| protein of macaques against infection with simian type d retrovirus (srv-1) by immunization with recombinant vaccinia virus expressing the envelope glycoproteins of either srv-1 or mason-pfizer monkey virus (srv-3). | rhesus macaques were immunized with live vaccinia virus recombinants expressing the envelope glycoproteins (gp70 and gp22) of simian type d retrovirus (srv), serotype 1 or 3. all of the animals immunized with either the srv-1 env or the srv-3 env vaccinia virus recombinant developed neutralizing antibodies against the homologous srv. in addition, both groups developed cross-reactive antibodies and were protected against an intravenous live-virus challenge with srv-1. the four control animals imm ... | 1992 | 1316495 |
| characterization of t cell epitopes on the envelope glycoprotein of simian retrovirus 1 and 2 (srv-1 and srv-2) in several mouse strains. | various mouse strains were immunized with either srv-1 or srv-2 virus adsorbed on alum. seven to 14 days later spleen cells were removed, and spleen cells were cultured with varying amounts of srv-1 virus and srv-2 virus, or varying amounts of selected srv-1 and srv-2 synthetic envelope peptides to determine their ability to initiate t cell proliferative responses. our studies demonstrated that all mouse strains tested gave strong proliferative responses with srv-2 virus. in contrast, srv-1 viru ... | 1992 | 1378937 |
| studies on a type d retrovirus isolated from an aids patient lymphoma. | the development of aids-related lymphomas (arl) has been on the rise in recent years. during an analysis of arl from aids patients, one individual developed atypical syncytial variants of high-grade burkitt's-type b-cell lymphomas, which prompted further study. however, the search for a hiv-1 retrovirus, which we hypothesized was infecting these cells, led to the subsequent discovery of a type d retrovirus in two early-passage lymphoma cell lines derived from this patient. nucleotide and amino a ... | 1992 | 1381207 |
| the induction of neutralizing antibodies by synthetic peptides of the envelope protein of type d simian retrovirus-1 (srv-1). | it has been recently demonstrated that two serotypes of type d simian retroviruses, namely srv-1 and srv-2, exhibit extensive immunological cross-reactivity but do not exhibit cross-reactivity at the level of neutralizing antibodies. we have also shown recently that an area which includes residues 147-162 of the envelope protein of srv-1 constitutes an epitope to which neutralizing antibodies against srv-1 but not against srv-2 are directed. however, in spite of the capacity of various immunogen ... | 1991 | 1652065 |
| characterization of rhesus macaque b-lymphoblastoid cell lines infected with simian type d retrovirus. | a simian type d retrovirus designated srv induces a fatal immunosuppressive disease in rhesus macaques. this syndrome shows many clinical similarities to acquired immunodeficiency syndrome (aids) in human immunodeficiency virus-infected individuals. to investigate the mechanisms of immune dysfunction in srv infection, we have focused on the interactions of srv serotype 1 (srv-1) with macaque b-lymphoblastoid cell lines (b-lcl). procedures were optimized for establishing b-lcl by immortalization ... | 1991 | 1662056 |
| rna pseudoknots downstream of the frameshift sites of retroviruses. | rna pseudoknot structural motifs could have implications for a wide range of biological processes of rnas. in this study, the potential rna pseudoknots just downstream from the known and suspected retroviral frame-shift sites were predicted in the rous sarcoma virus, primate immunodeficiency viruses (hiv-1, hiv-2, and siv), equine infectious anemia virus, visna virus, bovine leukemia virus, human t-cell leukemia virus (types i and ii), mouse mammary tumor virus, mason-pfizer monkey virus, and si ... | 1991 | 1663382 |
| receptor interference groups of 20 retroviruses plating on human cells. | the types of receptors on the surfaces of human and other mammalian cells for 13 c-type and 7 d-type retrovirus strains were determined by interference to the formation of syncytia and the plating of viral pseudotypes. all the d-type simian retroviruses (srv-1-5, smrv, po-1-lu) share a common receptor which is also utilized by the baboon and cat endogenous c-type viruses (baev, rd114). syncytial cross-interference was also observed in human cells between the gibbon ape leukemia/simian sarcoma as ... | 1990 | 1691887 |
| the use of primers from highly conserved pol regions to identify uncharacterized retroviruses by the polymerase chain reaction. | two degenerate oligonucleotide primers derived from regions of pol conserved among retroviruses have been synthesized. polymerase chain reactions utilizing these primers amplify a 135-bp pol fragment in every retrovirus dna tested to date. the polymerase chain reaction has been linked to a reverse transcriptase step so that a pol-specific dna fragment can be obtained from a moderate amount of a purified retrovirus or viral rna. the identity of an unknown retrovirus can be determined by sequencin ... | 1990 | 1693369 |
| synthetic peptides of envelope proteins of two different strains of simian aids retrovirus (srv-1 and srv-2) represent unique antigenic determinants for serum neutralizing antibodies. | there are at least three distinct serotypes of simian type d retrovirus (srv) which exhibit extensive serological cross-reactivity, but no cross-reactivity exists at the level of serum neutralizing antibodies. amino acid sequence analysis and hydrophobicity plots of srv-1 and srv-2 envelope proteins were compared in order to identify unique potential antigenic determinants to which respective neutralizing antibodies may be directed. peptides representing residues 147-162 of srv-1 and 96-102 of s ... | 1990 | 1701027 |
| immunobiological properties of a recombinant simian retrovirus-1 envelope protein and a neutralizing monoclonal antibody directed against it. | we previously reported that an area encompassing amino acids 147-162 of the envelope region of the simian (type d) retrovirus serotype 1 (srv-1) constitutes an antigenic site for the binding of murine and rhesus neutralizing antibodies. neutralizing antibodies to srv-2 are directed to a different area, encompassing residues 96-102 of srv-2. this paper presents data on the activity of an srv-1 recombinant envelope protein (rep) and of monoclonal hybridoma cell line, c11b8, produced from murine sp ... | 1991 | 1715026 |
| neutralization epitope in the envelope glycoprotein of simian retrovirus-1 (srv-1) and identification of the virus receptor. | we previously demonstrated that the area encompassing residues 147-162 of the envelope protein of simian retrovirus serotype-1 (srv-1) is the target for rhesus anti-srv-1 neutralizing antibodies. a peptide representing amino acids 142-167 of envelope protein (gp70) is capable of inducing virus-neutralizing antibodies in mice. the virus receptor was immunoprecipitated from raji cells using gp70 as the ligand. antibodies to peptide 142-167 inhibit the immunoprecipitation, indicating that the recep ... | 1991 | 1719206 |
| isolation and characterization of the neutralizable epitope of simian retrovirus-1 (srv-1) and of the cell receptor for the virus. | an area encompassing residues 142-167 of the envelope protein of type d simian retrovirus (srv-1) has been shown to contain the epitope to which neutralizing antibodies are directed. this area has been synthesized and shown to bind to monkey and mouse antiviral antibodies and to a virus neutralizing mouse monoclonal antibody. protein conjugates of this peptide as well as the cross-linked or the free peptide induce antibodies capable of neutralizing, in vitro, viral infectivity. the cell receptor ... | 1991 | 1725239 |
| retroviral pseudotypes produced by rescue of a moloney murine leukemia virus vector by c-type, but not d-type, retroviruses. | human hos cells containing a moloney murine leukemia virus (mo-mlv) recombinant genome were infected by a panel of retroviruses. the c-type viruses simian sarcoma associated virus, feline leukemia virus subgroup b, and the feline endogenous virus rd114 were able to form pseudotypes with the mo-mlv genome, which transferred a selectable marker gene to target cells; however, human t cell leukemia virus-1 and the d-type viruses mason-pfizer monkey virus and simian retrovirus-1 failed to rescue the ... | 1992 | 1733113 |
| use of molecular cloned viral genomes for studies into interrelationship between type d retroviruses from monkey and human cells. | type d retroviruses constitute a group of rna tumor viruses so far isolated exclusively from primates. 4 groups of isolates are known to date (mason-pfizer virus, agents of simian acquired immunodeficiency syndrome--saids, endogenous viruses of old world and new world monkeys, and some isolates from cell lines--pmf virus). the members of the latter group are well characterized at protein-chemical and immunological levels. briefly described in this paper are the results of our studies into the mo ... | 1990 | 2129382 |
| nucleotide sequence of mason-pfizer monkey virus: an immunosuppressive d-type retrovirus. | the genetic structure of mason-pfizer monkey virus (mpmv), a d-type retrovirus, has been determined. in addition to the viral gag, pol, and env genes is an orf overlapping both gag and pol and that encodes the viral protease. surprisingly, the mpmv env protein is highly homologous to that of the avian c-type virus, reticuloendotheliosis associated virus rev-a. the env sequence encodes an immunosuppressive peptide, which suggests that mpmv, like rev-a, may transiently induce a t-suppressor cell p ... | 1986 | 2421920 |
| sequence relationships of type d retroviruses which cause simian acquired immunodeficiency syndrome. | simian acquired immunodeficiency syndrome (saids) in macaque monkeys is caused by type d retroviruses; three independent virus isolates are identified as srv-1 (saids retrovirus-serotype 1), srv-2, and mpmv (mason-pfizer monkey virus). virions from these three isolates have serologically related core antigens, but distinct surface proteins. also, srv-2 is unique since it apparently induces retroperitoneal fibromatosis in addition to saids. the complete dna sequence of molecularly cloned srv-2 is ... | 1987 | 2435057 |
| characterization of a synthetic envelope peptide of srv-1 and srv-2 virus that specifically binds rhesus anti-srv-1 and anti-srv-2 neutralizing antibodies. | | 1989 | 2481957 |
| asymptomatic infection of the central nervous system by the macaque immunosuppressive type d retrovirus, srv-1. | the aetiological agent of spontaneously occurring simian acquired immune deficiency syndrome (saids) in rhesus monkeys (macaca mulatta) at the california primate research center is a type d retrovirus designated saids retrovirus serotype 1 (srv-1). srv-1 dna and rna have previously been detected in the brains of rhesus monkeys with saids in the absence of viral antigen or neuropathological lesions. in this study we further define the relationship between srv-1 and the central nervous system (cns ... | 1989 | 2544658 |
| infection of macaque monkeys with simian immunodeficiency virus from african green monkeys: virulence and activation of latent infection. | the virulence of three isolates of simian immunodeficiency virus from african green monkeys (sivagm) was studied in rhesus and pigtailed macaques. none of 15 rhesus monkeys and one of four pigtailed monkeys died from infection during the time they were studied (up to 33 months). sivagm was only isolated from rhesus monkeys for up to 2 months after inoculation. however, when these animals were secondarily infected with simian acquired immunodeficiency syndrome retrovirus type 1 (srv-1), sivagm wa ... | 1989 | 2547960 |
| [simian aids virus: review]. | the review article on simian aids viruses compiles the presently known facts of aids-related simian retroviruses causing immunodeficiencies or lymphomas in nonhuman primates. they are also compared to the situation in man. simian acquired immunodeficiencies or lymphoproliferative diseases can be caused by infectious (exogenous) oncoviruses (c- or d-type) or by lentiviruses. infectious d-type oncoviruses of simian origin are: mason-pfizer monkey virus (mpmv), simian retrovirus type 1 (srv-1), sim ... | 1989 | 2559560 |
| serological survey for viral diseases in the cayo santiago rhesus macaque population. | the free-ranging population of rhesus monkeys (macaca mulatta) on cayo santiago was sero-surveyed for human measles, simian virus 40, b virus (herpes simiae), rhesus cytomegalovirus, human and simian retroviruses and encephalomyocarditis virus to determine the prevalence of these viruses in the colony. the results of this study indicate that the colony is free of sv40, htlviii (hiv-1), stlviii (siv) and srv1; has a low prevalence of measles and emcv; and high prevalence rates for b virus, cmv an ... | 1989 | 2571176 |
| evaluation of type d retroviruses as diagnostic tools in hiv infections. | a type d retrovirus isolated from a permanent human cell line (pmfv) was employed as diagnostic reagent both in southern transfer hybridization experiments using the cloned genome as a probe and in immunoblot analysis using sds disrupted virus particles. hybridization experiments performed under conditions of different stringencies revealed a close homology of pmfv to saids type d retroviruses of serotype 1 (srv-1, saids retrovirus d/ne), a related homology to the prototype type d virus (mpmv) a ... | 1989 | 2619725 |
| molecular cloning of a type d retrovirus from human cells (pmfv) and its homology to simian acquired immunodeficiency type d retroviruses. | unintegrated circular proviral dna of a type d retrovirus (pmfv) isolated from a permanent human cell line was molecularly cloned in the bacteriophage vector l47.1 and subcloned in the plasmid vector pgem-2. a restriction endonuclease map of pmfv dna was established using 10 different enzymes for single and multiple digestions of closed circular and cloned dna molecules. by restriction endonuclease analysis cloned pmfv dna represented full-length viral dna with one long terminal repeat (ltr). th ... | 1989 | 2815583 |
| nucleotide sequence of srv-1, a type d simian acquired immune deficiency syndrome retrovirus. | simian acquired immune deficiency syndrome (saids) in the macaque genus of monkeys at the california primate research center is apparently caused by infection by a type d retrovirus. the complete nucleotide sequence (8173 base pairs) of a molecular clone of the prototype saids virus isolate, srv-1, reveals a typical retrovirus structure with long terminal repeats (346 base pairs) and open reading frames for the gag (663 codons), pol (867 codons), and env (605 codons) genes. srv-1 also has a sepa ... | 1986 | 3006247 |
| the causes of false-positives encountered during the screening of old-world primates for antibodies to human and simian retroviruses by elisa. | sera from 526 old-world primates representing 50 different species were screened by elisa for antibodies to human t-lymphotropic viruses i and iii, and simian retrovirus type 1 (srv-1). about one-fourth of the sera were positive by elisa. there was a tendency, however, for the same sera to be positive for all three human and simian retroviruses. only about one in five of the elisa antibody-positive sera were confirmed to be positive by western blotting. false-positive elisa antibody tests were p ... | 1986 | 3025237 |
| nucleotide sequence of a complete mouse intracisternal a-particle genome: relationship to known aspects of particle assembly and function. | the 7,095-nucleotide sequence of a mouse genomic intracisternal a-particle (iap) element, mia14, is reported. mia14 is known to be colinear with iap 35s rna and to contain functional long terminal repeats. its internal genetic organization was determined by comparisons with a homologous syrian hamster element and the related retroviruses simian retrovirus 1 (simian type d) and rous sarcoma virus (avian type c). mia14 contains a gag-protease open reading frame of 827 codons and a pol region of 86 ... | 1987 | 3041022 |
| induction of simian acquired immune deficiency syndrome (saids) with a molecular clone of a type d saids retrovirus. | we have isolated a molecular clone of the full-length integrated provirus of simian acquired immune deficiency syndrome retrovirus serotype 1 (srv-1) from a fatal case of simian acquired immune deficiency syndrome in a juvenile rhesus macaque. an integrated srv-1 provirus was cloned, sequenced, and found to contain four large open reading frames encoding gag-precursor protein, protease, polymerase, and envelope. the proviral clone was transfected into d17 canine osteosarcoma cells and found to p ... | 1987 | 3041028 |
| distribution of a macaque immunosuppressive type d retrovirus in neural, lymphoid, and salivary tissues. | simian acquired immune deficiency syndrome (saids) in rhesus macaques (macaca mulatta) at the california primate research center is caused by a type d retrovirus designated saids retrovirus serotype 1 (srv-1). this syndrome is characterized by profound immunosuppression and death associated with opportunistic infections. neurologic signs and lesions have not been described as part of this syndrome. the distribution of srv-1 in the salivary glands, lymph nodes, spleens, thymuses, and brains of ei ... | 1988 | 3285033 |
| mesenchymal neoplasms associated with type d retroviruses in macaques. | the type d subfamily of retroviruses contains five distinct viruses which are found in new and old world monkeys. the retroviruses found in old world macaque (genus macaca) monkeys are exogenous to the species and upon injection induce a fatal simian acquired immune deficiency syndrome (saids). two serotypes of type d virus, saids retrovirus types 1 and 2 (srv-1 and srv-2), are found in captive macaques in primate centres in the united states. in addition to saids, two neoplasms, retroperitoneal ... | 1987 | 3319133 |
| natural history of endemic type d retrovirus infection and acquired immune deficiency syndrome in group-housed rhesus monkeys. | a 2.5-year epidemiologic study of a breeding group of rhesus monkeys (macaca mulatta), which is a focus of endemic simian acquired immunodeficiency syndrome (saids), demonstrated a strong association between the occurrence of saids and infection with a type d retrovirus, saids retrovirus serotype 1 (srv-1). of 23 healthy "tracer" juvenile rhesus monkeys, 19 (83%) died with saids within 9 months of introduction into the resident saids-endemic population. in contrast, 21 healthy "sentinel" juvenil ... | 1987 | 3477665 |
| viremia, antigenemia, and serum antibodies in rhesus macaques infected with simian retrovirus type 1 and their relationship to disease course. | the course of simian retrovirus type 1 (srv-1) infection was studied in 14 experimentally inoculated juvenile rhesus monkeys. viral transmembrane protein antigenemia and antibodies to whole virus were measured by enzyme linked immunosorbent assay and correlated with the clinical course of disease and virus isolation. based on these parameters, animals with simian retrovirus type 1-induced disease were divided into three categories: monkeys dying within a few months of fulminating simian acquired ... | 1987 | 3599907 |
| pathogenesis of simian aids in rhesus macaques inoculated with the srv-1 strain of type d retrovirus. | type d retrovirus was isolated from rhesus macaques with simian acquired immunodeficiency syndrome (saids) and transmitted to healthy rhesus macaques with tissue culture medium containing the virus. the clinical, immunologic, and lymph node morphologic changes were observed in 9 rhesus macaques for 52 weeks after inoculation. a spectrum of clinical signs developed including early death, persistent saids, and apparent remission. animals that died or developed persistent saids had characteristic l ... | 1986 | 3963589 |
| lesions of gnotobiotic calves experimentally infected with a calicivirus-like (newbury) agent. | fourteen gnotobiotic calves were killed 0.5 to ten days after infection with newbury agent srv-1 and the changes in small intestinal structure and function were assessed, qualitatively and quantitatively, by light microscopy, scanning and transmission electron microscopy, enzymology and xylose absorption. the first enterocytes detected as infected by immunoperoxidase were those on the sides of villi at the base. subsequently exfoliation of degenerate enterocytes resulted in stunted villi; mucosa ... | 1984 | 6328722 |
| localisation of enteropathogens in paraffin embedded tissue by immunoperoxidase. | an indirect immunoperoxidase technique has been used to identify enteropathogens in formol-sublimate fixed paraffin embedded sections of calf intestine. infections with bovine rotavirus, bovine coronavirus, newbury agent srv -1, and k99+ escherichia coli have been detected in the intestines from experimentally infected and conventially reared diarrhoeic or normal calves. the ability to visualize enteropathogenic agents in histological sections resulted in the demonstration of virus infected cell ... | 1984 | 6373836 |
| characterization of a calici-like virus (newbury agent) found in association with astrovirus in bovine diarrhea. | a bovine calici-like virus and astrovirus, present in the same fecal sample from an outbreak of diarrhea, were separated from each other by calf passage. the calici-like virus (newbury agent srv-1) caused anorexia, diarrhea, and xylose malabsorption in gnotobiotic calves aged 17 to 60 days, whereas the bovine astrovirus was nonpathogenic in similar calves. the calici-like virus was shown to be antigenically distinct from a previously described isolate (newbury agent srv-2) by two-way cross-prote ... | 1984 | 6418656 |
| analysis of the role of the pseudoknot component in the srv-1 gag-pro ribosomal frameshift signal: loop lengths and stability of the stem regions. | the simian retrovirus-1 (srv-1) gag-pro frameshift signal was identified in previous work, and the overall structure of the pseudoknot involved was confirmed (ten dam e, brierley i, inglis s, pleij c, 1994, nucleic acids res 22:2304-2310). here we report on the importance of specific elements within the pseudoknot. some mutations in stem s1 that maintain base pairing have reduced frameshift efficiencies. this indicates that base pairing in itself is not sufficient. in contrast, frameshifting cor ... | 1995 | 7585244 |
| characterization of infectious type d retrovirus from baboons. | infectious virus resembling type d simian retrovirus (srv) was isolated from ethiopian baboons (papio cynocephalus) (srv-pc) housed at the university of washington regional primate research center. when baboon peripheral blood mononuclear cells (pbmc) or tissues were cocultured with the h-9 human t-cell line or the raji human b-cell line, large multinucleated syncytia positive for srv-2 antigens were observed microscopically. immunoblot analysis of purified srv-pc from cell culture supernatants ... | 1995 | 7871741 |
| continuous propagation of rre(-) and rev(-)rre(-) human immunodeficiency virus type 1 molecular clones containing a cis-acting element of simian retrovirus type 1 in human peripheral blood lymphocytes. | molecular clones of human immunodeficiency virus type 1 that contained either 37 point mutations in the rev-responsive element (rre) that did not affect the overlapping env reading frame or both a mutated rre and two mutations that eliminated rev were constructed. the mutations in the rre were shown to remove both negative and rev-inducible positive effects of the rre on gene expression (g. nasioulas, a. s. zolotukhin, c. tabernero, l. solomin, c. p. cunningham, g. n. pavlakis, and b. k. felber, ... | 1994 | 7966585 |
| identification and analysis of the pseudoknot-containing gag-pro ribosomal frameshift signal of simian retrovirus-1. | the pro and pol genes of simian retrovirus-1 (srv-1) are expressed as parts of a fusion protein generated by -1 ribosomal frameshifting. to investigate the requirements for frameshifting at the gag-pro overlap, we have inserted a stretch of 58 nucleotides containing the proposed frameshift signal into a plasmid that allows monitoring of translation in all three reading frames. in vitro translation of mrnas derived from this plasmid indicated that the 58 nucleotides from the srv-1 gag-pro overlap ... | 1994 | 8036158 |
| langerhans cells in oral mucosa of rhesus monkeys before and after infection by simian retrovirus-1 and simian immunodeficiency virus. | to study the influence of experimental infection with simian retrovirus-1 and simian immunodeficiency virus on the number and distribution of langerhans cells in oral mucosa of rhesus monkeys, 10 monkeys were intravenously inoculated with simian retrovirus-1, 7 with simian immunodeficiency virus, and 2 were mock-inoculated. biopsies were taken from gingiva and cheek pouch before infection and at 1 (simian immunodeficiency virus group only), 4, and 7 months after infection. langerhans cells were ... | 1993 | 8284080 |
| the posttranscriptional control element of the simian retrovirus type 1 forms an extensive rna secondary structure necessary for its function. | it was previously shown that a 240-nucleotide (nt) rna element (cis-acting transactivation element [cte]) located between the env gene and the 3' long terminal repeat of simian retrovirus type 1 (srv-1) can functionally replace posttranscriptional activation directed by rev and the rev-responsive element (rre) when inserted into a rev- and rre-deficient molecular clone of human immunodeficiency virus type 1, resulting in efficient virus replication. here, we analyze the molecular and structural ... | 1996 | 8709222 |
| role of mason-pfizer monkey virus (mpmv) constitutive transport element (cte) in the propagation of mpmv vectors by genetic complementation using homologous/heterologous env genes. | to study mason-pfizer monkey virus (mpmv) replication over a single round, virus particles were generated that contain a replication-defective vector encoding a dominant selectable marker, the hygromycin b phosphotransferase (hyg) gene. genetic complementation with a homologous mpmv envelope glycoprotein (env-gp) or pseudotyping by several heterologous env-gps from a variety of viruses resulted in infectious mpmv particles containing the replication-defective rna. recently, it has been shown tha ... | 1996 | 8874512 |
| the history of simian aids. | retrospective data indicate that two separate outbreaks of simian aids and associated lymphoma were caused by simian immunodeficiency virus (sivmac and sivstm, respectively) in group-housed macaques at the california regional primate research center (crprc) in the early and mid-1970s. because these epizootics were not then recognized as infectious in nature, surviving healthy siv carriers were sent to other primate centers where they transmitted the viruses to resident macaques. the source of si ... | 1996 | 8892035 |
| complete nucleotide sequence of simian endogenous type d retrovirus with intact genome organization: evidence for ancestry to simian retrovirus and baboon endogenous virus. | a complete endogenous type d viral genome has been isolated from a baboon genomic library. the provirus, simian endogenous retrovirus (serv), is 8,393 nucleotides long and contains two long terminal repeats and complete genes for gag, pro, pol, and env. the primer binding site is complementary to trna(lys)3, like in lentiviruses. the env gp70 protein is highly homologous to that of baboon endogenous virus (baev). pcr analysis of primate dna showed that related proviral sequences are present in o ... | 1997 | 9094640 |
| identification and purification of cellular proteins that specifically interact with the rna constitutive transport elements from retrovirus d. | human immunodeficiency virus (hiv) encodes a transacting protein, rev, which interacts with an rna element (rre) to mediate nuclear export of unspliced viral mrna. recently, the rna constitutive transport elements (cte) from mason-pfizer monkey virus (mpmv) and simian retrovirus type i (srv-1) were shown to render rev-independent expression of gag, pol, or env genes in subgenomic constructs of hiv-1 and to support replication of hiv-1 mutants lacking rre and rev. since ctes act in cis, in the ab ... | 1997 | 9123840 |
| replacement of posttranscriptional regulation in sivmac239 generated a rev-independent infectious virus able to propagate in rhesus peripheral blood mononuclear cells. | lentiviruses control virion production via posttranscriptional regulation mediated by the viral rev protein. in this study, we demonstrate that the rev regulation of sivmac239 can be replaced by the presence of the cis-acting transport element (cte) of the type d simian retroviruses 1 (srv-1). to avoid the possibility of generating revertants, the rev-independent siv clones have both rev and the rev responsive element (rre) destroyed by multiple point mutations that do not affect the overlapping ... | 1997 | 9191842 |
| base-pairings within the rna pseudoknot associated with the simian retrovirus-1 gag-pro frameshift site. | frameshift and readthrough sites within retroviral messenger rnas are often followed by nucleotide sequences that have the potential to form pseudoknot structures. in the work presented here, nmr methods were used to characterize the base-pairings and structural features of the rna pseudoknot downstream of the gag-pro frameshift site of simian retrovirus type-1 (srv-1) and a functional mutant of the srv-1 pseudoknot. evidence is presented that these pseudoknots contain two a-form helical stems o ... | 1997 | 9237911 |
| the simian retrovirus-1 constitutive transport element, unlike the hiv-1 rre, uses factors required for cellular mrna export. | a hallmark of retroviral gene expression is that unspliced retroviral genomic rna is exported to the cytoplasm, whereas endogenous intron-containing cellular rnas are usually retained in the nucleus. in complex retroviruses, such as human immunodeficiency virus-1 (hiv-1), nuclear export is accomplished by the interaction of a virally encoded protein, rev, with a cis-acting rna element, the rev-responsive element (rre). in type d retroviruses, such as the simian retrovirus type 1 (srv-1), however ... | 1997 | 9285715 |
| dna immunization of mice against sivmac239 gag and env using rev-independent expression plasmids. | simian immunodeficiency virus (siv) structural gene expression, including gag and env, strictly depends on the interaction of the viral posttranscriptional regulator rev with its target rna, the rev-responsive element (rre). a small rna element, termed the constitutive transport element (cte), located in the 3' portion of simian retrovirus 1 (srv-1) mrna, can efficiently substitute for the human immunodeficiency virus (hiv) rev-rre interaction, and thus render hiv expression and replication rev ... | 1998 | 9453255 |
| mutational analysis of the rna pseudoknot involved in efficient ribosomal frameshifting in simian retrovirus-1. | mutational effects on frameshifting efficiency of the rna pseudoknot involved in ribosomal frameshifting in simian retrovirus-1 (srv-1) have been investigated. the primary sequence and the proposed secondary structure of the srv-1 pseudoknot are similar to those of other efficient frameshifting pseudoknots in mouse mammary tumor virus (mmtv) and feline immunodeficiency virus (fiv), where an unpaired adenine nucleotide intercalates between stem 1 and stem 2. in srv-1 pseudoknot, the adenine nucle ... | 1998 | 9490779 |
| simian retrovirus receptor and neutralization mechanism by antibodies to the envelope glycoprotein. | type d simian retroviruses (srv) cause an acquired immunodeficiency syndrome (aids) in monkeys. results of infection with srv range from complete recovery with absence of viremia to a viremic state, which produces aids-like symptoms and culminates in death. these varied outcomes render the interaction of the host and srv an attractive model for the study of immunosuppressive retrovirus resulting in different pathologic consequences. we describe here the isolation and determination of the molecul ... | 1999 | 10333242 |
| equilibrium unfolding pathway of an h-type rna pseudoknot which promotes programmed -1 ribosomal frameshifting. | the equilibrium unfolding pathway of a 41-nucleotide frameshifting rna pseudoknot from the gag-pro junction of mouse intracisternal a-type particles (miap), an endogenous retrovirus, has been determined through analysis of dual optical wavelength, equilibrium thermal melting profiles and differential scanning calorimetry. the miap pseudoknot is an h-type pseudoknot proposed to have structural features in common with the gag-pro frameshifting pseudoknots from simian retrovirus-1 (srv-1) and mouse ... | 1999 | 10373368 |
| modified human immunodeficiency virus-based lentiviral vectors display decreased sensitivity to trans-dominant rev. | as a first step toward the development of hiv-based conditionally replicating defective interfering particles expressing trans-dominant rev (tdrev), we studied whether mutation of the splicing signals and replacement of the rre by the srv-1 cte would render these vectors less sensitive to tdrev. vectors with mutations in the splicing signals (sd-/rre+) yielded high titers (5 x 10(6) cfu/ml) and showed higher levels of cytoplasmic unspliced mrna than the corresponding sd+/rre+ vectors either in t ... | 2000 | 10779166 |
| human spontaneous laryngeal carcinoma hep-2 cells are chronically infected with srv-1 virus, a variant of simian type d retrovirus. | a type d retrovirus chronically persisting in hep-2 cells from human laryngeal carcinoma was analyzed by pcr and sequenced. this virus is most similar to srv-1 and probably represents one of its subtypes. | 2000 | 11022257 |
| differential susceptibility of retroviruses to nucleoside analogues. | retroviruses may cause diseases in their vertebrate hosts. they are distinguished by their common means of replication involving reverse transcription, a process inhibited by nucleoside reverse transcriptase inhibitors (nrtis) and other compounds used in antiretroviral chemotherapy. previous work on nrtis has been limited to their effect on human immunodeficiency virus (hiv) (for review see ho & hitchcock, 1989; weller, 1999) and little information exists regarding the efficacy and therapeutic p ... | 2001 | 11527046 |
| ribosomal pausing at a frameshifter rna pseudoknot is sensitive to reading phase but shows little correlation with frameshift efficiency. | here we investigated ribosomal pausing at sites of programmed -1 ribosomal frameshifting, using translational elongation and ribosome heelprint assays. the site of pausing at the frameshift signal of infectious bronchitis virus (ibv) was determined and was consistent with an rna pseudoknot-induced pause that placed the ribosomal p- and a-sites over the slippery sequence. similarly, pausing at the simian retrovirus 1 gag/pol signal, which contains a different kind of frameshifter pseudoknot, also ... | 2001 | 11713298 |
| the endogenous langur type d retrovirus po-1-lu and its exogenous counterparts in macaque and langur monkeys. | po-1-lu, the endogenous type d retrovirus of langurs (trachypithecus obscurus) has previously been considered a progenitor to the prototype type d retrovirus, mason pfizer monkey virus (m-pmv/srv-3), that became established in macaque monkeys (macaca spp.) following a zoonosis. this study reevaluates this hypothesis to include other exogenous srvs. new sequence information from the gp70(su)-encoding region of po-1-lu shows striking similarity to the newly identified exogenous langur retrovirus, ... | 2003 | 14585330 |
| intestinal stromal tumors in a simian immunodeficiency virus-infected, simian retrovirus-2 negative rhesus macaque (macaca mulatta). | multifocal submucosal stromal tumors were diagnosed in a 5.5-year-old rhesus macaque (macaca mulatta) experimentally infected with simian immunodeficiency virus, strain sivsme660, and cd4+ t cell depleted. the animal was negative for simian retroviruses, srv-1, -2, and -5. polymerase chain reaction analysis of dna from tumor and spleen tissue revealed abundant, preferential presence of retroperitoneal fibromatosis herpesvirus, the macaque homologue of the kaposi sarcoma-associated herpesvirus (h ... | 2005 | 15872392 |
| effect of posttranscriptional regulatory elements on transgene expression and virus production in the context of retrovirus vectors. | ineffective transgene expression in a sufficient amount of target cells is still a limitation in retroviral vector mediated gene therapy. thus, we systematically evaluated four genetic modulators, (i) the woodchuck posttranscriptional regulatory element (wpre), (ii) the mouse rna transport element (rte), (iii) the constitutive transport element (cte) of the simian retrovirus type 1 (srv-1), and (iv) the 5' untranslated region of the human heat shock protein 70 (hsp70 5'utr), all of them involved ... | 2005 | 16054668 |
| new simian beta retroviruses from rhesus monkeys (macaca mulatta) and langurs (semnopithecus entellus) from rajasthan, india. | natural infection of feral indian rhesus monkeys (macaca mulatta) by a new simian beta retrovirus, provisionally called simian retrovirus-7 (srv-7) is described. the virus is capable of in vitro replication in primary human peripheral blood lymphocytes (pbl) and b and t cell lines. we have earlier reported a novel srv, srv-6 from indian langurs (semnopithecus entellus). additional sequence analyses from gp20 transmembrane (tm) env genes of srv-6 and srv-7 place them in a separate cluster, relate ... | 2006 | 16791425 |
| development of real-time pcr assays for quantitation of simian betaretrovirus serotype-1, -2, -3, and -5 viral dna in asian monkeys. | simian betaretroviruses (srv), formerly known as simian type d retroviruses, are endemic in many populations of asian monkeys of the genus macaca. asian monkeys have been used extensively as animal models for preclinical hiv vaccine development, therapeutics, and other biomedical studies. srv infection can sometimes lead to immune deficiency disease, which complicates such studies; thus, it is important to screen for srv infection and remove infected animals from test populations. real-time pcr ... | 2008 | 18597861 |
| comprehensive in vitro analysis of simian retrovirus type 4 susceptibility to antiretroviral agents. | simian retrovirus type 4 (srv-4), a simian type d retrovirus, naturally infects cynomolgus monkeys, usually without apparent symptoms. however, some infected monkeys presented with an immunosuppressive syndrome resembling that induced by simian immunodeficiency virus infection. antiretrovirals with inhibitory activity against srv-4 are considered to be promising agents to combat srv-4 infection. however, although some antiretrovirals have been reported to have inhibitory activity against srv-1 a ... | 2013 | 23365453 |
| a novel simian retrovirus subtype discovered in cynomolgus monkeys (macaca fascicularis). | a new simian retrovirus (srv) subtype was discovered in china and the usa from cambodian-origin cynomolgus monkeys. histopathological examination from necropsied animals showed multifocal lymphoplasmacystic and histocytic inflammation. the complete genome sequences demonstrated that the us virus isolates were nearly identical (99.91-99.93 %) and differed only slightly (99.13-99.16 % identical) from the china isolate. phylogenetic analysis showed that the new virus isolates formed a distinct bran ... | 2016 | 27609630 |