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A V Lauver

Publications and source records attributed to A V Lauver.

6 recordsLinked to original sources
PubMed1982

Transforming genes in human tumors.

DNAs isolated from a variety of human tumor cell lines as well as from naturally occurring human carcinomas and sarcomas were shown to induce morphologic transformation upon transfection into NIH/3T3 cells. All tested transformants contained human DNA sequences, some of which specifically cosegregated with the malignant phenotype in additional cycles of transfection. Southern blot analysis of second cycle transformants derived from T24 human bladder carcinoma cells showed the presence of a single 15 kbp EcoRI fragment of human DNA. These sequences were molecularly cloned utilizing lambda Charon 9A as the cloning vector. The resulting recombinant DNA molecule, designated lambda T24-15A, was shown to contain an internal 6.6 kbp Bam HI fragment of human DNA that transformed NIH/3T3 fibroblasts with a specific activity of 5 X 10(4) focus forming units per picomole. These results indicate that we have molecularly cloned an oncogene present in T24 bladder carcinoma cells. Comparison of molecular clones containing the T24 oncogene and its normal homologue did not reveal biochemical differences that helped to explain the malignant properties of this oncogene. Finally, we report preliminary results indicating that the T24 bladder carcinoma oncogene is highly related to the transforming gene of BALB-MSV, an acute transforming retrovirus.

Animals↗
PubMed1982

Oncogenes in human tumor cell lines: molecular cloning of a transforming gene from human bladder carcinoma cells.

The presence of dominant transforming genes in human tumor cell lines has been investigated. High molecular weight DNAs isolated from cell lines established from carcinomas and sarcomas of various organs as well as from a glioblastoma and two melanomas were utilized to transfect NIH/3T3 mouse fibroblasts. The DNAs of T24 and A2182, two cell lines derived from a bladder and a lung carcinoma, respectively, and of HT-1080, a cell line established from a fibrosarcoma, were able to transform recipient NIH/3T3 cells. First-cycle transformants exhibited anchorage-independent growth and were tumorigenic in athymic and immunocompetent mice. Moreover, they contained human DNA sequences and were able to transmit their malignant phenotype in additional cycles of transfection. Southern blot analysis of T24-derived transformants showed that a single fragment of human DNA specifically cosegregated with the malignant phenotype, suggesting that it contained the T24 oncogene. Therefore, these human sequences were molecularly cloned with lambda Charon 9A as the cloning vector. The resulting recombinant DNA molecule, designated lambda T24-15A, was shown to contain a 15-kilobase-pair EcoRI insert of human cellular DNA. lambda T24-15A DNA (either intact or EcoRI digested) transformed NIH/3T3 fibroblasts with a specific activity of 20,000 focus-forming units per pmol of cloned DNA. Our results indicate that we have molecularly cloned a biologically active oncogene present in T24 human bladder carcinoma cells.

Carcinoma↗
PubMed1981

Gene products of McDonough feline sarcoma virus have an in vitro-associated protein kinase that phosphorylates tyrosine residues: lack of detection of this enzymatic activity in vivo.

The primary translational product of the McDonough (SM) strain of feline sarcoma virus (FeSV) is a 180,000-dalton molecule, SM P180, that contains the p15-p12-p30 region of the FeLV gag gene-coded precursor protein and a sarcoma virus-specific polypeptide. In addition, cells transformed by SM-FeSV express a 120,000-dalton molecule, SM P120, that is highly related to the non-helper virus domain of SM P180. Both SM-FeSV gene products were found to be intimately associated with the membrane fraction of SM-FeSV-transformed cells. Immunoprecipitates containing SM P180 and SM P120 exhibited a protein kinase activity capable of phosphorylating tyrosine residues of both viral gene products but not immune immunoglobulin G molecules. By independently immunoprecipitating each of the two SM-FeSV proteins we found that most of the tyrosine-specific phosphorylating activity was associated with the SM P120 molecule. In vivo analysis of 32P-labeled SM P180 and SM P120 revealed their phosphoprotein nature; however, both molecules exhibited low levels of phosphorylation and did not contain phosphotyrosine residues. Finally, we did not detect any significant elevation in the levels of phosphotyrosine in the protein fraction of SM-FeSV transformants. Thus, if SM-FeSV were to induce malignant transformation by a mechanism involving phosphorylation of tyrosine residues, the viral gene products must interact with a small subset of cellular proteins that do not represent a significant fraction of the total cellular protein content.

Animals↗
PubMed1980

Biochemical and immunological characterization of polyproteins coded for by the McDonough, Gardner-Arnstein, and Snyder-Theilen strains of feline sarcoma virus.

The McDonough (SM), Gardner-Arnstein (GA), and Snyder-Theilen (ST) strains of feline sarcoma virus (FeSV) code for high-molecular-weight polyproteins that contain varying amounts of the amino-terminal region of the FeLV gag gene-coded precursor protein and a polypeptide(s) of an as yet undetermined nature. The SM-FeSV primary translational product is a 180,000-dalton polyprotein which is immediately processed into a highly unstable 60,000-dalton molecule containing the p15-p12-p30 fragment of the FeLV gag gene-coded precursor protein and a 120,000-dalton FeSV-specific polypeptide. The GA- and ST-FeSV genomes code for polyproteins of 95,000 and 85,000 daltons, respectively, which in addition to the amino-terminal moiety (p15-12 and a portion of p30) of the FeLV gag gene-coded precursor protein also contain FeSV-specific polypeptides. However, the GA- and ST-FeSV polyproteins appear to be relatively stable molecules (half-lives of around 16 h) and are not significantly processed into smaller polypeptides. Immunological and biochemical analysis of each of the above FeSV translational products revealed that the sarcoma-specific regions of the GA- and ST-FeSV polyproteins are antigenically cross-reactive and exhibit common methionine-containing peptides. These findings favor the concept that these sarcoma-specific polypeptides are coded for by the similar subsets of cellular sequences incorporated into the GA- and ST-FeSV genomes during the generation of these transforming agents.

Animals↗