Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Genes, src”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources
PubMed1979

Heterogeneity of genetic loci in chickens: analysis of endogenous viral and nonviral genes by cleavage of DNA with restriction endonucleases.

Restriction endonucleases can be used to define the structure and position of genetic loci for which specific molecular hybridization reagents are available. We have used this approach to compare 18 chicken embryos with respect to several cellular genes; endogenous viral DNA related to the replicative genes of avian sarcoma virus (ASV) or to RAV-O, an endogenous virus of chickens; and sequences related to the transforming (src) gene of ASV. Each cellular gene eas remarkably homogeneous within our test population. We found little or no variation in globin and ovomucoid genes; ovalbumin and transferrin (with one exception) showed variation which is probably allelic in nature. The endogenous viral DNA which has homology with RAV-O was found at several different positions in host DNA and its structure resembled that of proviruses acquired by experimental infection, with sequences from both ends of viral RNA repeated near both ends of viral DNA. Within the population of 18 chickens, one endogenous provirus was always present, whereas the several other proviruses were each found in only a few members of this group. However, screening of additional chickens identified individuals lacking the provirus common to the initial 18 animals surveyed; in at least one embryo no RAV-O-related DNA was detected. These findings suggest that the endogenous RAV-O-related sequences have entered the germ line by relatively recent infection and are still segregating in several contemporary chicken flocks. The sequences in the chicken genome which have homology with the src gene of ASV are invariant from bird to bird and in this sense resemble a cellular gene rather than a viral sequence.

Alpharetrovirus↗
PubMed1979

Characterization of some isolates of newly recovered avian sarcoma virus.

We previously reported the isolation of a newly recovered avian sarcoma virus (rASV) from tumors of chickens injected with transformation-defective (td) mutants of the Schmidt-Ruppin strain of Rous sarcoma virus (SR-RSV). In this paper, we present further biological and biochemical characterization of the recovered sarcoma viruses. High titers of rASV's were generally obtained by cocultivation of tumor cells with normal chicken embryo fibroblasts or by homogenization of tumor tissues. Most rASV isolates were similar to SR-RSV, subgroup A (SR-RSV-A), in their growth characteristics and were nondefective in replication. The subgroup specificity of rASV's and the electrophoretic mobilities of their structural proteins were the same as those parental td viruses. The nondefectiveness of rASV's was further substantiated by the size of their genomic RNA, which was indistinguishable from that of SR-RSV-A and substantially larger than that of parental td RNA. Molecular hybridization using complementary DNA specific to the src gene of SR-RSV (cDNAsrc) showed that the RNAs of td mutants used in this study contained extensive deletions within the src gene (7 to 30% hybridization with cDNAsrc); the same probe hybridized up to 90% with RNA from two isolates of rASV. These data indicate that rASV has regained genetic information which had been deleted in the td mutants and strongly suggest that the generation of rASV involves a genetic interaction between td virus and host cell genetic information.

Alpharetrovirus↗
PubMed1987

Analysis of p60v-src mutants carrying lesions involved in temperature sensitivity.

Analysis of the src genes of three temperature-sensitive (ts) mutants of Rous sarcoma virus (tsNY68, tsNY72-4, and PA104) showed that each has two C-terminal mutations in the kinase domain required for temperature sensitivity, as assayed by morphological alteration and anchorage-independent growth. In all three mutants, one of the mutations is a valine-to-methionine change at position 461. To assess the contribution of each mutation to the biochemical properties of the src protein, we analyzed the kinase activity and the interaction with cellular proteins p50 and p90 of recombinant src gene products in which only one mutation was combined with wild-type src sequences. Chimeric src protein containing only the Met-461 mutation was indistinguishable from the wild type by all criteria examined, while the effect of the second C-terminal mutation alone varied with the defectiveness of the parental ts mutant. The second mutation alone, while not sufficient to cause ts transformation, altered p60src complex formation with cellular proteins p50 and p90 and altered the in vitro thermolability of src kinase activity. The results indicate that these biochemical properties of p60src are more sensitive to mutation than others, such as in vivo kinase activity, which require more profound structural alterations.

Animals↗
PubMed1992

Small deletion in v-src SH3 domain of a transformation defective mutant of Rous sarcoma virus restores wild type transforming properties.

RSV mutant virus PA101T was obtained while assaying the tumorigenicity of parental PA101 virus in chickens. PA101 is a transformation defective mutant of RSV which has a low src kinase activity. However, PA101 retained a temperature-sensitive ability to induce sustained proliferation of neuroretina cells. PA101T appeared as a wild-type phenotype revertant of PA101. Molecular cloning and sequencing of PA101T showed that this reversion is due to additional mutations in PA101 src gene. These mutations are a deletion eliminating three amino acids in the N-terminal region of SH3 domain and mutation of Ala 426 to Val. Analysis of the properties of chimeric src genes associating either half of PA101T with the complementary regions of PA101 or wild-type virus showed that the N-terminal moiety of PA101T src, which contains the deletion, confers wild-type transforming properties, whereas its C-terminal moiety, which contains single amino acid mutation, confers a partially temperature-sensitive phenotype. These results are consistent with other reports showing that mutations or deletions in this region of SH3 activate the transforming potential of c-src. They support the hypothesis that the N-terminal region of SH3 interacts with a cellular negative regulator of src activity.

Amino Acid Sequence↗
PubMed1977

Purification of DNA complementary to the env gene of avian sarcoma virus and analysis of relationships among the env genes of avian leukosis-sarcoma viruses.

The env gene of avian leukosis-sarcoma viruses encodes a glycoprotein that determines the host range and surface antigenicitiy of virions. We have purified radioactive DNA (cDNAgp) complementary to at least a portion of the env gene for viral subgroups A and C; complementary DNA was synthesized with purified virions of wild-type avian sarcoma virus, and RNA from a mutant with a deletion in env was used to select DNA specific to env by molecular hybridization. The genetic complexity of cDNAgp for subgroup A (ca. 2,000 nucleotides) was sufficient to represent the entire deletion and most or all of the env cistron. The deletions in env in two independently isolated strains of virus (Bryan and rdNY8SR) overlap, and cDNAgp represents nucleotide sequences common to both deletions. By contrast, we could detect no overlap between deletions in env and deletions in the adjacent viral gene src. Laboratory stocks of viral subgroups A, B, C, D and E do not contain detectable amounts of env deletions when tested by molecular hybridization; hence, segregation of deletions in env is a less frequent event that the segregation of deletions in the viral transforming gene src (Vogt, 1971). We found extensive homology among the nucleotide sequences encoding the env genes of virus strains indigenous to chickens (subgroups A, B, C, D, and E) although subgorups B, D and E appear to differ slightly from subgroups A and C at the env locus. By contrast, viruses obtained from pheasant cells (subgroups F and G) have env genes with little or no relationship to env genes of chikcen viruses. According to available data, viruses of subgroup F arose by recombination between an avarian sarcoma virus and viral genes in the genome of ring-necked pheasants, whereas subgroup G viruses may be entirely endogenous to golden pheasants.

Alpharetrovirus↗
PubMed1979

Avian acute leukemia viruses MC29 and MH2 share specific RNA sequences: evidence for a second class of transforming genes.

The genome of the defective avian tumor virus MH2 was identified as a RNA of 5.7 kilobases by its presence in different MH2-helper virus complexes and its absence from pure helper virus, by its unique fingerprint pattern of RNase T1-resistant (T1) oligonucleotides that differed from those of two helper virus RNAs, and by its structural analogy to the RNA of MC29, another avian acute leukemia virus. Two sets of sequences were distinguished in MH2 RNA: 66% hybridized with DNA complementary to helper-independent avian tumor viruses, termed group-specific, and 34% were specific. The percentage of specific sequences is considered a minimal estimate because the MH2 RNA used was about 30% contaminated by helper virus RNA. No sequences related to the transforming src gene of avian sarcoma viruses were found in MH2. MH2 shared three large T1 oligonucleotides with MC29, two of which could also be isolated from a RNase A- and T1-resistant hybrid formed between MH2 RNA and MC29 specific cDNA. These oligonucleotides belong to a group of six that define the specific segment of MC29 RNA described previously. The group-specific sequences of MH2 and MC29 RNA shared only the two smallest out of about 20 T1 oligonucleotides associated with MH2 RNA. It is concluded that the specific sequences of MH2 and MC29 are related, and it is proposed that they are necessary for, or identical with, the onc genes of these viruses. These sequences would define a related class of transforming genes in avian tumor viruses that differs from the src genes of avian sarcoma viruses.

Avian Leukosis Virus↗
PubMed1991

Conservation of structure and expression of the c-yes and fyn genes in lower vertebrates.

The src-gene family in mammals and birds consists of 9 closely related protein tyrosine kinases. We have cloned the c-yes and fyn homologues of the src-family from the teleost fish Xiphophorus helleri. Both genes show a high degree of sequence conservation and exhibit all structural motifs diagnostic for functional src-like protein tyrosine kinases. Sequence comparisons revealed three domains (exon 2, exons 3-6, exons 7-12) which evolve at different rates. Both genes exhibit an identical expression pattern, with preferential expression in neural tissues. No transcripts of c-yes were found in liver which is contrary to the situation in higher vertebrates. In malignant melanoma, elevated levels of c-yes and fyn were detected indicating a possible function during secondary steps of tumor progression for src-related tyrosine kinases.

Amino Acid Sequence↗
PubMed1983

Interaction between the Rous sarcoma virus transforming protein and two cellular phosphoproteins: analysis of the turnover and distribution of this complex.

The transforming protein of Rous sarcoma virus (RSV), pp60src, was previously shown to associate with two cellular proteins of Mr 90,000 and 50,000 in RSV-transformed chicken cells. In this report, we demonstrate that this interaction is specific for a discrete population of pp60src molecules. Newly synthesized pp60src was found to preferentially associate with pp90 and pp50 to form a short-lived complex. The half-life of this complex varied from 9 to 15 min in cells transformed by nondefective strains of RSV. This interaction between pp60src, pp50, and pp90 took place in a soluble fraction of the cell, and the complex-bound pp60src molecules were not phosphorylated on tyrosine. These results suggest that pp90 and pp50 may be involved in the processing of pp60src molecules before the association of pp60src with the plasma membrane. The kinetics of dissociation of this complex were shown to be altered in cells infected with viruses containing a temperature-sensitive defect in the src gene. When cells infected with these viruses were grown at the nonpermissive temperature, more than 90% of the pp60src molecules were associated with pp90 and pp50, and little or no dissociation was observed in a 3-h chase period. These results suggest that mutations in the src gene which affect the transforming activity of pp60src also affect the stability of the interaction of pp60src with pp90 and pp50.

Animals↗
PubMed1985

Modulation of fibronectin gene activity in chick embryo fibroblasts transformed by a temperature-sensitive strain (ts68) of Rous sarcoma virus.

Transcriptional regulation of the fibronectin gene is a major mechanism for lowering steady-state levels of fibronectin mRNA in chick embryo fibroblasts (CEF) transformed by Rous sarcoma virus (RSV) (1). In the present study, we have measured the change of transcriptional activity of the fibronectin gene in CEF transformed by a temperature-sensitive strain of RSV (ts68). Ts68-CEF maintained at either 35 degrees C or 41 degrees C were shifted to 41 degrees C or 35 degrees C, respectively, at 5-hour intervals, and isolated nuclei were used in runoff transcription assays. Nuclear RNA labeled with [alpha-32P]UTP was hybridized to DNA fragments encoding the src gene, the beta-actin gene and the fibronectin gene. In shift-up (35 degrees C----41 degrees C) and shift-down (41 degrees C----35 degrees C) experiments, src gene and beta-actin gene activities in ts68-CEF nuclei remained relatively unchanged. In ts68-CEF shifted to the nonpermissive temperature (41 degrees C), a lag time of at least 5 hours was followed by a 4- to 5-fold increase in fibronectin specific RNA 15 hours after the shift. When cells were shifted to the permissive temperature (35 degrees C), a 4- to 5-fold decrease in fibronectin RNA was apparent within 5 hours of the temperature shift and a 17- to 18-fold decrease was observed 15 hours after the shift. The relatively slow rates of changes of fibronectin gene activity in shift-up experiments suggest that the effect of p60src on fibronectin gene activity is indirect.

Animals↗
PubMed1992

Osteoclasts express high levels of pp60c-src in association with intracellular membranes.

Deletion of the c-src gene in transgenic mice by homologous recombination leads to osteopetrosis, a skeletal defect characterized by markedly deficient bone resorption (Soriano, P., C. Montgomery, R. Geske, and A. Bradley. 1991. Cell. 64:693-702), demonstrating a critical functional role of pp60c-src in osteoclast activity. Since decreased bone resorption could result from a defect either within the osteoclast or within other cells present in its environment, indirectly affecting osteoclast functions, we determined which cell(s) in bone expressed high levels of pp60c-src Measuring pp60c-src protein and kinase activities in osteoclasts and immunolocalizing pp60c-src in bone, we find that expression of pp60c-src is nearly as high in osteoclasts as in brain and platelets. In contrast, other bone cells contain only very low levels of the protein. In addition, expression of the c-src gene product increases when bone marrow cells are induced to express an osteoclast-like phenotype by 1,25-dihydroxy-vitamin D3, further suggesting that high expression of pp60c-src is part of the osteoclast phenotype. Three other src-like kinases, c-fyn, c-yes, and c-lyn, are also expressed in osteoclasts at ratios to pp60c-src similar to what is found in platelets. These src-related proteins do not, however, compensate for the absence of pp60c-src in the src- mice, thereby suggesting that pp60c-src may have a specific function in osteoclasts. Although further work is necessary to elucidate what the critical role of pp60c-src in osteoclasts is, our observation that the protein is associated mostly with the membranes of intracellular organelles suggests the possibility that this role might be at least in part related to the targeting or fusion of membrane vesicles.

Animals↗
PubMed1983

Characterization of exogenous proviral sequences in hamster tumor cell lines transformed by Rous sarcoma virus rescued from XC cells.

Alterations in viral structural genes have been studied in five cell lines derived from Syrian hamster tumors which had been induced by the virus rescued from XC cells by transfection. Two cell lines, H-18 and H-20, have all the viral structural genes expressed, but a new EcoRI recognition site appeared in the region of the pol gene sequence. Provirus present in H-12 lacks the 3' part of the gag gene sequences as well as the pol gene, therefore, it gives rise to an anomalous 1.8 Md EcoRI fragment. This line also does not synthesize viral RNA of genomic size, and none of the subgenomic RNAs found hybridized with the DNApol probe. The H-19 cell line harbors only the src gene and LTR sequences, the U3 part of which seems incomplete or different from that of PR-RSV. The cryptic proviral structure in H-19 is transcribed into src mRNA. The degree of transcription of the src gene is about 25 viral RNA equivalents per cell. The H-9 cells harbor the complete provirus and, in addition, proviral structures having the deletion in gag-pol genes. The possible ways of development of provirus alterations and the role of cryptic proviral sequences in oncogenesis are discussed.

Animals↗
PubMed2001

SRC transcriptional activation in a subset of human colon cancer cell lines.

Human SRC encodes the non-receptor tyrosine kinase pp60(c-Src), which is activated in many human colon cancer cell lines (HCCLs) and tumors. We found that both c-Src protein and mRNA levels were elevated in a subset of HCCLs. Increased c-Src mRNA and protein levels correlated strongly with increased c-Src kinase activity. Nuclear run-on analysis and c-Src mRNA half-life determination demonstrated increased mRNA levels were due to increased transcription of the SRC gene. We also observed decreased c-Src mRNA stability in cell lines that displayed SRC transcriptional activation. Our findings provide the first evidence that SRC transcriptional activation is an important determinant of c-Src expression and activity in HCCLs.

Colonic Neoplasms↗
PubMed1983

Antibodies to a defined region of pp60src neutralize the tyrosine-specific kinase activity.

Site-specific antibodies to pp60src, the transforming protein of Rous sarcoma virus (RSV), have been prepared by immunizing rabbits with a chemically synthesized pentadecapeptide corresponding to residues 498-512 (Cys-Trp-Arg-Lys-Asp-Pro-Glu-Glu-Arg-Pro-Thr-Phe-Lys-Tyr-Leu) as deduced from the nucleotide sequence of the Prague C src gene. Antibodies specific for the synthetic peptide were purified from immune sera by affinity chromatography on peptide-bound Sepharose and characterized by a number of immunocytochemical techniques. Immunoprecipitation and Western blot analyses of normal and RSV-transformed cell lines revealed that this peptide antibody identified the authentic viral src gene product. This finding was further supported by indirect immunofluorescence on RSV-transformed rat kidney cells. The anti-peptide antibodies produced dramatic intracellular staining patterns characteristic of the src protein. Although able to immunoprecipitate pp60src, in vitro kinase reactions indicated that, unlike sera from RSV-induced tumor-bearing rabbits, the peptide antibody did not serve as a phosphate acceptor in the immunocomplex. Moreover, immunoprecipitates of pp60src prepared from this site-specific immune reagent were unable to phosphorylate exogenously added casein or the synthetic peptide substrate, Arg-Arg-Leu-Ile-Glu-Asp-Ala-Glu-Tyr-Ala-Ala-Arg-Gly. In contrast, pp60src-containing immunoprecipitates made from an anti-peptide serum specific for the COOH-terminal six amino acids (residues 521-526), a region only eight amino acids removed, readily phosphorylated both substrates. This evidence indicates that an antibody directed against residues 498-512 neutralizes the kinase activity of pp60src and suggests that this region may be functionally necessary for the tyrosine-specific kinase activity of this transforming protein.

Animals↗
PubMed1985

Differential translation of virogenic and oncogenic sequences in malignant lymphoproliferative diseases and transfection of coding DNAs into NIH 3T3 cells.

The expression of oncoviral p30 polypeptides and onc gene-specific proteins has been examined in different human lymphoid malignancies. The distribution of antigen(s) related to the p30 of BaEV lacked any specificity. Antigen(s) related to the main core polypeptide of GaLV could be detected mainly in B- and O-cell malignancies. The myc-encoded protein was translated at higher levels in malignant than in normal lymphoid cells. An active src gene was identified in three acute lymphoid leukaemias and in one non-Hodgkin lymphoma of T-cell origin. Human DNAs coding oncoviral antigens or onc gene-specific proteins could be transfected into NIH 3T3 cells. These data suggest that the synergistic effect of the myc and src genes would operate in malignant transformation of some progenitors of T-cell lineage.

Animals↗
PubMed1980

Interaction between cellular and viral genes in the expression of the RSV-induced transformation-specific cell-surface antigen VCSA.

Transformation of BHK hamster fibroblasts by an env- strain of Rous sarcoma virus (RSV) leads to the appearance at the cell surface of a virus-induced nonvirion antigen (VCSA), specific for transformation, whose expression is controlled by the transforming src gene. Previous work has shown that a rabbit anti-VCSA serum lyses specifically, in the presence of complement, 51Cr-labelled RSV-transformed cells from different animal species. Now, by competition experiments with a panel of different unlabelled cells we show that the VCSA expressed on RSV-transformed hamster fibroblasts is a complex of at least three distinct antigenic specificities: (1) one expressed on all RSV-transformed fibroblasts, regardless their species and the subgroup or strain of the transforming virus; (2) one cross-reacting with a cell-surface antigen (CSA) expressed at various degrees on untransformed avian fibroblasts, but not on mammalian fibroblasts; (3) one species-specific, present only on RSV-transformed hamster fibroblasts. It is concluded that VCSA is a complex of several antigenic determinants, and that some of these differ in different cells transformed by RSV. This observation indicates that VCSA expression at the cell surface is likely to be the result of the interaction between the viral src gene product pp60src with host cell gene(s) or gene product(s), rather than the simple expression of this molecule at the cell surface.

Animals↗
PubMed1983

Isolation and partial characterization of a monoclonal antibody to the Rous sarcoma virus transforming protein pp60src.

Transformation of cells by Rous sarcoma virus is mediated by the product of the viral src gene, pp60src. A hybridoma cell line producing an immunoglobulin G3 antibody to pp60src was isolated after lymph node cells from immune mice were fused with mouse myeloma cells (P3-NS1-1). Mice were immunized with p60src purified from Escherichia coli cells expressing the src gene product. The monoclonal antibody immunoprecipitated pp60src from Rous sarcoma virus-transformed cells and recognized an antigenic determinant located in the amino-terminal third of the pp60src protein.

Animals↗
PubMed1985

Two independent mutations are required for temperature-sensitive cell transformation by a Rous sarcoma virus temperature-sensitive mutant.

We molecularly cloned the src coding region of tsNY68, a mutant of Rous sarcoma virus temperature sensitive (ts) for transformation, and constructed a series of ts wild-type recombinant src genes. DNA containing the hybrid genes was transfected into chicken cells together with viral vector DNA and helper viral DNA, and infectious transforming viruses were recovered. Characterization of these recombinant viruses indicated that at least two mutations are present in the 3' half of the mutant src gene, both of which are required for ts. Nucleotide sequence analysis revealed three differences in the deduced amino acid sequence compared with the parental virus. Two of these changes, a deletion of amino acids 352 to 354 and an amino acid substitution at position 461, are responsible for the ts phenotype.

Animals↗