476
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Park M, Dean M, Kaul K, Braun MJ, Gonda MA, Vande Woude G. Sequence of MET protooncogene cDNA has features characteristic of the tyrosine kinase family of growth-factor receptors. Proc Natl Acad Sci U S A 1987; 84:6379-83. [PMID: 2819873 PMCID: PMC299079 DOI: 10.1073/pnas.84.18.6379] [Citation(s) in RCA: 444] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We isolated overlapping cDNA clones corresponding to the major MET protooncogene transcript. The cDNA nucleotide sequence contained an open reading frame of 1408 amino acids with features characteristic of the tyrosine kinase family of growth factor receptors. These features include a putative 24-amino acid signal peptide and a candidate, hybrophobic, membrane-spanning segment of 23 amino acids, which defines an extracellular domain of 926 amino acids that could serve as a ligand-binding domain. A putative intracellular domain 435 amino acids long shows high homology with the SRC family of tyrosine kinases and within the kinase domain is most homologous with the human insulin receptor (44%) and v-abl (41%). Despite these similarities, however, we found no apparent sequence homology to other growth factor receptors in the putative ligand-binding domain. We conclude from these results that the MET protooncogene is a cell-surface receptor for an as-yet-unknown ligand.
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477
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478
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479
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Dean M, Cleveland JL, Rapp UR, Ihle JN. Role of myc in the abrogation of IL3 dependence of myeloid FDC-P1 cells. ONCOGENE RESEARCH 1987; 1:279-96. [PMID: 2453016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We have constructed a recombinant retrovirus containing the murine c-myc and the neo gene and introduced the virus into the interleukin-3 (IL3) dependent myeloid cell line FDC-P1. Unregulated expression of the introduced c-myc gene is associated with both an increased viability and constitutive ornithine decarboxylase mRNA levels in FDC-P1 cells grown in the absence of IL3. FDC-P1 cells infected with the c-myc virus gave rise to IL3 independent lines. Three out of four independent lines have an activated endogenous c-myc or N-myc gene. We have also shown that c-myc mRNA levels are tightly regulated by IL3 in FDC-P1 cells. Taken together these results indicate that myc plays a critical role in the signal transduction pathway of IL3. Furthermore, activation of the N-myc gene may be one mechanism for myeloid cells to progress to complete IL3 independence.
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480
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Abstract
We determined the nucleotide sequence of the rearranged trp-met genomic locus and the corresponding portions of the unrearranged tpr and met genomic fragments. The breakpoints occur at one end of a stretch of 21 A residues that follow an Alu repetitive sequence in the tpr locus and within a group of 3 A residues in the met proto-oncogene locus. We conclude that the fusion between the tpr locus on chromosome 1 and the met locus on chromosome 7 resulted from a recombination event.
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481
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Dean M, Park M, Kaul K, Blair D, Vande Woude GF. Activation of the met proto-oncogene in a human cell line. HAEMATOLOGY AND BLOOD TRANSFUSION 1987; 31:464-8. [PMID: 3327781 DOI: 10.1007/978-3-642-72624-8_99] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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482
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White R, Leppert M, O'Connell P, Nakamura Y, Woodward S, Hoff M, Herbst J, Dean M, Vande Woude G, Lathrop GM. Further linkage data on cystic fibrosis: the Utah Study. Am J Hum Genet 1986; 39:694-8. [PMID: 2879438 PMCID: PMC1684126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We reported earlier complete linkage between cystic fibrosis and an RFLP of the met proto-oncogene revealed by the probe pmetH. Another clone, pmetD, detects another polymorphism with the TaqI restriction enzyme. Further linkage studies, now involving 22 families, have confirmed the tight linkage of cystic fibrosis to the MET and D7S8 loci. Significant allelic association was found between CF and allelic series defined by the pmetH probe.
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483
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Ran W, Dean M, Levine RA, Henkle C, Campisi J. Induction of c-fos and c-myc mRNA by epidermal growth factor or calcium ionophore is cAMP dependent. Proc Natl Acad Sci U S A 1986; 83:8216-20. [PMID: 2430281 PMCID: PMC386898 DOI: 10.1073/pnas.83.21.8216] [Citation(s) in RCA: 115] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Phorbol esters activate protein kinase C and induce expression of the c-fos and c-myc protooncogenes in density-arrested BALB/c 3T3 (A31) cells; in contrast, epidermal growth factor (EGF) does not activate protein kinase C and is a poor inducer of c-fos and c-myc in these confluent cells. We show that, when A31 cells were subconfluent and made quiescent by serum deprivation, the phorbol ester phorbol 12-myristate 13-acetate induced c-fos and c-myc mRNA poorly, whereas EGF was a better inducer. Another platelet-derived growth factor-inducible gene, JE, did not show this differential regulation by phorbol 12-myristate 13-acetate and EGF. The ability of EGF to induce protooncogene mRNA was associated with elevated levels of intracellular cAMP. First, serum-deprived cells maintained cAMP at about 2-fold higher level than density-arrested cells. Second, induction was greatly enhanced by cholera toxin and 3-isobutyl-1-methylxanthine, which increased intracellular cAMP 3- to 10-fold. The calcium ionophore A23187 mimicked EGF in that it elevated c-fos and c-myc mRNA when administered with cholera toxin and isobutylmethylxanthine. Neither cholera toxin and isobutyl-methylxanthine nor A23187 appreciably induced these mRNAs when used alone. Our results suggest that c-fos and c-myc expression can be regulated by an EGF-directed pathway that utilizes calcium and cAMP as cooperating cytoplasmic messengers.
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484
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Adinolfi M, McColl I, Chase D, Fensom AH, Welsh K, Brown S, Marsh J, Thick M, Dean M. Transplantation of fetal fibroblasts and correction of enzymatic deficiencies in patients with Hunter's or Hurler's disorders. Transplantation 1986; 42:271-4. [PMID: 3092412 DOI: 10.1097/00007890-198609000-00009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
An attempt was made at correcting the specific lysosomal enzyme deficiencies in 7 children with Hunter's or Hurler's diseases by transplantation of fetal fibroblasts. In spite of pretreating the young patients with stored blood, following a procedure employed successfully to avoid rejection of kidneys from incompatible donors, the use of serum-free media for culturing the cells before being harvested and incubation of the cells with chorionic gonadotrophin, the transplantation of fetal fibroblasts was not associated with biochemical or clinical changes. None of the seven patients showed immune reactions against the transplanted cells, HLA antigens, or the missing enzymes.
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485
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Blair DG, Oskarsson MK, Seth A, Dunn KJ, Dean M, Zweig M, Tainsky MA, Vande Woude GF. Analysis of the transforming potential of the human homolog of mos. Cell 1986; 46:785-94. [PMID: 2874888 DOI: 10.1016/0092-8674(86)90354-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The human homolog, c-moshu, of the mouse cellular mos proto-oncogene (c-mosmu) transforms NIH 3T3 cells at low efficiency. Furthermore, the c-moshu-induced foci are less distinct, and transformed cells contain a high level of human mos protein. The transforming activity of hybrid mos genes derived from human and mouse sequences reveals three domains within the coding region, as well as a negative regulatory sequence upstream from the c-moshu ORF that reduces its transforming efficiency. The mos C-terminal region, however, which contains the src-kinase homology domain, appears to have the greatest influence on transforming efficiency. The low transforming efficiency of c-moshu may provide a selective advantage to the host, but it also may indicate a reduced or modified function of mos in humans.
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486
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Dean M, Levine RA, Ran W, Kindy MS, Sonenshein GE, Campisi J. Regulation of c-myc transcription and mRNA abundance by serum growth factors and cell contact. J Biol Chem 1986; 261:9161-6. [PMID: 3722193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
We describe effects of serum insufficiency and cell contact on the transcription and abundance of the c-myc proto-oncogene mRNA in BALB/c 3T3 fibroblasts. In exponentially growing cells, withdrawal of serum caused a 10-fold decline in c-myc mRNA within 90 min. At least part of this decline was due to a decrease in the level of myc gene transcription. These cells became quiescent at subconfluence after 36-40 h. Cells made quiescent at subconfluence or confluence contained low levels of c-myc mRNA which rose more than 20-fold 2 h after stimulation of growth by fresh serum. Thereafter, the mRNA level declined. In subconfluent cells, it declined to the level in exponentially growing cells, i.e. nearly 10-fold over the level in quiescent cells. In confluent cells, by contrast, the mRNA returned to near-quiescent levels within 18 h (by mid-S phase). However, c-myc gene transcription was regulated identically in subconfluent and confluent cultures; quiescent cells transcribed c-myc at detectable levels, and stimulation by serum caused a 5-fold increase in 1 h, followed by a decline to about 2-fold over the quiescent level within 18 h. Thus, confluence affected steady state mRNA levels without affecting the level of transcription. Our results suggest that extracellular conditions that modulate cell proliferation (serum and cell contact) exert strong and rapid control over c-myc mRNA by post-transcriptional and transcriptional mechanisms.
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487
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Dean M, Levine RA, Ran W, Kindy MS, Sonenshein GE, Campisi J. Regulation of c-myc transcription and mRNA abundance by serum growth factors and cell contact. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(18)67633-1] [Citation(s) in RCA: 166] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
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488
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Park M, Dean M, Cooper CS, Schmidt M, O'Brien SJ, Blair DG, Vande Woude GF. Mechanism of met oncogene activation. Cell 1986; 45:895-904. [PMID: 2423252 DOI: 10.1016/0092-8674(86)90564-7] [Citation(s) in RCA: 397] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The met oncogene activated in vitro by treatment of a human osteogenic sarcoma (HOS) cell line with N-methyl-N'-nitronitrosoguanidine (MNNG) is related to the tyrosine kinase gene family. Probes from the met oncogene locus recognize two distinct transcripts of 9.0 kb and 10.0 kb which are independently expressed in a cell-type-specific fashion. While the met proto-oncogene locus expresses the 9.0 kb RNA and maps to human chromosome 7q21-31, the locus expressing the 10.0 kb RNA, (tpr; translocated promoter region) maps to human chromosome 1. Both MNNG-HOS cells and met NIH 3T3 transformants express a novel 5.0 kb RNA which represents a hybrid transcript with 5' sequences derived from tpr and 3' sequences from the met proto-oncogene. Treating HOS cells in vitro with MNNG, a known clastogenic carcinogen, resulted in fusion of two chromosomally disparate loci, met and tpr, generating the active met oncogene.
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489
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Dean M, Levine RA, Campisi J. c-myc regulation during retinoic acid-induced differentiation of F9 cells is posttranscriptional and associated with growth arrest. Mol Cell Biol 1986; 6:518-24. [PMID: 3785153 PMCID: PMC367541 DOI: 10.1128/mcb.6.2.518-524.1986] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
We have shown that c-myc mRNA levels decrease more than 20-fold when F9 teratocarcinoma stem cells are induced to arrest growth and terminally differentiate to parietal endoderm after exposure to retinoic acid and cyclic AMP (Campisi et al., Cell 36:241-247, 1984). Here, we demonstrate that although growth arrest and full expression of the differentiated phenotype required about 3 days, c-myc mRNA declined abruptly between 8 and 16 h after the addition of retinoic acid and cyclic AMP. The decline was independent of cyclic AMP. We found little or no change in the level of c-myc transcription during differentiation, although two other genes showed marked transcriptional regulation. Thus, decreased c-myc mRNA is a consequence of very early posttranscriptional regulation directed by retinoic acid. Differentiation was not fundamental to this regulation. We have shown that sodium butyrate blocks expression of the differentiated phenotype if added within 8 h of retinoic acid and cyclic AMP (Levine et al., Dev. Biol. 105:443-450, 1984). However, butyrate did not inhibit the decrease in c-myc mRNA. Furthermore, F9 cells partially arrested growth without differentiating when grown in isoleucine-deficient medium. Under these conditions, c-myc mRNA levels also declined. Our results suggest that induction of differentiation-specific genes may be under retinoic acid-mediated control dissimilar from that responsible for the decay of c-myc mRNA. In addition, they raise the possibility that growth arrest may be initiated by reduced c-myc expression.
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490
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Park M, Gonzatti-Haces M, Dean M, Blair DG, Testa JR, Bennett DD, Copeland T, Oroszlan S, Vande Woude G. The met oncogene: a new member of the tyrosine kinase family and a marker for cystic fibrosis. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 1986; 51 Pt 2:967-75. [PMID: 3472770 DOI: 10.1101/sqb.1986.051.01.110] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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491
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Ran W, Dean M, Levine RA, Campisi J. Activation of proto-oncogene expression by growth regulatory signals. Curr Top Microbiol Immunol 1986; 132:313-9. [PMID: 3491738 DOI: 10.1007/978-3-642-71562-4_46] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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492
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White R, Woodward S, Leppert M, O'Connell P, Hoff M, Herbst J, Lalouel JM, Dean M, Vande Woude G. A closely linked genetic marker for cystic fibrosis. Nature 1985; 318:382-4. [PMID: 3906407 DOI: 10.1038/318382a0] [Citation(s) in RCA: 283] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Cystic fibrosis is a recessive genetic disorder, characterized clinically by chronic obstructive lung disease, pancreatic insufficiency and elevated sweat electrolytes; affected individuals rarely live past their early twenties. Cystic fibrosis is also one of the most common genetic diseases in the northern European population. The frequency of carriers of mutant alleles in some populations is estimated to be as high as 1 in 20, carrying a concomitant burden of about one affected child in 1,500 births. Because little is known of the essential biochemical defect caused by the mutant gene, a genetic linkage approach based on arbitrary genetic markers and family studies is indicated to determine the chromosomal location of the cystic fibrosis (CF) gene. We have now obtained evidence for tight linkage between the CF locus and a DNA sequence polymorphism at the met oncogene locus. This evidence, combined with the physical localization data for the met locus presented in the accompanying paper, places the CF locus in the middle third of the long arm of chromosome 7, probably between bands q21 and q31.
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493
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Dean M, Park M, Le Beau MM, Robins TS, Diaz MO, Rowley JD, Blair DG, Vande Woude GF. The human met oncogene is related to the tyrosine kinase oncogenes. Nature 1985; 318:385-8. [PMID: 4069211 DOI: 10.1038/318385a0] [Citation(s) in RCA: 235] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The met oncogene was previously isolated from a chemically transformed human cell line, MNNG-HOS. Recent evidence has demonstrated that two classes of transcripts are expressed from the met proto-oncogene locus. The met oncogene, however, expresses an aberrant RNA which has sequences in common with both transcripts. We now report partial nucleotide sequencing of the human met oncogene and show that met is related to the protein kinase oncogenes and growth factor receptors. The met nucleotide sequence is not identical to that of any published gene, and it is more closely homologous to the tyrosine kinases than to the serine/threonine kinases. Within the tyrosine kinase family, the sequenced met domains are most closely related to the human insulin receptor and the viral abl gene. In situ chromosome hybridization has mapped met to human chromosome 7 band 7q21-q31, a location distinct from that of other kinases. This is also a region associated with nonrandom chromosomal deletions observed in a portion of patients with acute nonlymphocytic leukaemia. The accompanying paper shows that this chromosomal locus is also tightly linked with the human heredity disease cystic fibrosis.
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494
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McCormack JE, Pepe VH, Kent RB, Dean M, Marshak-Rothstein A, Sonenshein GE. Specific regulation of c-myc oncogene expression in a murine B-cell lymphoma. Proc Natl Acad Sci U S A 1984; 81:5546-50. [PMID: 6206500 PMCID: PMC391743 DOI: 10.1073/pnas.81.17.5546] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The c-myc oncogene has been implicated in a wide spectrum of B-cell neoplasias. In normal cells, the level of expression of the c-myc gene correlates with growth status. In the present study, we examined the effect of receptor-mediated inhibition of growth on c-myc expression in a B-cell lymphoma. The murine lymphoma line WEHI 231 has been characterized as an early B cell; it bears surface-bound IgM and has unrearranged c-myc genes. Following treatment of a WEHI 231 culture with anti-mouse Ig antiserum, the cells undergo one round of division and further proliferation is inhibited. We observed that this treatment specifically affected cytoplasmic levels of c-myc mRNA. An initial early increase is followed by a precipitous drop such that by 4 hr (after exposure) the amount of c-myc mRNA is below control values by a factor of approximately equal to 10. The drop in c-myc precedes cessation of DNA synthesis. During the 2- to 4-hr period, c-myc mRNA had a maximal half-life of between 20 and 30 min. In contrast, even 24 hr after anti-Ig exposure, the amounts of most major mRNAs, including mu heavy chain and actin, were not significantly altered. These results indicate that expression of an unrearranged c-myc gene can be selectively responsive to receptor-mediated regulatory events.
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495
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Crew JR, Dean M, Johnson JM, Knighton D, Bashour TT, Ellertson D, Hanna ES. Carotid surgery without angiography. Am J Surg 1984; 148:217-20. [PMID: 6465428 DOI: 10.1016/0002-9610(84)90224-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
We propose that circumstances exist in which angiography is not necessary or is unwarranted for the diagnosis and treatment of carotid arterial disease. High quality real-time B-mode ultrasonographic imaging, combined with both pulsed gated, and continuous wave Doppler analysis, shows a remarkably close correlation with the pathologic abnormality identified at operation. Scanning in the vascular laboratory not only provides quick, noninvasive, accurate assessment of the atherosclerotic disease, it can also provide plaque and blood flow detail not previously attainable. Carotid surgery can be effectively and safely performed in selected patients with the aid of ultrasonography and Doppler analysis without the need for invasive angiographic imaging.
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496
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Ponte PA, Dean M, Pepe VH, Sonenshein GE. Overproduction of immunoglobulin mRNA by a murine myeloma MOPC 315 variant cell line. THE JOURNAL OF IMMUNOLOGY 1984. [DOI: 10.4049/jimmunol.133.1.476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
The mouse myeloma MOPC 315 cell line synthesizes and secretes IgA (lambda 2) immunoglobulin. A spontaneously arising variant of the MOPC 315 line, which had been isolated as apparently oversecreting IgA protein, has been characterized. The variant line has been shown to synthesize and secrete increased levels of heavy chain, light chain, and J chain polypeptide compared to the parental wild-type cells from which it was isolated. The steady-state levels of cytoplasmic mRNA for these polypeptides are increased commensurately in the over-producing line. For the heavy chain, enhanced transcription, and possibly increased gene dosage, appear to be involved. The increased levels of the three individual immunoglobulin polypeptide chains suggest that the variant line displays a coordinate regulation of expression of immunoglobulin genes.
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497
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Ponte PA, Dean M, Pepe VH, Sonenshein GE. Overproduction of immunoglobulin mRNA by a murine myeloma MOPC 315 variant cell line. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1984; 133:476-81. [PMID: 6427346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The mouse myeloma MOPC 315 cell line synthesizes and secretes IgA (lambda 2) immunoglobulin. A spontaneously arising variant of the MOPC 315 line, which had been isolated as apparently oversecreting IgA protein, has been characterized. The variant line has been shown to synthesize and secrete increased levels of heavy chain, light chain, and J chain polypeptide compared to the parental wild-type cells from which it was isolated. The steady-state levels of cytoplasmic mRNA for these polypeptides are increased commensurately in the over-producing line. For the heavy chain, enhanced transcription, and possibly increased gene dosage, appear to be involved. The increased levels of the three individual immunoglobulin polypeptide chains suggest that the variant line displays a coordinate regulation of expression of immunoglobulin genes.
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498
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Kakar DN, Dean M, Chopra S. Change of occupation among nurses: a study of factors. THE NURSING JOURNAL OF INDIA 1984; 75:62-3, 55. [PMID: 6564604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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499
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Campisi J, Gray HE, Pardee AB, Dean M, Sonenshein GE. Cell-cycle control of c-myc but not c-ras expression is lost following chemical transformation. Cell 1984; 36:241-7. [PMID: 6692471 DOI: 10.1016/0092-8674(84)90217-4] [Citation(s) in RCA: 643] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Cellular oncogenes are DNA sequences implicated in the genesis of cancer, but their functions in the transformation process are not understood. Our experiments provide data linking expression of two well-studied proto-oncogenes, c-myc and c-rasKi, to current knowledge of proliferation control and its perturbation by differentiation and chemical transformation. Growth stimulation of quiescent cells by serum elevates expression of the myc proto-oncogene in Balb/c 3T3 (A31) cells. In two chemically transformed A31 derivatives (BPA31 and DA31), c-myc expression is constitutive. The levels of c-myc mRNA in quiescent and growing transformed cells are nearly the same, and are only slightly elevated compared to the level found in growing A31 cells. By contrast, c-rasKi expression is cell-cycle-dependent in BPA31 cells. The relative abundance of c-rasKi mRNA begins to increase in mid- to late G0/G1. During terminal differentiation of teratocarcinoma stem cells (F9) into nonproliferating endoderm, relative mRNA abundance is diminished more markedly for c-myc than for c-rasKi. These results demonstrate that expression of the myc and rasKi proto-oncogenes is dependent upon the cellular growth state, and that growth control exhibits growth-factor-dependent, cell-cycle-timed oncogene expression. In the case of the BPA31 cells, c-myc is not rearranged, amplified, or overexpressed. However, the oncogene has lost its cycle-dependent regulation in the chemically transformed cells.
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500
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McCormack JE, Kent RB, Pepe VH, Dean M, Marshak-Rothstein A, Sonenshein GE. Immune regulation of the c-myc oncogene in a murine B lymphoma. Curr Top Microbiol Immunol 1984; 113:127-32. [PMID: 6332712 DOI: 10.1007/978-3-642-69860-6_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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