PubMed Health⌕ Search

Biomedical subjects

S R Tronick

Publications and source records attributed to S R Tronick.

At least 73 records · Page 4Linked to original sources
PubMed1983

Regional chromosomal localization of N-ras, K-ras-1, K-ras-2 and myb oncogenes in human cells.

The identification of transforming genes in human tumor cells has been made possible by DNA mediated gene transfer techniques. To date, it has been possible to show that most of these transforming genes are activated cellular analogues of the ras oncogene family. To better understand the relationship between these oncogenes and other human genes, we have determined their chromosomal localization by analyzing human rodent somatic cell hybrids with molecularly cloned human proto-oncogene probes. It was possible to assign N-ras to chromosome 1 and regionally localize c-K-ras-1 and c-K-ras-2 to human chromosomes 6pter-q13 and 12q, respectively. These results along with previous studies demonstrate the highly dispersed nature of ras genes in the human genome. Previous reports indicated that the c-myb gene also resides on chromosome 6. It has been possible to sublocalize c-myb to the long arm of chromosome 6 (q15-q21). The non-random aberrations in chromosomes 1, 6 and 12 that occur in certain human tumors suggest possible etiologic involvement of ras and/or myb oncogenes in such tumors.

Animals↗
PubMed1983

Transforming genes of human hematopoietic tumors: frequent detection of ras-related oncogenes whose activation appears to be independent of tumor phenotype.

We surveyed 22 human hematopoietic tumors and tumor cell lines for sequences capable of transforming NIH 3T3 cells by DNA transfection. A primary human acute myelogenous leukemia, a chronic myelogenous leukemia cell line, and cell lines derived from three independent acute lymphocytic leukemias demonstrated oncogenes capable of conferring the transformed phenotype to NIH 3T3 cells through serial cycles of transfection. One of three transforming genes associated with acute lymphocytic leukemia cells (classified as thymocyte developmental stage II) was identified as the activated cellular homologue of the Kirsten murine sarcoma virus onc gene, kis, a member of the ras family of onc genes. A transforming gene, which was demonstrated to be common to several human myeloid and lymphoid tumor cells, was shown to be a distantly related member of the ras gene family. Thus, the NIH 3T3 transfection assay commonly detects related oncogenes in human hematopoietic tumor cells. Moreover, the activation of these oncogenes appears to be independent of the specific stage of cell differentiation or tumor phenotype.

Alleles↗
PubMed1983

Structural organization and expression of human DNA sequences related to the transforming gene of avian myeloblastosis virus.

Bacteriophage libraries of human DNA were screened for sequences homologous to the transforming gene (v-myb) of avian myeloblastosis virus. The three overlapping clones isolated were shown to contain a total of 1.0 kilobase pair (kbp) of sequence related to v-myb distributed over 6.2 kbp. Restriction enzyme mapping and heteroduplex analysis revealed the presence of five myb-related domains interrupted by four stretches of non-homology. To study the extent of human DNA coding sequences that constitute the myb gene homologue, c-myb (human), probes spanning about 30 kbp were prepared from the clones and used to study transcription in a human hematopoietic cell line (MOLT-4). Each of the probes hybridized a 4.5-kilobase transcript, which suggests that either the c-myb (human) gene encompasses 30 kbp or it contains two or more transcription units that each give rise to a mRNA of 4.5 kilobases.

Avian Leukosis Virus↗
PubMed1983

Molecular cloning of the unintegrated squirrel monkey retrovirus genome: organization and distribution of related sequences in primate DNAs.

The closed circular form of the endogenous squirrel monkey type D retrovirus (SMRV) was molecularly cloned in a bacteriophage vector. The restriction map of the biologically active clone was determined and found to be identical to that of the parental SMRV linear DNA except for the deletion of one long terminal repeat. Restriction enzyme analysis and Southern blotting indicated that the SMRV long terminal repeat was approximately 300 base pairs long. The SMRV restriction map was oriented to the viral RNA by using a gene-specific probe from baboon endogenous virus. Restriction enzyme digests of a variety of vertebrate DNAs were analyzed for DNA sequence homology with SMRV by using the cloned SMRV genome as a probe. Consistent with earlier studies, multiple copies of SMRV were detected in squirrel monkey DNA. Related fragments were also detected in the DNAs from other primate species, including humans.

Animals↗
PubMed1983

Molecular cloning of integrated Gardner-Rasheed feline sarcoma virus: genetic structure of its cell-derived sequence differs from that of other tyrosine kinase-coding onc genes.

Gardner-Rasheed feline sarcoma virus (GR-FeSV) is an acute transforming retrovirus which encodes a gag-onc polyprotein possessing an associated tyrosine kinase activity. The integrated form of this virus, isolated in the Charon 21A strain of bacteriophage lambda, demonstrated an ability to transform NIH/3T3 cells at high efficiency upon transfection. Foci induced by GR-FeSV DNA contained rescuable sarcoma virus and expressed GR-P70, the major GR-FeSV translational product. The localization of long-terminal repeats within the DNA clone made it possible to establish the length of the GR-FeSV provirus as 4.6 kilobase pairs. The analysis of heteroduplexes formed between lambda feline leukemia virus (FeLV) and lambda GR-FeSV DNAs revealed the presence of a 1,700-base-pair FeLV unrelated segment, designated v-fgr, within the GR-FeSV genome. The size of this region was sufficient to encode a protein of approximately 68,000 daltons and was localized immediately downstream of the FeLV gag gene coding sequences present in GR-FeSV. Thus, it is likely that this 1.7-kilobase-pair stretch encodes the onc moiety of GR-P70. Utilizing probes representing v-fgr, we detected homologous sequences in the DNAs of diverse vertebrate species, implying that v-fgr originated from a well-conserved cellular gene. The number of cellular DNA fragments hybridized by v-fgr-derived probes indicated either that proto-fgr is distributed over a very large region of cellular DNA or represents a family of related genes. By molecular hybridization, v-fgr was not directly related to the onc genes of other known retroviruses having associated tyrosine kinase activity.

Animals↗
PubMed1982

Localization of the normal allele of T24 human bladder carcinoma oncogene to chromosome 11.

The development of DNA-mediated gene transfer techniques has made it possible to identify transforming genes present in certain human tumour cells. Such genes have been shown to induce morphological transformation when used to transfect suitable assay cells. Recently a transforming gene has been isolated by molecular cloning techniques from the T24 (ref. 11) and EJ (ref. 12) human bladder carcinoma cell lines. This bladder carcinoma oncogene has been shown to be of human origin, less than six kilobase pairs (kbp) in size, and closely related to the onc genes (v-bas and v-ras) of BALB and Harvey murine sarcoma viruses. These transforming retroviruses arose in nature by transduction of cellular genes from mouse and rat cells, respectively. To understand better the relationship of the T24 oncogene with other human cellular genes, we have determined the chromosomal location of its normal allele within the human genome. We show here that it is carried on chromosome 11 in normal cells.

Alleles↗
PubMed1982

T24 human bladder carcinoma oncogene is an activated form of the normal human homologue of BALB- and Harvey-MSV transforming genes.

A transforming gene isolated from T24 human bladder carcinoma cells is closely related to the BALB murine sarcoma virus (MSV) onc gene (v-bas). This transforming gene is localized to a 4.6 kilobase pair (kbp) region and is expressed as a 1.2-kbp polyadenylated transcript, which contains v-bas related sequences. Moreover, antisera known to detect the immunologically related onc gene products of BALB- and Harvey-MSVs recognized elevated levels of a related protein in T24 cells. The normal human homologue of v-bas was found to be indistinguishable from the T24 oncogene by heteroduplex and restriction enzyme analysis. These results imply that rather subtle genetic alterations have led to the activation of the normal human homologue of v-bas as a human transforming gene.

Animals↗
PubMed1982

Nucleotide sequence of the transforming gene of simian sarcoma virus.

The sequence of the transforming region of simian sarcoma virus (SSV) has been determined by using molecularly cloned viral DNA. This region encompassed the 1.0-kilobase pair woolly monkey cell-derived insertion sequence, v-sis, and flanking simian sarcoma-associated viral (SSAV) sequences. A 675-nucleotide-long open reading frame commenced 19 nucleotides within the SSAV sequences to the left of the v-sis helper viral junction and terminated within v-sis itself. Possible promoter and acceptor splice signals were detected in helper viral sequences upstream from this open reading frame, and potential polyadenylylation sites were identified downstream both within v-sis and in helper viral sequences beyond v-sis. The recombinational event that led to the generation of SSV occurred in the middle of two functional codons, indicating that SSAV provided the regulatory elements for transcription as well as the initiation codon for translation of SSV cell-derived transforming sequences.

Cell Transformation, Viral↗
PubMed1982

Molecular cloning and chromosomal mapping of a human locus related to the transforming gene of Moloney murine sarcoma virus.

Human DNA was analyzed for the presence of sequences homologous to the transforming gene (v-mos) of Moloney murine sarcoma virus. A single 2.5-kilobase pair (kbp) EcoRI-generated fragment of human DNA was identified by using cloned v-mos as probe. This DNA was molecularly cloned in a bacteriophage vector. By heteroduplex and restriction enzyme analyses, this human DNA fragment, designated c-mos (human), contained a 0.65-kbp region of continuous homology with v-mos and was present as a single copy in human DNA. By testing for the presence of c-mos (human) in somatic cell hybrids possessing various numbers of human chromosomes, as well as in subclones of such hybrids, it was possible to assign c-mos (human) to human chromosome 8.

Base Sequence↗
PubMed1982

Expression of cellular homologues of retroviral onc genes in human hematopoietic cells.

Total cellular poly(A)-enriched RNA from a variety of fresh human leukemic blood cells and hematopoietic cell lines was analyzed for homology with molecularly cloned DNA probes containing the onc sequence of Abelson murine leukemia virus (Ab-MuLV), Harvey murine sarcoma virus (Ha-MuSV), simian sarcoma virus (SSV), and avian myelocytomatosis virus strain MC29. Results with the fresh blood cells paralleled those obtained with the cell lines. With Ab-MuLV and Ha-MuSV, multiple RNA bands were visualized in all cell types examined without significant variation in the relative intensities of the bands. When SSV was used as the probe, expression of related onc sequences was absent in all of the hematopoietic cell types examined except for one neoplastic T-cell line (HUT 102), which produces the human T-cell leukemia (lymphoma) retrovirus HTLV. In this cell line, a single band (4.2 kilobases) was observed. With MC29 as the probe, a single band of 2.7 kilobases was visualized in all cell types examined with only a 10 to 2-fold variation in intensity of hybridization. An exception was the promyelocytic cell line, HL60, which expressed approximately 10-fold more MC29-related onc sequences. With induction of differentiation of HL60 with either dimethyl sulfoxide or retinoic acid, a marked diminution in the amount of the MC29-related, but not the Ab-MuLV-related, onc message was observed.

B-Lymphocytes↗
PubMed1981

Generation of BALB-MuSV and Ha-MuSC by type C virus transduction of homologous transforming genes from different species.

The nature of the cell-derived (bas) sequences of BALB-MuSV, a spontaneous mouse sarcoma virus isolate, was determined. Molecularly cloned bas sequences demonstrated no detectable homology with the onc genes of other mouse transforming viruses, but exhibited a high degree of sequence homology with the ras gene of the rat-derived Harvey murine sarcoma virus (Ha-MuSV) genome. The Ha-MuSV cell-derived sequence (ras) shared a colinear 750 bp region of homology with bas. Moreover, BALB-MuSV transformation was associated with the expression of high levels of a 21,000 dalton protein, immunologically related to the ras gene products, p21. Thus bas and ras represent retroviral transforming gene homologs that were independently transduced by mouse type C viruses from the genomes of different species.

Abelson murine leukemia virus↗
PubMed1981

Structural organization and biological activity of molecular clones of the integrated genome of a BALB/c mouse sarcoma virus.

BALB/c mouse sarcoma virus (BALB-MSV) is a spontaneously occurring transforming retrovirus of mouse origin. The integrated form of the viral genome was cloned from the DNA of a BALB-MSV-transformed nonproducer NRK cell line in the Charon 9 strain of bacteriophage lambda. In transfection assays, the 19-kilobase-pair (kbp) recombinant DNA clone transformed NIH/3T3 mouse cells with an efficiency of 3 X 10(4) focus-forming units per pmol. Such transformants possessed typical BALB-MSV morphology and released BALB-MSV after helper virus superinfection. A 6.8-kbp DNA segment within the 19-kbp DNA possessed restriction enzyme sites identical to those of the linear BALB-MSV genome. Long terminal repeats of approximately 0.6 kbp were localized at either end of the viral genome by the presence of a repeated constellation of restriction sites and by hybridization of segments containing these sites with nick-translated Moloney murine leukemia virus long terminal repeat DNA. A continuous segment of at least 0.6 and no more than 0.9 kbp of helper virus-unrelated sequences was localized toward the 3' end of the viral genome in relation to viral RNA. A probe composed of these sequences detected six EcoRI-generated DNA bands in normal mouse cell DNA as well as a smaller number of bands in rat and human DNAs. These studies demonstrate that BALB-MSV, like previously characterized avian and mammalian transforming retroviruses, arose by recombination of a type C helper virus with a well-conserved cellular gene.

Animals↗
PubMed1980

Nucleotide sequence analysis of the transforming region and large terminal redundancies of Moloney murine sarcoma virus.

The sequence of the transforming region of the Moloney murine sarcoma virus genome has been determined by using molecularly cloned viral DNA. This region, 3.6 to 5.8 kilobase pairs from the left end of the molecule, contains the entire cellular insertion (src) sequence as well as helper viral sequences including the large terminal repeat (LTR). On the viral RNA strand, a long (1224 bases) open reading frame commenced to the left of the src-helper virus junction and terminated at a point 58 nucleotides into helper viral sequences to the right of src. Possible promoter and acceptor splice signals were detected in helper viral sequences upstream from this open reading frame. On the antiviral RNA strand, several promoter-like sequences, including one within the src region itself, were identified. However, no open reading frame downstream from these promoters was detected in the antiviral RNA strand. The LTR was found to contain promoter-like sequences as well as LTR was found to contain promoter-like sequences as well as mRNA capping and polyadenylylation signals. In addition, it possessed an 11-base inverted terminal repeat at each end. Thus, the structure of the Moloney murine sarcoma virus genome with an LTR at each end resembles that of prokaryotic transposable elements.

Bacteriophage lambda↗
PubMed1980

Immunological relationships of an endogenous guinea pig retrovirus with prototype mammalian type B and type D retroviruses.

A retrovirus endogenous to guinea pig cells was earlier shown to be morphologically similar to type B and type D prototype retroviruses. Molecular hybridization techniques were used to show that guinea pig virus nucleotide sequences are endogenous to both domestic (Cavia porcellus) and indigenous (Cavia aperea) guinea pigs, but cannot be detected in the DNA of either other hystricomorph rodents or other mammals tested. Using radioimmunological techniques designed to detect interspecies relationships, the major internal polypeptide of guinea pig virus (p26) was shown to share three different sets of interspecies antigenic determinants with squirrel monkey retrovirus, viper retrovirus, and mouse mammary tumor virus. Thus, guinea pig virus appears to provide an evolutionary link between type B and D retroviruses.

Animals↗
PubMed1979

Evolutionary relatedness of viper and primate endogenous retroviruses.

A retrovirus previously isolated from a tumored Russell's viper is shown by molecular hybridization to be an endogenous virus of this reptilian species. Radio-immunologic techniques revealed that the viper retrovirus is immunologically and, hence, evolutionarily related to endogenous type D retorviruses of Old World primates. These findings extend the number of vertebrate classes possessing endogenous retroviruses and suggest that type D retroviruses may even be more widely distributed in nature than type C retroviruses.

Animals↗
PubMed1979

Molecular cloning of Moloney murine sarcoma virus: arrangement of virus-related sequences within the normal mouse genome.

The unintegrated circular DNA form of Moloney murine sarcoma virus (MSV) has been cloned in bacteriophage lambda. Discrete deletions in the viral genome were shown to occur during propagation of recombinant phage in Escherichia coli. Heteroduplex and restriction enzyme analyses indicated the deletion of tandemly repeated sequences within certain of the cloned MSV DNA inserts. Cloned MSV DNA was used to prepare a probe composed of its acquired cellular (src) sequences, shown previously to be necessary for MSV transformation. Analysis of EcoRI digests of normal mouse cellular DNA revealed the presence of a single 14-kilobase-pair fragment containing these sequences which lacked contiguity with endogenous type C helper viral information of the same cells. Thus, the sarcoma virus-specific sequences of MSV are represented within the normal mouse genome in a manner analogous to that of a cellular gene.

Animals↗