Publication Date:
1990-08-10
Description:
Heterokaryon studies suggest that senescent and quiescent human diploid fibroblasts (HDF) contain a common inhibitor of entry into S phase. DNA synthesis can be induced in senescent and quiescent HDF by fusing them with cells containing DNA viral oncogenes such as SV40 T antigen, adenovirus E1A, or human papillomavirus E7. Both senescent and quiescent HDF contained the unphosphorylated form (p110Rb) of the retinoblastoma protein, a putative inhibitor of proliferation. After serum stimulation, senescent HDF did not phosphorylate p110Rb and did not enter S phase, whereas quiescent HDF phosphorylated p110Rb and entered S phase. These findings, combined with the observations that T antigen, E1A, and E7 form complexes with, and presumably inactivate, unphosphorylated p110Rb, suggest that failure to phosphorylate p110Rb may be an immediate cause of failure to enter S phase in senescent HDF.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Stein, G H -- Beeson, M -- Gordon, L -- AG 00947/AG/NIA NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 10;249(4969):666-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder 80309-0347.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2166342" target="_blank"〉PubMed〈/a〉
Keywords:
Adenovirus Early Proteins
;
Antigens, Polyomavirus Transforming/genetics
;
Cell Division
;
Cell Line
;
Fibroblasts/cytology/metabolism
;
Humans
;
Interphase
;
Molecular Weight
;
Nuclear Proteins/*metabolism
;
Oncogene Proteins, Viral/metabolism
;
Oncogenes
;
Papillomaviridae/genetics
;
Phosphoproteins/isolation & purification/*metabolism
;
Phosphorylation
;
Retinoblastoma Protein
;
Simian virus 40/genetics/immunology
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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