therefore proposed to have a nonstructural role.viral dna with an additional in-frame translation stop co ...	1988	24272158
the intergenic region of maize streak virus contains promoter elements involved in rightward transcription of the viral genome.	maize streak virus (msv), a geminivirus with a one-component genome, encodes a major coat protein rna which accumulates in infected plants. using a maize protoplast cell transient expression system, we have defined and studied the promoter which drives rightward transcription of the rna encoding the coat protein. we have identified a 122 bp upstream segment that enhances promoter activity and functions as an upstream activating sequence (uas). the uas lies in the starting intergenic region of th ...	1988	16453851
maize streak virus genes essential for systemic spread and symptom development.	the entire genome of single component geminiviruses such as maize streak virus (msv) consists of a single-stranded circular dna of ~2.7 kb. although this size is sufficient to encode only three average sized proteins, the virus is capable of causing severe disease of many monocots with symptoms of chlorosis and stunting. we have identified viral gene functions essential for systemic spread and symptom development during msv infection. deletions and gene replacement mutants were created by site-d ...	1989	16453874
marked in vivo antiretrovirus activity of 9-(2-phosphonylmethoxyethyl)adenine, a selective anti-human immunodeficiency virus agent.	9-(2-phosphonylmethoxyethyl)adenine (pmea) is a potent and selective inhibitor of the replication of human immunodeficiency virus (hiv) in vitro in human t-lymphocyte mt-4, h9, and ath8 cells. pmea also inhibits moloney murine sarcoma virus (mo-msv)-induced transformation of murine c3h embryo fibroblasts. moreover, pmea causes a dose-dependent suppression of tumor formation and associated mortality in mice inoculated with mo-msv. at a dose of 50 or 20 mg/kg per day pmea effected a 90-100% protec ...	1989	2911579
a cell mutant that exhibits temperature-dependent sensitivity to transformation by various oncogenes.	we previously isolated a fisher rat fibroblast mutant, b812, that has the unique property of temperature-dependent transformation by various oncogenic retroviruses. at the permissive temperature (35 degrees c), this mutant was sensitive to oncogenic transformation and formed foci on a dish at the same frequency as did the parental fibroblast cell line. when kirsten murine sarcoma virus (ki-msv) was applied to the cells, the frequency of focus formation decreased more than 25-fold at the nonpermi ...	1989	2479832
in vitro and in vivo growth control of transformed lymphoid cells expressing plasma membrane galactosyltransferase.	the level of beta 1-4 galactosyltransferase activity was examined in a number of spontaneously, chemically, or virally transformed murine tumor cell lines. increased levels of enzyme activity were observed for the murine myeloma cell line k181 and in vivo mopc 104e. the maloney sarcoma virus (msv) transformed t-cell lymphoma, yc-8, also demonstrated elevated levels of enzyme activity when compared to a second independently msv transformed t stem-cell lymphoma, lstra. cell surface immunofluoresce ...	1989	2510114
persistent suppression of virus-specific cytotoxic t cell responses after transient depletion of cd4+ t cells in vivo.	co-administration of soluble ag and anti-cd4 mab has been successfully used to induce long term ag-specific tolerance. the mechanisms underlying persistent immunologic unresponsiveness are unclear. we have now studied whether tolerance toward complex viral ag expressed on moloney sarcoma virus (msv)-transformed tumor cells can be induced when given at the time of severe helper cell depletion. although mice that had been injected with anti-cd4 mab at the time of immunization regained the ability ...	1989	2524530
a rat mutant cell clone showing temperature-dependent transformed phenotypes with functional expression of the src gene product.	the cellular mutant b814 isolated from a fischer rat cell line shows temperature-sensitivity of focus formation on infection with moloney murine sarcoma virus (mo-msv) and rous sarcoma virus (rsv). an rsv-transformed clone (s814-2) isolated from b814 cells shows temperature-sensitive transformed phenotypes for morphology, growth in soft agar, and glucose uptake. the expression, phosphorylation, and tyrosine kinase activity of pp60v-src in s814-2 were not affected at the nonpermissive temperature ...	1989	2535907
2'-5'-oligoadenylate synthetase gene expression in normal and murine sarcoma virus-transformed nih 3t3 cells.	mouse fibroblasts transformed by murine sarcoma virus (msv) are highly sensitive to the antiproliferative effect of interferon (ifn) (m. bakhanashvili, d. h. wreschner, and s. salzberg, cancer res. 43:1289-1294, 1983). to elucidate the mechanism leading to this ifn sensitivity, the expression of the 2'-5'-oligoadenylate synthetase (2-5a synthetase) gene, the presence of the 2-5a synthetase protein, and the level of its enzymatic activity were determined in ifn-treated and untreated cultures. nih ...	1989	2536824
secretion, glycosylation, and phosphorylation of rat-specific, transformation-associated proteins in moloney murine sarcoma virus-transformed rat cells.	previously, we detected, by monoclonal antibody, three moloney murine sarcoma virus (mo-msv)-activated intracellular transformation-associated proteins (tap), (p66, p63, and p60) in several mo-msv-transformed rat cell lines (chan et al., biochem. biophys. res. commun., 134: 1223-1230, 1986) and found the release of tap into the extracellular medium with a change from three intracellular polypeptides to two extracellular polypeptides (p68 and p64) (li et al., virology, 156: 91-100, 1987). since t ...	1989	2538234
regulation of ifn-gamma-induced host cell mhc antigen expression by kirsten msv and mlv. i. effects on class i antigen expression.	we have reported previously that the kirsten murine sarcoma virus (ki-msv) that carries the v-ki-ras oncogene prevents c3h10t 1/2 fibroblasts from being able to respond to interferon-gamma (ifn-gamma) with the expression of the class ii major histocompatibility complex (mhc) antigen, h-2a. in this report we investigate further as to whether msv or its parent virus kirsten murine leukaemia virus (ki-mlv) is able to reduce host class i mhc antigen expression. the results demonstrate that class i e ...	1989	2544513
regulation of ifn-gamma-induced host cell mhc antigen expression by kirsten msv and mlv. ii. effects on class ii antigen expression.	we have reported previously that the kirsten murine sarcoma virus (ki-msv), which carries the v-ki-ras oncogene, prevents the induction of the class ii mhc antigen h-2a and reduces the induction of class i mhc antigens by interferon-gamma (ifn-gamma) on c3h10t 1/2 fibroblasts. it is here shown that the abolition by the virus of h-2a expression extends also to class ii antigen h-2e and that this is maintained for at least 7 days after ifn treatment. in addition no concentration of ifn-gamma teste ...	1989	2544514
potentiating effect of ribavirin on the anti-retrovirus activity of 3'-azido-2,6-diaminopurine-2',3'-dideoxyriboside in vitro and in vivo.	3'-azido-2,6-diaminopurine-2',3'-dideoxyriboside (azdddapr) is a potent and selective inhibitor of human immunodeficiency virus (hiv) replication in vitro. it also inhibits moloney murine sarcoma virus (msv)-induced transformation of murine c3h/3t3 embryo fibroblasts. azdddapr causes a marked dose-dependent suppression of msv-induced tumor formation and mortality therewith associated in newborn mice infected with msv. combination of azdddapr with ribavirin resulted in a marked potentiation of it ...	1989	2545163
c-fos expression induces bone tumors in transgenic mice.	the proto-oncogene c-fos has been isolated as the cellular homolog of the v-fos gene found in the osteosarcoma inducing fbr- and fbj-murine sarcoma viruses (msv). expression of the c-fos gene in transgenic mice leads to the development of bone lesions of which about half progress to bone tumors mainly chondrosarcomas. the tumors display a strong preference for males and have a latency with a mean of 9.5 months. however, also mice without visible lesions develop bone tumors with the same sex pref ...	1989	2547184
mutational analysis of the virion-sense genes of maize streak virus.	insertion and deletion mutagenesis of the two virion-sense genes, v1 and v2, of maize streak virus (msv) prevents symptomatic infections following agrobacterium-mediated 'agroinoculation' of maize seedlings. these genes code for an mr 10900 protein and for coat protein, respectively. mutants containing insertions or deletions in the coat protein gene, v2, were able to replicate to low levels, producing dsdna although virion ssdna was not detected and symptoms were not observed. hence, unlike the ...	1989	2550570
biochemical characterization of a virus-induced osteosarcoma-like osseous lesion in vitro.	chondroprogenitor cells present in the apical and lateral parts of the mandibular condyle from neonatal mice differentiate towards the osteoblastic lineage and form bone within 7 days in culture. infection of condylar explants with the fbr osteosarcoma virus (fbr msv) results in the transformation of cells in the progenitor zone, previously identified as the target for the virus, and the formation of a transplantable osteosarcoma-like lesion. morphological and biochemical changes in this system ...	1989	2553223
acutely transforming retroviruses as carcinogens in mouse embryos.	spontaneous and induced transmission of oncogenic retroviruses from parents to offspring is well documented in mammals, as exemplified by murine leukaemia viruses. in addition, it is now common knowledge that transgenic mice, carrying viral and cellular transforming genes, can show unusual tumour incidences and can transmit this character to successive generations. the present report deals with the occurrence of tumours in rodents exposed directly in utero to murine sarcoma viruses (msv). attent ...	1989	2553597
glucocorticoid-enhanced neoplastic transformation of human keratinocytes by human papillomavirus type 16 and an activated ras oncogene.	human papillomaviruses (hpv) are known etiological agents of benign proliferation of the skin and mucosa (papillomas and warts). they have also been implicated in the development of cervical dysplasia and anogenital carcinoma. the close association of hpv type 16 dna with the majority of cervical carcinomas suggests the involvement of the virus in this type of cancer. we have developed an in vitro multistep model for human epithelial cell carcinogenesis. primary human epidermal keratinocytes acq ...	1989	2556855
9-(2-phosphonylmethoxyethyl)-2,6-diaminopurine (pmedap): a novel agent with anti-human immunodeficiency virus activity in vitro and potent anti-moloney murine sarcoma virus activity in vivo.	9-(2-phosphonylmethoxyethyl)-2,6-diaminopurine (pmedap) is a potent inhibitor of the replication of human immunodeficiency virus (hiv) in human t-lymphocyte mt-4 cells (50% effective dose: 2 microm). pmedap strongly inhibited moloney murine sarcoma virus (msv)-induced transformation of murine c3h/3t3 embryo fibroblasts and caused a dose-dependent suppression of tumor formation and mortality in newborn mice inoculated with msv. even at a dose as low as 0.25 mg/kg/day, pmedap effected a significan ...	1989	2559845
characterization of southern african isolates of maize streak virus: typing of three isolates by restriction mapping.	the genomic replicative form dnas (rf-dna) of three maize streak virus isolates (msv-ct, msv-pe, and msv-sw) from widely separated locations in southern africa were characterized by restriction endonuclease mapping in order to assess the feasibility of using the technique to determine genetic variability between isolates. the viruses were transmitted to and propagated in laboratory-grown maize by the leafhopper vector cicadulina mbila (naudé). msv-pe produced more severe symptoms than msv-ct and ...	1989	2566588
computer analysis between nucleotide and amino acid sequences of bean golden mosaic virus and those of maize streak, wheat dwarf, chloris striate mosaic, and beet curly top viruses.	bean golden mosaic virus (bgmv) dna 1 and 2 have little sequence homology with maize streak virus (msv), wheat dwarf virus (wdv), and chloris striate mosaic virus (csmv) dnas. bgmv dna 1 and beet curly top virus (bctv) dna are closely related, whereas bgmv dna 2 and bctv dna are not related. direct amino acid homologies of predicted proteins between bgmv orfs and msv orfs, wdv orfs or csmv orfs were 40-50%. bgmv 1l1 and bctv l1, and bgmv il3 and bctv l4 were highly conserved. the sequence taatat ...	1989	2615677
neoplastic transformation of human epithelial cells in vitro.	efforts to investigate the progression of events that lead human cells of epithelial origin to become neoplastic in response to carcinogenic agents have been aided by the development of tissue culture systems for propagation of epithelial cells. we have recently developed an in vitro multistep model suitable for the study of human epithelial cell carcinogenesis. primary human epidermal keratinocytes acquired indefinite lifespan in culture but did not undergo malignant conversion in response to i ...	1989	2686534
evolutionary relationship of three southern african maize streak virus isolates.	the aligned restriction endonuclease maps of three sequenced maize streak virus isolates, three restriction-mapped southern african maize streak virus isolates, and two other sequenced geminiviruses were used as a means of calculating the sequence divergence between these viruses. the degree of divergence was used to construct a phylogenetic tree for the viruses; this tree agrees well with predictions from sequence comparisons, and so the method can be used to study the relationship of geminivir ...	1989	2722470
dna transfer from agrobacterium to zea mays or brassica by agroinfection is dependent on bacterial virulence functions.	dna transfer from agrobacterium tumefaciens, a soil bacterium, to the non-host graminaceous monocotyle-donous plant zea mays, was analysed using the recently developed technique of agroinfection. agroinfection of z. mays with maize streak virus using strains of a. tumefaciens carrying mutations in the ptic58 virulence region showed an almost absolute dependence on the products of the bacterial virc genes. in contrast, agroinfection of the control host brassica rapa with cauliflower mosaic virus ...	1989	2770696
specificity of agrobacterium-mediated delivery of maize streak virus dna to members of the gramineae.	parameters affecting the efficiency of agroinfection of maize streak virus (msv) in maize have been determined. monomeric units, cloned at a number of sites in the msv genome were not infectious but multimeric units containing partial duplications were equally as infectious as complete tandem dimeric clones. inoculation of tandem dimeric units conjugated into different strains of agrobacterium showed that both a. tumefaciens and a. rhizogenes were able to transfer dna to maize and this ability w ...	1989	24272715
the intergenic region of maize streak virus contains a gc-rich element that activates rightward transcription and binds maize nuclear factors.	maize streak virus (msv) is transcribed bidirectionally from an intergenic region and rightward transcription produces an rna that encodes the coat protein. the intergenic region contains promoter elements required for rightward transcription including an upstream activating sequence (uas) which endows the promoter with full activity in a maize transient expression system. the uas contains two gc-rich repeats (gc boxes) and a long inverted repeat or hairpin with a loop harboring a taatattac sequ ...	1990	2103478
potentiating effect of ribavirin on the in vitro and in vivo antiretrovirus activities of 2',3'-dideoxyinosine and 2',3'-dideoxy-2,6-diaminopurine riboside.	2',3'-dideoxyinosine (ddi) and 2',3'-dideoxy-2,6-diaminopurine riboside (dddapr) are potent and selective inhibitors of human immunodeficiency virus (hiv) replication in mt-4 cells. they are also inhibitory to the transformation of c3h/3t3 cells by moloney murine sarcoma virus (msv). in vivo, they are only marginally effective in delaying msv-induced tumor formation, and mortality associated therewith in newborn nmri mice. when combined with ribavirin, ddi and dddapr become much more effective i ...	1990	2123003
s-antigen and rod-opsin immunoreactions in midline brain neoplasms of transgenic mice: similarities to pineal cell tumors and certain medulloblastomas in man.	transgenic mice expressing the large t-antigen of the simian virus 40 (sv 40) under the control of 1) the enhancer of moloney murine sarcoma virus (msv) and 2) the sv 40 promoter develop undifferentiated neuroectodermal tumors located in the midline of the dorsal brain surface, abnormalities in lens fiber differentiation and retinal dysplasia. in this study the brain neoplasms of six adult animals and the brain of one 11-day old mouse were examined by conventional histology and immunocytochemica ...	1990	2141872
moloney murine sarcoma virus 349 induces kaposi's sarcomalike lesions in balb/c mice.	moloney murine sarcoma virus (momusv349) is produced by musv349 cells in at least eight-fold excess over the replication-competent helper virus. less than 48-hours-old balb/c mice inoculated intraperitoneally with supernatant from musv349 cells containing approximately 10(4) musv349 infectious units developed clinical symptoms, including severe generalized wasting, 15 to 20 days after inoculation. these infected mice became moribund 35 to 45 days after inoculation. gross examination of the bodie ...	1990	2158239
sequence-specific dna binding of the proto-oncoprotein ets-1 defines a transcriptional activator sequence within the long terminal repeat of the moloney murine sarcoma virus.	the ets proto-oncogene family is a group of sequence-related genes whose normal cellular function is unknown. in a study of cellular proteins involved in the transcriptional regulation of murine retroviruses in t lymphocytes, we have discovered that a member of the ets gene family encodes a sequence-specific dna-binding protein. a mouse ets-1 cdna clone was obtained by screening a mouse thymus cdna expression library with a double-stranded oligonucleotide probe representing 20 bp of the moloney ...	1990	2163347
characterization of fos-induced osteogenic tumours and tumour-derived murine cell lines.	osteogenic tumours from c-fos (mt-c-fos-ltr)-transgenic mice and from mice infected with the v-fos-bearing fbr murine osteosarcoma virus (fbr msv) showed close morphological and neoplastic similarities. fos mrna expression was elevated in both types of tumours, and expression of several genes characteristic of differentiated bone cells was either lower, enhanced, or not detectable in comparison to that in normal bone. tumour-derived cell lines showed variable levels of exogenous fos expression; ...	1990	2178137
detection and typing of maize streak virus and other distantly related geminiviruses of grasses by polymerase chain reaction amplification of a conserved viral sequence.	the application of the polymerase chain reaction dna amplification technique to the detection and typing of isolates of maize streak virus (msv) and other related geminiviruses of grasses is described. the oligonucleotide primers used for amplification were 17-mers which contained a number of degeneracies. an approximately 250 base pair fragment was amplified from all geminivirus-infected grass and cereal samples tested. the amplification reaction was specific, working down to a concentration of ...	1990	2254750
inhibitory effects of 9-(2-phosphonylmethoxyethyl)adenine and 3'-azido-2',3'-dideoxythymidine on tumor development in mice inoculated intracerebrally with moloney murine sarcoma virus.	9-(2-phosphonylmethoxyethyl)adenine (pmea), a potent inhibitor of human immunodeficiency virus (hiv), caused a dose-dependent suppression of tumor formation, and mortality associated therewith, in 6-day-old nmri mice inoculated intracerebrally with moloney murine sarcoma virus (msv). even at a dose as low as 1 mg/kg/day, pmea effected a significant delay in tumor formation. when evaluated in parallel with pmea, 3'-azido-2',3'-dideoxythymidine (azt) conferred a comparable tumor-inhibitory effect ...	1990	2307539
development of an in vitro model of tumor progression using v-raf and v-raf/v-myc transformed rat liver epithelial cells: correlation of tumorigenicity with the downregulation of specific proteins.	a series of clonal cell lines were derived from rat liver epithelial cells after being infected with a defective retrovirus containing either v-raf (3611-msv) or v-raf/v-myc(j2) together with a helper virus. these clones exhibited a different morphology from the regular cuboid shape of the control cells, infected only with the helper virus. all of the infected cell lines contained at least one full length copy of appropriate proviral dna and expressed comparable levels of v-raf mrna, although on ...	1990	2322386
lactate dehydrogenase-elevating virus induces antibodies reactive with a surface antigen of aetiologically unrelated murine cell transformants.	mice infected with lactate dehydrogenase-elevating virus (ldv) developed antibodies reactive with a tumour cell surface antigen (tsa) of moloney sarcoma virus (mo-msv)-transformed mouse cells (sac). we demonstrate that stu mice infected with ldv were protected against growth of syngeneic sac tumour cells as early as 23 days post-infection (p.i.) and up to 5 months p.i. nine ldv strains, including the neurovirulent ldv-c, elicited production of anti-tsa antibodies, which were restricted to the ig ...	1990	2345370
anti-retrovirus activity of 9-(2-phosphonylmethoxyethyl)adenine (pmea) in vivo increases when it is less frequently administered.	different treatment schedules have been investigated when evaluating the inhibitory effect of 9-(2-phosphonylmethoxyethyl)adenine (pmea) and 3'-azido-2',3'-dideoxythymidine (azt) on the replication of human immunodeficiency virus type i (hiv-i) in mt-4 cells, transformation of c3h/3t3 cells by moloney murine sarcoma virus (msv), and msv-induced tumor formation in newborn nmri mice. shortening the exposure time of hiv-i-infected mt-4 cells to pmea or azt led to an increase in the selectivity inde ...	1990	2384280
serotyping and strain identification of maize streak virus isolates.	four strains of maize streak virus, namely the panicum maximum, digitaria setigera and sugarcane strains, have been identified from 19 isolates by elisa using polyclonal antisera cross-absorbed with particles of the maize strain. the results suggest there is an epitope of the maize strain which is not dependent on the capsid being intact and which is common to all the members of the group; other strain-specific epitopes are probably conformation-dependent. a specific epitope (probably internal) ...	1990	1697327
involvement of interferon-system in the regulation of cell growth and differentiation.	in this report we review the current knowledge on the involvement of the interferon (ifn) system in the regulation of cell growth and differentiation. we also summarize our own data which provide evidence for the strong correlation between ifn-mediated growth-arrest of transformed cells and the elevated enzymatic activity of an ifn-induced protein. similarly, it is demonstrated that elevated levels of ifn-induced proteins accompany the early phases of in-vitro cell differentiation. ifn-treatment ...	1990	1698310
the influence of morphine on development of hsv-1 and m-msv virus infection in mice.		1990	1715654
single-dose administration of 9-(2-phosphonylmethoxyethyl)adenine (pmea) and 9-(2-phosphonylmethoxyethyl)-2,6-diaminopurine (pmedap) in the prophylaxis of retrovirus infection in vivo.	9-(2-phosphonylmethoxyethyl)adenine (pmea) and 9-(2-phosphonylmethoxyethyl)-2,6-diaminopurine (pmedap) are selectively inhibitory to human immunodeficiency virus and other retroviruses. we have now investigated the effects of different pmea and pmedap treatment schedules in newborn mice infected with moloney murine sarcoma virus (msv). administration of a single dose of pmea or pmedap on the day of msv inoculation conferred a greater protective effect against msv-induced tumor formation than whe ...	1991	1776876
ras oncogene activates the intracisternal a particle long terminal repeat promoter through a c-amp response element.	to understand the mechanism responsible for the high expression of intracisternal a particles (iap) in murine cells transformed by the kirsten mouse sarcoma virus (ki-msv), we have investigated the effect of p21ras on iap transcription. by transient cotransfections of iap ltr-cat plasmids with v-ki-ras and c-ki-ras expression vectors, we have found that p21v-ki-ras, and the p21c-ki-ras to a lesser extent, stimulate the promoter activity of the 5' iap ltr. we constructed several plasmids containi ...	1991	1828874
moloney murine leukemia virus tolerance in anti-cd4 monoclonal antibody-treated adult mice.	adult mice injected with moloney murine leukemia virus (m-mulv) 1 day after a short term treatment with anti-cd4 mab developed t cell lymphomas, or sarcomas when rechallenged with moloney murine sarcoma virus (m-msv). neoplastic development was correlated with virus spread, as thymic and peripheral t and b lymphocytes promptly expressed m-mulv-induced ag after virus introduction; no virus-specific ctl generation was detected in mltc. this failure, which was selective for m-mulv-induced ag, persi ...	1991	1833453
derivatives of moloney murine sarcoma virus capable of being transcribed in embryonal carcinoma stem cells have gained a functional sp1 binding site.	the long terminal repeat (ltr) sequences of moloney murine leukemia virus and its closely related derivative moloney murine sarcoma virus (mo-msv) are incapable of directing transcription in embryonal carcinoma (ec) stem cells. the myeloproliferative sarcoma virus, a derivative of mo-msv, has several point mutations in the ltr and is transcribed more efficiently to allow productive infection of f9 ec cells. one of these mutations, at -166 with respect to the transcriptional start, creates a cons ...	1991	1848307
mutational analysis of the small intergenic region of maize streak virus.	maize streak virus (msv) is a leafhopper-transmitted geminivirus containing one molecule of circular single-stranded dna of about 2.7 kb. we have tested the infectivity of msv mutants. a deletion of 29 bases in the small intergenic region (sir) did not affect the infectivity of msv. mutants containing insertions of oligonucleotides of up to 32 bases at the asni site in sir were also infectious. however, the infection efficiency of the insertion mutants decreased as the size of the oligonucleotid ...	1991	1853570
transduction of the cho aprt gene into mouse l cells using an adeno-5/aprt recombinant virus.	an adenovirus-5 recombinant virus adapt1 carrying the chinese hamster ovary (cho) adenine phosphoribosyltransferase (aprt) gene was constructed by insertion of a 2.5-kb fragment containing the complete cho aprt structural gene linked to a moloney murine sarcoma virus (msv) promoter into the e3 region of adenovirus-5. the cho aprt gene was in the opposite orientation to the adenovirus e3 promoter. mouse lapt- tk- (lat) cells expressed the cho aprt gene when infected with the virus, even at low mo ...	1991	1887332