Document Detail

Activation of p21ras is not sufficient to ensure a complete G1 phase of the cell division cycle in mouse fibroblasts.
MedLine Citation:
PMID:  8950978     Owner:  NLM     Status:  MEDLINE    
In the mouse BP-A31 fibroblasts, mRNAs coding the three isoforms (Ha, Ki, N) of ras are expressed, and there are no activating mutations in the codons 12, 13 or 61. We have produced a subline (Ras2) expressing an oestrogen-inducible v-Ha-ras gene. The contribution of v-Ha-ras to the overall p21ras-GTP content was evaluated by metabolic labelling with 32P. Surprisingly, p21ras-GTP complexes were predominant in the serum-deprived BP-A31 cells as well as in the Ras2 cells. The excess of p21ras-GTP was not due to the lack of the GTPase activating protein. In transient transfection experiments, the serum response element (SRE)-directed CAT was expressed in serum-deprived BP-A31 cells, and insulin caused a further two- to threefold increase in CAT activity. A dominant negative ras mutant (Ha-Ras Asn-17) cancelled both the basal and insulin-induced CAT expression in the BP-A31 but not in the Ras2 cells. Expression of v-Ha-ras in Ras2 cells did not relax their growth factor-dependence and oestradiol had only a minor mitogenic effect. We conclude that p21ras activation does not ensure a complete cell division cycle in these cells, and does not entirely account for the transduction of the mitogenic signal initiated by insulin.
A M Gaben; C Saucier; M Bedin; V Barbu; D Courilleau; D H Bon-Hoa; J Mester
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Oncogene     Volume:  13     ISSN:  0950-9232     ISO Abbreviation:  Oncogene     Publication Date:  1996 Nov 
Date Detail:
Created Date:  1997-01-09     Completed Date:  1997-01-09     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8711562     Medline TA:  Oncogene     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  2113-20     Citation Subset:  IM    
INSERM U55, Hôpital St Antoine, Paris, France.
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MeSH Terms
Cell Line
Chloramphenicol O-Acetyltransferase / genetics,  metabolism
Culture Media, Serum-Free
Fibroblasts / cytology
G1 Phase / genetics,  physiology*
Genes, ras / physiology*
Guanosine Triphosphate / metabolism*
Insulin / pharmacology
Oncogene Protein p21(ras) / genetics,  metabolism*
RNA, Messenger / metabolism
Reg. No./Substance:
0/Culture Media, Serum-Free; 0/RNA, Messenger; 11061-68-0/Insulin; 86-01-1/Guanosine Triphosphate; EC O-Acetyltransferase; EC Protein p21(ras)

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