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molecular analysis of a pro-t cell clone transformed by abelson-murine leukemia virus, displaying progressive gamma delta t cell receptor gene rearrangement and surface expression.we present a molecular analysis of t cell differentiation in a set of clones derived from in vitro abelson murine leukemia virus (a-mulv) infection of fetal liver cells. the parental clone had partial rearrangement of the beta and gamma loci and spontaneously displayed progressive rearrangement of v gamma genes during in vitro culture. further differentiation of these clones leading to delta gene rearrangement and cd4 expression, then cd8, cd3 and t cell receptor gamma delta chain surface expres ...19921322302
b cell deficiency progresses with lineage maturation in nude.x-linked immunodeficient mice b cell deficiency progresses with lineage maturation.previously we showed that unlike normal, nude, or x-linked immune deficient (xid) mice, nude.xid mice are deficient in bone marrow pre-b cell targets for abelson murine leukemia virus transformation. we show that nude.xid bone marrow is deficient in both cd45(b220)+ and cd45(b220)- surface (s)igm- progenitors that give rise to b cell colonies in whitlock-witte cultures. cd45(b220)+ precursors had normal differentiation potential in vitro. cd45(b220)- precursors differentiated into cd45(b220)+ ce ...19921385525
transitory expression of thy-1 antigen in immature b cell lines.in cmu- b220+ thy-1- murine immature b cells transformed with a temperature-sensitive mutant of abelson murine leukemia virus, a low level of thy-1 antigen was transitorily expressed after the shift of the culture temperature from the permissive (35 degrees c) to the non-permissive (39 degrees c) temperature. on the other hand, b220 antigen was persistently expressed regardless of whether the cells were cultured at the permissive or non-permissive temperature. no other t-lineage-specific antigen ...19921347756
abelson antigen is expressed on hematopoietic spleen colony-forming cells from mice carrying the av-2s virus sensitivity gene.abelson antigen is a cell-surface determinant specifically induced by the abelson murine leukemia virus (a-mulv); this antigen is also expressed on uninfected bone marrow of balb/c mice. antisera that contained antibody to abelson antigen were cytotoxic for the spleen colony-forming cells (cfu-s) of adult bone marrow from balb/c mice. absorption tests with appropriate tissues and direct cytotoxic tests with bone marrow cfu-s from several mouse strains confirmed that the sensitivity of balb/c cfu ...1979228287
the nonstructural component of the abelson murine leukemia virus polyprotein p120 is encoded by newly acquired genetic sequences.the abelson leukemia virus (ablv) polyprotein p120 is compared to translational products representing the entire moloney murine leukemia virus (mulv) genome on the basis of [35s]methionine tryptic peptide composition. three methionine-containing tryptic peptides present in moloney pr65gag are each shown to be present in both pr75gag and in pr180gag-pol. of these, one peptide, corresponding to moloney mulv p12, but neither of two p30-specific peptides are present in ablv p120. among the 12 remain ...1979229259
infection of mouse bone marrow cells with abelson murine leukemia virus and establishment of producer cell lines. 1979232471
selective inhibition of proliferation in v-abl- and bcr-abl-transformed cells by a nucleoside analog.the nucleoside analog acyclovir (9-[2-hydroxy-ethoxy)methyl]guanine or acycloguanosine; acv) inhibited the in vitro transformation of nih 3t3 cells by abelson murine leukemia virus and the proliferation of abl- and bcr-abl-transformed hemopoietic murine cell lines. this effect is selective since acv at the same concentration had no effect on the src and ha-ras transformation of nih 3t3 cells or on the proliferation of hemopoietic cells transformed by those oncogenes. the inhibitory effect on pro ...19921331046
transformation of immature lymphoid cells by abelson murine leukemia virus. 1979397920
immunoglobulin synthesis by lymphoid cells transformed in vitro by abelson murine leukemia virus.the majority of cell lines derived by infection of murine bone marrow cells with abelson murine leukemia virus (a-mulv) synthesize a mu chain but no detectable light chain. aside from this mu-only phenotype, lines that make only light chain, both chains or no immunoglobulin-related polypeptides have also been found. two lines have been studied in detail: one that makes only mu chain and one that makes only kappa light chain. synthesis of both polypeptides can be increased by modifying the cultur ...1979222460
abelson antigen: a viral tumor antigen that is also a differentiation antigen of balb/c mice.we report here the serologic detection of a cell surface antigen common to cells transformed by the abelson murine leukemia virus (a-mulv) and to normal hematopoietic cells from certain strains of mice. serum from c57bl/6 mice hyperimmunized with syngeneic a-mulv lymphoma cells was cytotoxic for the immunizing cells; this reaction was used as the serologic test system for recognition of a-mulv antigens. absorption analysis using 40 tumors and 21 cell lines revealed that two serologic specificiti ...1978211509
cells nonproductively transformed by abelson murine leukemia virus express a high molecular weight polyprotein containing structural and nonstructural components.cell clones nonproductively transformed by the replication-defective abelson strain of murine leukemia virus (ablv) were analyzed for type c viral antigen expression by competition immunoassay. ablv-transformed mink non-producer lines were found to express a 110,000- to 130,000-molecular weight polyprotein containing murine leukemia virus gag proteins p15 and p12 covalently linked to nonstructural ablv-coded component(s) of around 80,000-100,000 molecular weight. this polyprotein lacked detectab ...1978211510
in vitro induction of continuous acute promyelocytic leukemia cell lines by friend or abelson murine leukemia virus. 1979219924
immunoglobulin production by lymphosarcomas induced by abelson virus in mice.a brief review of the origin and tumor-inducing properties of abelson murine leukemia virus is given. the most common neoplasm induced by this virus in vivo is a nonthymic lymphocytic tumor of bone marrow and lymph node origin. two morphologic types of lymphosarcomas are the undifferentiated lymphosarcoma (ls) and the plasmacytic lymphosarcoma (pl). with the electron microscope, both tumor cell types may be mixed and contain undifferentiated cells or cells with a moderate amount of rough endopla ...1978219359
abelson murine leukemia virus-infected cell lines defective in transformation. 1979224582
identification of an abelson murine leukemia virus-encoded protein present in transformed fibroblast and lymphoid cells.extracts from lymphoid and fibroblast cell lines transformed by abelson murine leukemia virus (a-mulv) contain a protein of molecular weight 120,000 (p120). immunoprecipitation with specific sera shows that p120 contains regions homologous to the 5'-terminal segment of the mulv gag gene complex--p15, p12, and at least part of p30--but lacks detectable determinants of p10, reverse transcriptase, and the envelope glycoprotein. p120 is phosphorylated and has an intracellular half-life of 3--6 hr. i ...1978209468
effect of pseudotype on abelson virus and kirsten sarcoma virus-induced leukemia.nonproducer cells transformed by kirsten sarcoma virus (kisv) or abelson murine leukemia virus (a-mulv) were infected with n- or nb-tropic helper viruses to rescue the defective transforming virus. the titer of the transforming viruses was determined on nih/3t3 fibroblast-like cells and cell-free filtrates of virus stock were inoculated into newborn fv-1nn mice. friend, moloney, and rauscher group of mulv (fmr) pseudotypes of kisv induced an erythroid leukemia efficiently, while an endogenous he ...1978206644
the effect of helper virus on abelson virus-induced transformation of lymphoid cells.abelson murine leukemia virus (a-mulv)-transformed fibroblast nonproducer cells were used to prepare a-mulv stocks containing a number of different helper viruses. the oncogenicity of the a-mulv stocks was tested by animal inoculation and their ability to transform normal mouse bone marrow cells was measured in vitro. all of the a-mulv stocks transformed fibroblast cells efficiently. however, only a-mulv stocks prepared with helper viruses that are highly oncogenic were efficient in vivo and in ...1978206646
in vitro transformation of lymphoid cells by abelson murine leukemia virus.cell cultures prepared from fetal murine liver were infected by abelson murine leukemia virus. after about 2 weeks, proliferating cells of lymphoid morphology appeared in some of the cultures. addition of 2-mercaptoethanol to the initial culture medium greatly enhanced the appearance of the lymphoid cells. immunoglobulin determinants were evident on the cells in some cultures. continuous passage of the cells in certain cultures was possible and the passaged cells could form tumors after animal i ...1975168584
a quantitative assay for transformation of bone marrow cells by abelson murine leukemia virus.a quantitative abelson murine leukemia virus (a-mulv) lymphoid cell transformation assay has been developed using a semisolid agarose culture system. under these conditions lymphoid cell transformation was shown to vary linearly with the dose of a-mulv used. the susceptibility of bone marrow cells from different strains of mice to a-mulv-induced transformation can be estimated using the agarose assay. strains with bone marrow cells of high, medium, and low susceptibility to a-mulv can be identif ...1976178822
induction of immunoglobulin synthesis in abelson murine leukemia virus-transformed mouse lymphoma cells in culture. 1977196804
cell populations and known surface antigens of tumors induced by abelson virus in pristane-primed balb/c mice: an analysis by immunoelectron microscopy;.when abelson murine leukemia virus (mulv-a) was inoculated into pristane-primed balb/c mice, either plasmacytomas (pct), lymphosarcomas, or their mixed form was induced with a shorter latent period than that for pct induction in mice treated with pristane alone. all 3 neoplasms were designated abelson's tumors. the morphology of the induced malignant cells and the presence of known surface antigens were analyzed by electron microscopy. the cell surface antigens (csa) examined were pc1, x.1, gros ...1975173861
virus production by abelson murine leukemia virus-transformed lymphoid cells.cell lines obtained by in vitro transformation of bone marrow with abelson murine leukemia virus (a-mulv) can be divided into three classes: producers, releasing reverse transcriptase-containing particles and infectious virus; nonproducers, releasing no viral particles; and defective producers, the most common phenotype, releasing particulate reverse transcriptase in the absence of infectious virus. when such cell lines were analyzed 1 to 2 weeks after their isolation, however, all produced infe ...197990175
functional homology between n-myc and c-myc in murine plasmacytomagenesis: plasmacytoma development in n-myc transgenic mice.mouse plasmacytomas induced by pristane oil alone, or in combination with abelson murine leukemia virus (a-mulv), regularly carry one of three alternative chromosomal translocations that juxtapose c-myc to immunoglobulin heavy- or light-chain loci. e mu-c-myc transgenic mice develop translocation-free plasmacytomas after induction by pristane oil and/or a-mulv [sugiyama, h., silva, s., wang, y., weber, g., babonits, m., rosen, a., wiener, f. & klein, g. (1990). int. j. cancer, 46, 845-852]. in o ...19921375720
preparation of syngeneic tumor regressor serum reactive with the unique determinants of the abelson murine leukemia virus-encoded p120 protein at the cell surface.antisera reactive with the abelson murine leukemia virus (a-mulv)-specified p120 (anti-abt sera) were produced in c57l/j mice. of many strains tested, only c57l/j reproducibly rejected syngenic a-mulv-induced tumor cells; after multiple immunizations their sera would immunoprecipitate both p120 and moloney-mulv (m-mulv) proteins. using labeled a-mulv-induced nonproducer cells, only p120 could be detected by anti-abt sera, suggesting that it may be the only a-mulv-specified protein. reactivity of ...197992572
lymphoid cells transformed by abelson virus require the v-abl protein-tyrosine kinase only during early g1.cells infected with temperature-sensitive transformation mutants of the abelson murine leukemia virus express low levels of kinase activity at the nonpermissive temperature, causing transformed pre-b cells to die under these conditions. examination of cell cycle profiles of such populations prior to cell death reveals that the cells accumulate in the g1 phase of the cell cycle. following g1 arrest, the cells die via apoptosis, an active process of cell elimination. cell synchronization and tempe ...19921379715
the ig vh repertoire of fetal liver-derived pre-b cells is influenced by the expression of a gene linked to x-linked immune deficiency.ig vh repertoire differences between normal and x-linked immune deficiency- (xid) expressing mice are well established. to test the hypothesis that such differences might exist as early as the pre-b stage of ontogeny we generated panels of xid fetal liver derived abelson murine leukemia virus transformants with h chain ig vdj rearrangements. cells from cba/tufts.xid mice used vh genes from many families, with no demonstrable preference for 3' genes. analysis of cells derived from (cba/tufts.xid ...19921541830
a retrovirus that expresses v-abl and c-myc oncogenes rapidly induces plasmacytomas.abl-myc, a murine retrovirus that encodes the v-abl and c-myc oncogenes, was constructed from abelson murine leukemia virus (a-mulv) in order to assess the biological consequences of co-expression of these genes in lymphoid cells. when inoculated into mice this retrovirus induced plasmacytomas in up to 100% of infected mice and less frequently induced pre-b lymphomas. both tumor types contained genome-length proviruses in one or a few chromosomal locations, were mono- or oligoclonal as judged by ...19921565479
oncogenic v-abl tyrosine kinase can inhibit or stimulate growth, depending on the cell context.the v-abl oncogene of abelson murine leukemia virus (a-mulv) induces two opposite phenotypes in nih3t3 cells. in the majority of cells, v-abl causes a growth arrest at the g1 phase of the cell cycle; while in a minority of cells, v-abl abrogates the requirement for growth factors. using temperature sensitive mutants, it can be demonstrated that v-abl tyrosine kinase is required for growth inhibition or stimulation. the two phenotypes are not caused by mutations or differences in the expression o ...19921396587
bone marrow-transforming activity of linker insertion mutants of abelson murine leukemia virus.two sets of mutants of the abelson murine leukemia virus, generated by linker insertion mutagenesis of a cloned proviral dna, were tested for their ability to transform bone marrow cultures in vitro. all the viruses retained an intact tyrosine kinase domain and were competent for transformation of nih3t3 fibroblasts in culture. one series contained 12-bp linker insertions in the regions flanking the kinase domain, and the other contained frameshift mutations that truncated the gene product downs ...19921437154
heavy chain variable (vh) region diversity generated by vh gene replacement in the progeny of a single precursor cell transformed with a temperature-sensitive mutant of abelson murine leukemia virus.sequence analysis of a large number of dna clones containing a functional heavy chain variable, diversity, and joining (vhdjh) complex generated by vh to vhdjh joining (vh gene replacement) in the progeny derived from a common precursor cell transformed with a temperature-sensitive (ts) abelson murine leukemia virus (a-mulv) indicates that endogenous vh gene replacement in vitro generates immunoglobulin gene joints distinct from those generated by the usual vh to djh joining. such joints keep th ...19921402663
structure of the abelson murine leukemia virus genome.virions produced from cells transformed by a-mulv contain a 30s, 5.6 kb rna that can be translated in a cell-free system to form the characteristic a-mulv protein. this rna was mapped by heteroduplex methods using dna probes from m-mulv, the presumed parent of a-mulv. the overall organization of the rna was determined by using full-length m-mulv reverse transcribed dna and visualizing the heteroduplexes in the electron microscope. this showed that a-mulv and m-mulv have homologous sequences at b ...1979229975
regulation of thy-1 gene expression by the methylation of the 5' region of thy-1 gene and intracellular regulatory factors in immature b cells.in c mu- b220+ thy-1- fl2-52-2, an immature b cell line transformed with a temperature-sensitive mutant of abelson murine leukemia virus(ts os-59), thy-1 antigen expression was induced after the shift of the culture temperature from a permissive(35 degrees c) to a non-permissive temperature(39 degrees c), and a thy-1+ subclone, fl2-52-2-1 was isolated by limiting dilution. furthermore, since a population of thy-1+fl2-52-2-1 lost thy-1 antigen expression during culture at a non-permissive tempera ...19921587555
benzopyranones and benzothiopyranones: a class of tyrosine protein kinase inhibitors with selectivity for the v-abl kinase.abelson murine leukemia virus is an acutely transforming replication-defective virus which encodes a transforming protein with tyrosine-specific protein kinase activity. a variety of benzopyranone and benzothiopyranone derivatives have been identified which selectively inhibit the v-abl tyrosine protein kinase with 50% inhibitory concentrations ranging from 1 to 30 microm. the most active derivative inhibited v-abl with a ki value of 0.9 microm. active derivatives showed selectivity for the v-ab ...19921643641
rag-2-deficient mice lack mature lymphocytes owing to inability to initiate v(d)j rearrangement.we have generated mice that carry a germline mutation in which a large portion of the rag-2 coding region is deleted. homozygous mutants are viable but fail to produce mature b or t lymphocytes. very immature lymphoid cells were present in primary lymphoid organs of mutant animals as defined by surface marker analyses and abelson murine leukemia virus (a-mulv) transformation assays. however, these cells did not rearrange their immunoglobulin or t cell receptor loci. lack of v(d)j recombination a ...19921547487
human b-lymphocyte precursors do not express the n-myc gene.n-myc expression has been reported in neuroblastoma, retinoblastoma and small cell lung carcinoma. increased expression associated with gene amplification in neuroblastoma correlates with disease stage and prognosis. n-myc expression has been observed in diverse murine tissues during early stages of development with loss of expression in later stages. abelson murine leukemia virus (a-mulv)-transformed pre-b cells express n-myc, whereas mature b cells do not. to determine whether human b-lymphocy ...19921571096
purification and characterization of dna polymerases from the plasmacytoma mopc 104e and abelson murine leukemia viruses.rna-dependent dna polymerases of intracisternal a particles from the mouse plasma cell tumor mopc 104e and of abelson murine leukemia virus (a-mulv) were isolated from particle preparations by nonidet p40 and ultrasonic treatment and purified by column chromatography on deae-cellulose and phosphocellulose, followed by centrifugation in linear sucrose gradients. both dna polymerases were very similar in their elution patterns from phospho and deae-cellulose, template specificities, requirements f ...1978206440
a 41-kilodalton protein is a potential substrate for the p210bcr-abl protein-tyrosine kinase in chronic myelogenous leukemia cells.chronic myelogenous leukemia (cml) is characterized by a translocation involving the c-abl protein-tyrosine kinase gene. a chimeric mrna is formed containing sequences from a chromosome 22 gene (bcr) at its 5' end and all but the variable exon 1 of c-abl sequence. the product of this mrna, p210bcr-abl, has constitutively high protein-tyrosine kinase activity. we examined k562 cells and other lines established from cml patients for the presence of phosphotyrosine (p-tyr)-containing proteins which ...19921545812
induction by some protein kinase inhibitors of differentiation of a mouse megakaryoblastic cell line established by coinfection with abelson murine leukemia virus and recombinant sv40 retrovirus.mouse c1 line cells are megakaryoblastic cells established by coinfection of abelson murine leukemia virus and recombinant simian virus 40. we examined the effects of various compounds on growth and differentiation of these cells. megakaryocytic differentiation of c1 cells was not induced by cytokines that stimulate megakaryocytic maturation of normal progenitor cells, such as interleukin 3 and 6 and granulocyte-macrophage colony-stimulating factor. however, the cells were induced to differentia ...19911651810
chronic myeloproliferative disease induced by site-specific integration of abelson murine leukemia virus-infected hemopoietic stem cells.we recently showed that hemopoietic stem cells expressing the v-abl oncogene can cause leukemia when injected into lethally irradiated recipient mice. progenitor cells expressing v-abl did not significantly contribute to disease development, and the leukemia was monoclonal in origin. by serially transplanting v-abl-transduced hemopoietic stem cells into normal, nonirradiated syngeneic recipients, we showed that multiple stem-cell clones do exist in some recipients. these cells fluctuated as norm ...19911682923
highly specific characterization of tyrosine phosphoproteins in tumor cells based on monoclonal antibodies defined by conjugated phosphotyramine.phosphotyrosine proteins of four different tumor cell lines were characterized by monoclonal antibodies exhibiting high affinity binding to phosphotyrosine. for the preparation of the antibody-producing mouse hybridoma cell lines we used a novel kind of immunizing antigen with phosphotyramine conjugated directly to carboxylic groups of carrier proteins. screening for high affinity binding antibodies was based on their selective reactivity in immunoprecipitation, affinity chromatography and immun ...19901696448
temperature-sensitive mutants of abelson murine leukemia virus deficient in protein tyrosine kinase activity.the effect of two missense mutations in abl on transformation by abelson murine leukemia virus was evaluated. these mutations led to the substitution of a histidine for tyr-590 and a glycine for lys-536. both changes gave rise to strains that were temperature dependent for transformation of both nih 3t3 cells and lymphoid cells when expressed in the context of a truncated abelson protein. in the context of the prototype p120 v-abl protein, the gly-536 substitution generated a host range mutant t ...19901696637
characterization of flat revertants isolated from cells transformed by abelson murine leukemia virus (ab-mulv).transformed fisher rat fibroblast cell lines by abelson murine leukemia virus frequently revert to the normal phenotype in usual culture conditions. molecular biological analysis of three revertant clones isolated from the transformants showed that their morphological reversions were due to inactivation of the v-abl oncogene at multiple steps including transcription, translation or v-abl protein kinase activity itself without any change in structural gene expression of helper virus. these findin ...19901703165
molecular requirements for the mu-induced light chain gene rearrangement in pre-b cells.during b cell differentiation rearrangement of immunoglobulin (ig) genes is partially regulated by the ig proteins. rearrangement of heavy (h) chain genes is inhibited, whilst that of light (l) chain genes is induced by the membrane form of the mu h chain. in order to analyse additional structural requirements of mu induced l chain gene rearrangement we transfected wild-type mu and mutant mu constructs lacking functional exons encoding the first or second constant domains into abelson murine leu ...19911712291
a poly(da-dt) upstream activating sequence binds high-mobility group i protein and contributes to lymphotoxin (tumor necrosis factor-beta) gene regulation.lymphotoxin (lt; also known as tumor necrosis factor-beta) is a pleiotropic cytokine whose expression is tightly regulated in most cells and is repressed prior to activation signals. in some early b cells and abelson murine leukemia virus-transformed pre-b-cell lines, lt mrna is constitutively expressed. to examine the molecular regulation of the lt gene in a constitutively expressing cell line, we studied the abelson murine leukemia virus-transformed lines pd and pd31. as demonstrated by primer ...19921732752
tumor promoter 12-o-tetradecanoylphorbol-13-acetate and sn-1,2-dioctanoylglycerol increase the phosphorylation of protein kinase c in cells.phosphorylation of protein kinase c (pkc) may be an important mode of regulation of this enzyme that plays a key role in mouse skin tumor promotion and in mammalian cell signal transduction. to investigate this possibility, pkc was specifically immunoprecipitated from abelson murine leukemia virus-transformed normal rat kidney cells that had been metabolically labeled with [32p]orthophosphoric acid. the mr 80,000 phosphoprotein that was specifically immunoprecipitated from abelson murine leukemi ...19911873807
cell surface expression of the short immunoglobulin mu chain (d mu protein) in murine pre-b cells is differently regulated from that of the intact mu chain.pre-b cells carrying djh rearrangements in an appropriate reading frame produce a short mu protein consisting of a djh and the c mu & sequence (d mu protein). we analyzed a d mu-producing abelson-murine leukemia virus-transformed murine pre-b line, 300-19, and demonstrated that d mu proteins are expressed on the cell surface in association with surrogate l chain proteins (lambda 5 and vpreb). however, when we introduced an expression vector coding for the d mu protein into the null pre-b line p1 ...19911904358
identification of a conserved lipopolysaccharide-plus-interleukin-4-responsive element located at the promoter of germ line epsilon transcripts.treatment of splenic b lymphocytes and certain b-lineage cell lines with the mitogen lipopolysaccharide (lps) and the lymphokine interleukin-4 (il-4) induces expression of germ line immunoglobulin c epsilon transcripts and class switching to the c epsilon gene. we show that lps-plus-il-4 induction of germ line epsilon transcripts (termed i epsilon transcripts) occurs at the transcriptional level in an abelson murine leukemia virus-transformed pre-b-cell line. a 1.1-kb region of dna surrounding t ...19911922063
involvement of wild-type p53 in pre-b-cell differentiation in vitro.wild-type p53 protein is a growth modulator whose inactivation has been found to be a key event in malignant transformation. reconstitution of wild-type p53 in the p53-nonproducer, abelson murine leukemia virus-transformed pre-b-cell line l12 gave rise to stably growing clones. wild-type p53-producer derived cell lines exhibit an altered cell cycle, however. more cells with an extended g0/g1 phase were found than in the p53-nonproducer parental cell line. furthermore, when injected into syngenei ...19911924360
deletion mapping of the mouse ornithine decarboxylase-related locus odc-rs8 within igh-v.the odc-rs8 locus belongs to a family of mouse dna sequences related to the gene encoding ornithine decarboxylase (odc). odc-rs8 was mapped by recombinant inbred (ri) strain analysis to the region of chromosome (chr) 12 occupied by the variable region genes of the immunoglobulin heavy chain (igh) complex. in the present study, alleles at odc-rs8 were shown to cosegregate with those for igh variable region (igh-v or vh) genes among 37 inbred mouse strains that had been characterized previously fo ...19921421765
leukemia initiated by hemopoietic stem cells expressing the v-abl oncogene.we report a mouse model with which to study leukemogenesis initiated by a specific genetic change introduced into a primary lymphoid-myeloid pluripotent stem cell. fetal liver hemopoietic cells were infected with a high titer of helper-free abelson murine leukemia virus (a-mulv) and were used to reconstitute lethally irradiated mice. two weeks later, progenies of a single primitive hemopoietic stem cell carrying a specifically integrated a-mulv proviral dna could be detected in both colony-formi ...19911996361
interleukin-7 retroviruses transform pre-b cells by an autocrine mechanism not evident in abelson murine.in this study, we have constructed retroviral vectors expressing the interleukin-7 (il-7) cdna and have used infection with these retroviruses to express this cytokine endogenously in an il-7-dependent pre-b-cell line. infection with il-7 retroviruses, but not with a control retrovirus, resulted in the conversion of the cells to il-7 independence. the frequency at which this occurred, together with data on vector expression levels, indicated that secondary events were required for factor indepen ...19911996110
delay of early b-lymphocyte development by gamma 2b immunoglobulin transgene: effect on differentiation-specific molecules.mice transgenic for gamma 2b ig heavy chain were examined for alterations in b-cell differentiation and endogenous ig gene rearrangement and expression. fresh bone marrow from these mice was markedly reduced in bp-1+ cells and there were small reductions in b220+ and sig+ cells. a-mulv (abelson murine leukemia virus) transformants from these bone marrow cells showed little alteration in ig gene rearrangement and expression when compared to controls, however. isolation of the b-lymphoid compartme ...19901967016
mice homozygous for the ablm1 mutation show poor viability and depletion of selected b and t cell populations.the c-abl gene, originally identified as the cellular homolog of the transforming gene of the abelson murine leukemia virus, encodes a protein-tyrosine kinase of unknown function that is expressed in all mammalian tissues. we have previously described the introduction of a mutation in the c-abl gene into the mouse germline via targeted gene disruption of embryonic stem cells. we now show that mice homozygous for this mutation are severely affected, displaying increased perinatal mortality, runte ...19912065353
normal recombination substrate vh to djh rearrangements in pre-b cell lines from scid mice.to further analyze the vdj recombination defect in lymphoid pre-b cells from mice with severe combined immune deficiency (scid mice), we have assayed the ability of abelson murine leukemia virus (a-mulv) transformed pre-b cells from scid mice to rearrange a recombination substrate in which inverted vh to djh joins activate a selectable (gpt) gene. in unselected populations, substrate rearrangements occurred frequently, but were aberrant and probably analogous to the aberrant rearrangements obser ...19902112584
estimation of d segment usage in initial d to jh joinings in a murine immature b cell line. preferential usage of dfl16.1, the most 5' d segment and dq52, the most jh-proximal d segment.we established spl2-1-2, a murine immature b cell line transformed by tsos-59, a temperature-sensitive mutant of abelson murine leukemia virus. spl2-1-2 has a vhdjh-/g (germ-line) configuration, and can continuously generate d to jh joinings from the germ-line allele during culture. the d to jh joinings are strongly promoted by the shift of the culture temperature from permissive (35 degrees c) to non-permissive temperature (39 degrees c). using this h chain gene rearrangement system, we succeed ...19902110217
novel recombinations of the ig kappa-locus that result in allelic exclusion.allelic exclusion of ig h and l chain gene loci serves to ensure that a b cell expresses a single specificity antibody. the analysis of abelson murine leukemia virus transformed cells that rearrange the kappa-locus during growth in cell culture has provided the opportunity to characterize intermediate steps in ig gene rearrangement. by sequential cloning of an abelson murine leukemia virus transformed cell line we have observed a novel two-step pathway that results in a rearrangement of a v kapp ...19902114448
unlinked regulation of cell growth and differentiation in immature b cell lines.we established many immunoglobulin-null immature b cell lines transformed by tsos-59, a temperature-sensitive mutant of abelson murine leukemia virus. in different cell lines cell growth was depressed and cell differentiation (generation of intracytoplasmic mu-positive cells from ig- cells) was induced by the shift of culture temperature from low (35 degrees c) to high (39 degrees c). cell lines were categorized into four groups: (i) temperature sensitive (ts) to both cell growth and differentia ...19902118832
corrective recombination of mouse immunoglobulin kappa alleles in abelson murine leukemia virus-transformed pre-b cells.previous characterization of mouse immunoglobulin kappa gene rearrangement products cloned from murine plasmacytomas has indicated that two recombination events can take place on a single kappa allele (r. m. feddersen and b. g. van ness, proc. natl. acad. sci. usa 82:4792-4797, 1985; m. a. shapiro and m. weigert, j. immunol. 139:3834-3839, 1987). to determine whether multiple recombinations on a single kappa allele can contribute to the formation of productive v-j genes through corrective recomb ...19902153918
an e mu-v-abl transgene elicits plasmacytomas in concert with an activated myc gene.to clarify how the v-abl oncogene of abelson murine leukemia virus contributes to lymphoid tumorigenesis, we introduced the gene linked to an immunoglobulin heavy chain enhancer (e mu) into the mouse germline. although lymphoid development was not detectably affected in young e mu-v-abl mice, three transgenic lines shared a high predisposition to develop clonal plasmacytomas that secreted iga or igg. the unexpected absence of pre-b lymphomas suggests that abelson virus generates such tumors by i ...19902155783
expression and ontogeny of cd2 on murine b cells.expression of cd2 on developing and mature murine b cells was examined by using an antipeptide antiserum (l50). most ig-bearing splenic b cells were found to express cd2. anti-cd5 and anti-b220 mab divided the peritoneal b cells into two populations expressing high and low levels of these proteins; both populations were found to express uniform levels of cd2. abelson murine leukemia virus-transformed pre-b cell lines derived from fetal liver and adult bone marrow were analyzed to delineate the o ...19901691222
an e. coli expression system for the rapid purification and characterization of a v-abl tyrosine protein kinase.a bacterial expression vector containing a segment of the v-abl gene from abelson murine leukemia virus (a-mulv) was constructed such that the gag region of v-abl was replaced by a sequence encoding the igg-binding domain of the s. aureus protein a. pabl hp, a fusion protein encoded by this vector was rapidly purified to near homogeneity by affinity chromatography on igg-affigel and mono q fplc. the km of the pabl hp kinase for atp varied with [val5]-angiotensin ii concentration and was 21.2 mic ...19902157186
targeted gene disruption of the endogenous c-abl locus by homologous recombination with dna encoding a selectable fusion protein.we have introduced a substitution mutation into the c-abl locus of murine embryonic stem cells by homologous recombination between exogenously added dna and the endogenous gene. model constructs were initially generated that consisted of a promoterless selectable neomycin resistance marker inserted into the v-abl gene of the complete abelson murine leukemia virus genome, designed to be expressed either as a fusion protein or by translational restart. tests of these viral genomes for transmission ...19902183226
abelson murine leukemia virus transforms preneoplastic emu-myc transgene-carrying cells of the b-lymphocyte lineage into plasmablastic tumors.e mu-myc transgenic mice were back-crossed to balb/c mice up to back-cross generation 3. the offspring that included transgene-carrying and -negative mice in approximately equal proportions were randomly divided into 2 groups. thirty-four mice (group i) were treated with pristane, followed by a-mulv, and 40 (group ii) were injected with a-mulv alone. altogether, 16 lymphoid tumors developed in group i and 17 in group ii. nine of the tumors in group i and 4 in group ii appeared as ascitic tumors. ...19902228313
isolation and characterization of flat revertant cell lines from a-mulv-transformed fibroblasts.transformation of lymphoid and fibroblastic cells by abelson murine leukemia virus (a-mulv) is mediated by the viral tyrosine protein kinase. we do not yet know the important target proteins in the cell, the host proteins that modulate the kinase activity, or the host proteins involved in the signal-transduction pathway ultimately leading to altered patterns of cell growth. as a first step toward identifying these host proteins, we have isolated and characterized several flat revertant cell line ...19902157187
v-abl causes hematopoietic disease distinct from that caused by bcr-abl.v-abl, the oncogene transduced by abelson murine leukemia virus, was first characterized by its ability to transform lymphoid cells. bcr-abl, the oncogene formed by a t(9;22) translocation thought to occur in human hematopoietic stem cells, is detectable in almost all cases of chronic myelogenous leukemia (cml), a malignancy of granulocytic cells. bcr-abl also causes a cml-like syndrome in mice whose bone-marrow cells are infected with a retrovirus transducing the gene. more recent reports have ...19911862078
thymic targets for abelson murine leukemia virus are early gamma/delta t lymphocytes.molecular analysis has shown that the majority of abelson murine leukemia virus (ab-mulv)-induced primary thymomas represent transformed gamma/delta thymocytes. many of these thymomas are of monoclonal origin as judged by provirus integration pattern and contain rearranged genes encoding t-cell receptor (tcr) gamma and delta chains but germ-line immunoglobulin heavy-chain genes. some of the monoclonal tumors contain multiple rearranged alleles encoding tcr gamma, delta, and beta chains. further, ...19911827202
induction of chronic myelogenous leukemia in mice by the p210bcr/abl gene of the philadelphia chromosome.in tumor cells from virtually all patients with chronic myelogenous leukemia, the philadelphia chromosome, a fusion of chromosomes 9 and 22, directs the synthesis of the p210bcr/abl protein. the protein-tyrosine kinase activity and hybrid structure of p210bcr/abl are similar to the oncogene product of the abelson murine leukemia virus, p160gag/v-abl, which induces acute lymphomas. to determine whether p210bcr/abl can induce chronic myelogenous leukemia, murine bone marrow was infected with a ret ...19902406902
bcr-abl and bcr proteins: biochemical characterization and localization.the philadelphia translocation results in the expression of a family of chimaeric proteins in which a portion of the bcr protein is fused to c-abl protein. using antibodies which recognize different portions of the bcr gene and abl gene products we have compared the normal bcr products with their chimaeric counterparts. we first conclude that the enhanced kinase activity of the rearranged bcr-abl products (p210 and p190) is recovered almost exclusively from the cytosolic fraction. this methodolo ...19902232885
immature b cells can pass through a vhdjh/germ line state in the ig h chain gene rearrangements.spl2-1-2, an ig- murine immature b cell line, was established by the infection of immature b cells with tsos-59, a temperature-sensitive mutant of abelson murine leukemia virus. southern blot and dna cloning and sequencing analysis showed that spl2-1-2 had a nonproductive vhq52.dsp2.jh3 and a germ line (g) allele (vhdjh-/g), and that d to jh joinings followed by vh to djh joinings progressed on the g allele during culture. these results indicated the existence of novel pathway of igh gene rearra ...19902358678
mechanism of endogenous myc gene down-regulation in e mu-n-myc tumors.transgenic mouse lines carrying the n-myc oncogene deregulated by the immunoglobulin heavy-chain enhancer spontaneously develop b-lymphoid tumors (r. dildrop, a. ma, k. zimmerman, e. hsu, a. tesfaye, r. depinho, and f. w. alt, embo j. 8:1121-1128, 1989; h. rosenbaum, e. webb, j. m. adams, s. cory, and a. w. harris, embo j. 8:749-755). permanent cell lines derived from these tumors (e mu-n-myc cell lines) express extremely high levels of the n-myc transgene but little or no detectable endogenous ...19911986238
phosphotyrosine-containing proteins are concentrated in focal adhesions and intercellular junctions in normal cells.we have used a high-affinity polyclonal antibody directed against phosphotyrosine (p-tyr) to localize p-tyr-containing proteins in normal and transformed cells in culture by immunofluorescence microscopy experiments. the distribution of the proteins with modified tyrosine was compared with that of f-actin in these cells. cells infected with abelson murine leukemia virus were found to contain elevated levels of p-tyr, as expected. various permanent lines of fibroblastic and epithelial cells exhib ...19852413441
cis- and trans-repression of class i major histocompatibility gene expression in abelson virus-transformed murine leukemia.numerous tumor cell lines of leukemic origin are known to modulate cell surface expression of major histocompatibility complex (mhc) class i antigens resulting in alterations in their immune detection and tumorigenicity. we have been studying the mechanisms responsible for attenuation of mhc class i gene expression in an h-2 heterozygous (h-2b x h-2d) abelson-murine leukemia virus (a-mulv)-transformed leukemic cell line (designated r8). here we report that treatment of the r8 cell line with the ...19912070089
direct identification of phosphotyrosine-containing proteins in some retrovirus-transformed cells by use of anti-phosphotyrosine antibody.for direct identification of phosphotyrosine-containing proteins in lysates of various cells, phosphotyrosine (p-tyr) was coupled to carrier proteins and anti-p-tyr antibodies were raised in rabbits and mice. the antibodies were highly specific for p-tyr and did not cross-react with phosphoserine or phosphothreonine. the mean association constant of rabbit anti-p-tyr antibody to n-acetyl-p-tyr was about four times that of rabbit anti-azobenzene phosphonate antibody. in addition, anti-p-tyr antib ...19862416436
the cml-specific p210 bcr/abl protein, unlike v-abl, does not transform nih/3t3 fibroblasts.the v-abl oncogene of the abelson murine leukemia virus (a-mulv) is known to efficiently transform nih/3t3 fibroblasts in vitro and to cause an acute lymphosarcoma in susceptible murine hosts. the role of its relative, the bcr/abl gene product, in the etiology of human chronic myelogenous leukemia (cml) remains speculative. to assess the transforming properties of the bcr/abl gene product, complementary dna clones encoding the cml-specific p210 bcr/abl protein were expressed in nih/3t3 fibroblas ...19872440107
protein phosphorylation at tyrosine residues in v-abl transformed mouse lymphocytes and fibroblasts.phosphotyrosine antibodies were employed to immunodecorate and immunoprecipitate proteins phosphorylated at tyrosine residues in cells transformed by abelson murine leukemia virus (a-mulv). in pre-b and pre-t lymphoma cells transformed by a-mulv, the major phosphotyrosine-containing protein has an mw of 160 kda and shares immunologically detectable sequences with the v-abl oncogene product. moreover, two different proteins of approximately 100 and 68 kda, heavily phosphorylated at tyrosine, were ...19862420727
t-cell receptor and immunoglobulin genes are rearranged together in abelson virus-transformed pre-b and pre-t cells.we have assessed the state of rearrangement and expression of b- and t-cell antigen receptor genes in cells of abelson murine leukemia virus-transformed thymomas and other tumors. we found that unrearranged tcr gamma genes are expressed, as are unrearranged c mu genes, in pre-t, pre-b, and myeloid cells. we also found tcr gamma genes rearranged and expressed in putative pre-t cells and in cells apparently committed to the b-cell lineage. this is in contrast to the data from more mature t- and b- ...19872436035
cyclic amp-modulated potassium channels in murine b cells and their precursors.a voltage-dependent potassium current (the delayed rectifier) has been found in murine b cells and their precursors with the whole-cell patch-clamp technique. the type of channel involved in the generation of this current appears to be present throughout all stages of pre-b-cell differentiation, since it is detected in pre-b cell lines infected with abelson murine leukemia virus; these cell lines represent various phases of b-cell development. thus, the presence of this channel is not obviously ...19872434998
effect of abelson murine leukemia virus on granulocytic differentiation and interleukin-3 dependence of a murine progenitor cell line.the murine diploid hematopoietic cell line 32d cl3 strictly requires interleukin-3 (il-3) for proliferation. when 32d cl3 cells are transferred to il-3-free medium which contains recombinant human granulocyte colony stimulating factor (rhg-csf), the cell number increases four- to five-fold, and after 14 days the whole cell population is differentiated into morphologically normal and myeloperoxidase- and lactoferrin-positive metamyelocytes and granulocytes. infection with abelson murine leukemia ...19872449644
multistage progression of abelson virus-infected murine pre-b-cells to the tumorigenic state.the tumorigenic potential of pre-b-cells at different stages of abelson murine leukemia virus-induced transformation was determined. cell lines with low growth potential in liquid culture were found (a) to have a dose-dependent growth requirement for conditioned medium obtained from bone marrow cultures, (b) to have low colony-forming ability in semisolid medium in the absence of conditioned medium, and (c) to be nontumorigenic when inoculated into syngeneic mice. culture of the factor-dependent ...19902155061
identification of a novel bone marrow-derived b-cell progenitor population that coexpresses b220 and thy-1 and is highly enriched for abelson leukemia virus targets.a novel stage in early b-lymphocyte differentiation has been identified in normal mouse bone marrow cells. earlier work had demonstrated that bone marrow cells characterized by low levels of thy-1 and lack of a panel of lineage markers (thy-1lo lin- cells) were highly enriched for pluripotent hematopoietic stem cells. in this paper, we present evidence that another bone marrow population, which expressed low levels of thy-1 and coexpressed b220, a b-lineage-specific form of the leukocyte common ...19892474759
lupus-related transcript homologous to abelson-murine leukemia virus.in the present study, we found the expression of transcripts homologous to abelson murine leukemia virus (a-mulv) in lupus-prone mice and nonautoimmune mice. one of them, as the lupus-related transcript, is expressed in only lupus-prone mice and induced by bacterial lipopolysaccharide (lsp). we could not induce the transcript by lsp in nonautoimmune mice that we examined. the significance of the transcript autoimmune events in lupus-prone mice is discussed.19882458105
introduction of v-abl oncogene induces monocytic differentiation of an il-3-dependent myeloid progenitor cell line.there are a variety of murine hematopoietic progenitor cell lines which are differentiation arrested, but still require growth factors such as interleukin-3 for their continued growth and survival. while oncogenes such as v-myc and v-abl have been demonstrated to abrogate the requirement for exogenous growth factors, none have been shown to have an effect on the differentiation of these cell lines. in this report, we demonstrate that the introduction and expression of abelson murine leukemia vir ...19902158039
effect of proviral insertion on transcription of the murine b2mb gene.we describe three b2mb mutants caused by integration of retroviral proviruses into the b2m gene. all three insertions occurred within 500 base pairs of each other in the 5' end of the first intron of the b2mb gene. mutant cell line i1 contained a nonfunctional abelson murine leukemia virus-initiated transcript that spliced into b2mb exon ii; mutant cell lines i7 and i18 contained transcripts complementary to b2mb exon 1. both i1 and i7 also contained small amounts of wild-type b2mb transcript. t ...19892542575
multiple steps are required for the induction of tumors by abelson murine leukemia virus.helper virus-free abelson murine leukemia virus (a-mulv) was used to induce monoclonal pre-b-cell tumors in mice. the clonality, patterns of immunoglobulin heavy-chain gene rearrangement, tumorigenicity, and v-abl oncogene expression in individual preleukemic and leukemic colonies were compared. our results indicate that a-mulv preleukemic cells with low or undetectable tumorigenic potential give rise to leukemic cells with high tumorigenic potential by a process of subclone selection. the level ...19892539498
distinct helper virus requirements for abelson murine leukemia virus-induced pre-b- and t-cell lymphomas.abelson murine leukemia virus (a-mulv) can induce pre-b- or t-cell lymphomas (thymomas) in mice depending on the route and time of injection. previous studies have shown that the choice of the helper virus used to rescue a-mulv greatly influences its ability to induce pre-b-cell lymphomas. in this study, we investigated the role of the helper virus in a-mulv-induced thymomas. a-mulv rescued with the helper moloney mulv, balb/c endogenous n-tropic mulv, and two chimeric mulvs derived from these t ...19892539505
synthetic peptides reproducing the egf-receptor segment homologous to the pp60v-src phosphoacceptor site. phosphorylation by tyrosine protein kinases.the octapeptide e-e-k-e-y-h-a-e, corresponding to the amino acid sequence 841-845 of egf receptor, whose tyrosine-845 is homologous to the main phosphorylation site of pp60v-src, has been synthesized together with seven shorter peptides encompassing variable segments around the tyrosine residue. the peptides have been employed as model substrates for inspecting the local structural determinants of three tyrosine protein kinases (tpks), namely; tpk-iib and tpk-iii, isolated from lymphoid cells (e ...19892500978
activation of murine c-abl protooncogene: effect of a point mutation on oncogenic activation.activation of the c-abl protooncogene occurs in abelson murine leukemia virus, in hardy-zuckerman 2 feline sarcoma virus, and during the chromosomal translocations that generate bcr-abl gene fusion products. to study the molecular mechanism involved in the c-abl activation, we have created a series of modifications in murine c-abl and assayed these constructs for oncogenic activity using the nih 3t3 cell transformation assay. our results show that amino-terminal deletions are sufficient for onco ...19902168550
abelson murine leukemia virus induces platelet-derived growth factor-independent fibroblast growth: correlation with kinase activity and dissociation from full morphologic transformation.abelson murine leukemia virus (a-mulv) encodes a single protein product, a tyrosine-specific protein kinase, whose activity is necessary for cell transformation by this retrovirus. using a defined medium culture system, we demonstrate that transformation of nih 3t3 fibroblasts by a-mulv abrogates their normal requirement for platelet-derived growth factor (pdgf) for cell growth. analysis of constructed insertional mutant viruses revealed an absolute correlation between a-mulv-encoded tyrosine ki ...19892538721
n-terminal mutations activate the leukemogenic potential of the myristoylated form of c-abl.the two major forms of the c-abl gene differ from their activated counterpart, the v-abl oncogene of the abelson murine leukemia virus by the replacement of their n-terminal sequences with viral gag sequences. overexpression of p150c-abl type iv in a retroviral vector similar to abelson virus does not transform nih 3t3 fibroblasts, even though it is expressed and myristoylated at levels comparable to pp160v-abl. members of a nested set of deletion mutations of the n-terminus of c-abl type iv in ...19892542016
the accelerating role of abelson murine leukemia virus in murine plasmacytoma development: in vitro infection of spleen cells generates donor-type tumors after transfer to pristane-treated balb/c mice.the role of abelson murine leukemia virus (a-mulv) in the accelerated development of murine plasmacytomas (pcs) (potter et al., 1973: science, 132, 592-594) was studied in a new experimental system. spleen cells from pristane-treated or untreated balb/c mice carrying robertsonian 6;15 fusion chromosomes were infected in vitro with helper-free a-mulv overnight and subsequently transplanted into the peritoneal cavity of pristane-treated or untreated balb/c mice. donor-derived pcs developed in 4 ou ...19892547729
inhibition of tyrosine protein kinases by the antineoplastic agent adriamycin.adriamycin, a lipid-interacting anti-cancer agent, was found to inhibit the phosphorylation of polyglu/tyr (4:1) by tyrosine protein kinases either from spleen or expressed by the oncogene of abelson murine leukemia virus. the dose dependent inhibition by adriamycin is accounted for by competition for the atp binding site, but it is also deeply influenced by the nature and concentration of the phosphorylatable substrate, suggesting multiple interactions with the enzyme. the phosphorylation at ty ...19892543396
t cell receptor dj but not vdj rearrangement within a recombination substrate introduced into a pre-b cell line.to elucidate mechanisms that regulate ordered and tissue-specific assembly of ig and tcr variable region gene segments, we have introduced a recombination substrate comprised of germline tcr beta v, d, and j gene segments into an abelson murine leukemia virus-transformed pre-b cell line that actively rearranges endogenous ig h chain variable region gene segments but does not rearrange endogenous light chain or tcr variable region gene segments. we find that these cells efficiently join d beta se ...19892562155
in vitro immune-receptor gene rearrangements in clonal thymic lymphomas induced by abelson murine leukemia virus.the abelson and moloney murine leukemia virus complex (a-mulv/m-mulv) induces rapidly growing thymic lymphomas following direct injection into the thymus of newborn balb/c and c57bl/6 mice. southern blot analysis with a v-abl specific probe not only demonstrated that primary tumors are clonal, but also that the pattern of a-mulv provirus integration is quite stable in primary tumor cells, as well as in their derived cell lines and clones. most of the cell samples were able to rearrange the immun ...19892554549
dnase i sensitivity of immunoglobulin light chain genes in abelson murine leukemia virus transformed pre-b cell lines.we have used abelson murine leukemia virus (a-mulv) transformed pre-b cell lines to test the hypothesis that the rearrangement potential of a developing b-lymphocyte is dependent on an "opening" of the chromatin structure surrounding immunoglobulin (ig) genes, thus allowing accessibility to an ig gene recombinase. the chromatin structures surrounding heavy (h), kappa (kappa), and lambda (lambda) chain constant-region genes were assessed by dnase i sensitivity in a-mulv transformed cell lines cap ...19892548157
transformation of nih3t3 cells by a-mulv proviral dna: effect of plasmid linearization and carrier dna on transformation efficiency.we have optimized the conditions for efficient nih3t3 focus formation by calcium phosphate transfection of proviral abelson-murine leukemia virus (a-mulv) plasmid dna. linearized pa-mulv, p120 or p160 strains, when transfected with calf thymus carrier dna, will produce 40-50 foci/100 ng pa-mulv without co-transfecting moloney-murine leukemia virus (mo-mulv) plasmid dna.19892554240
reversion to the nontransformed phenotype of abelson murine leukemia virus-transformed cells and their subsequent retransformation.two independent clones of fetal mink lung cells (ccl64) nonproductively transformed by abelson murine leukemia virus (ab-mulv) were used to study spontaneous reversion to the nontransformed phenotype and subsequent retransformation of the revertants. one clone, d62, contained two complete ab-mulv proviruses and expressed polyprotein p120. the other clone, k49, contained four proviruses: three of them were complete and one represented a deletion mutant. in addition to p120, a new polyprotein, p60 ...19862432738
biochemical characterization of a mast cell plasma membrane antigen shared by mouse serosal, culture-derived, and virally transformed mast cells.the expression of the antigenic determinant identified by the b54.2 rat monoclonal antibody on four populations of mouse mast cells has been quantified, and the epitope-bearing surface antigen and its biosynthesis have been characterized. as assessed by indirect immunofluorescence staining and flow cytometric analysis, b54.2 antibody bound to serosal mast cells (s-mc), bone marrow culture-derived mast cells (bm-mc), fetal liver culture-derived mast cells (ftl-mc), and abelson murine leukemia vir ...19872433344
structure and expression of the t cell receptor gamma locus in pre-b and early hemopoietic cells.the genetic structure and expression of the t cell receptor (tcr) loci were examined in pre-b and early hemopoietic cells. thirty-eight percent of abelson murine leukemia virus-transformed pre-b cell lines were rearranged at tcr gamma. moreover, many pre-b cell lines were rearranged at two distinct gamma loci, v gamma 1.2 and v gamma 2. the gamma rearrangements in the pre-b cell lines were similar to those observed previously in t cell lines. v + c-containing gamma mrna was detected in two pre-b ...19892558023
b cell precursors are present in the thymus during early development.an in vitro system for transforming immature lymphoid cells present in the thymus at early development has been established. by phenotype analysis of the transformants obtained, we observed that b cell precursors, susceptible to abelson murine leukemia virus (a-mulv)- or harvey murine sarcoma virus (h-musv)-induced lymphogenesis, were present at high frequency in the fetal thymus of balb/c mice. these precursors recolonized alymphoid thymus lobes in vitro, as do t cell precursors. it was further ...19892784111
preferential proliferation of immature b lineage cells in long-term stromal cell-dependent cultures with il-4.il-4 influences the cellular composition of stromal cell dependent long term cultures. in bone marrow-derived long term lymphoid cultures initiated in presence of il-4, the majority of cells exhibited a more immature phenotype than is usually seen in lymphoid cells grown in whitlock-witte type cultures. this immature cell population, lacking the b220 ag, was purified by cell sorting. when transferred to mixed stromal layers used in conventional lymphoid long term cultures, these cells differenti ...19892783947
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