Regulation of the retinoblastoma anti-oncogene in aging human diploid fibroblasts.
Cell cycle expression of the retinoblastoma (RB) gene was investigated in young and aging IMR 90 human diploid fibroblasts and in the immortalized but untransformed A31 BALB/c 3T3 mouse fibroblasts. RB RNA levels increased about 75% during late G1/S in both the young and old IMR 90 cells. Young and old cells had similar normalized amounts of RB RNA per cell. Kinase C activation did not stimulate RB transcription. The A31 cells showed a constant RB RNA level throughout G0/S. The data is consistent with the hypothesis that RB activity is regulated primarily post-transcriptionally and indicates that a change in the regulation of RB transcription is not part of the senescence phenomenon.
Shigeoka
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Division of Medical Oncology, Harbor-UCLA Medical Center, Torrance 90509.
Yang
H C
HC
D000818:Animals; D002453:Cell Cycle / Q000235:genetics; D002470:Cell Survival / Q000235:genetics; D004171:Diploidy; D005347:Fibroblasts / Q000166:cytology; D015972:Gene Expression Regulation, Neoplastic; D016161:Genes, Retinoblastoma / Q000235:genetics*; D016147:Genes, Tumor Suppressor / Q000235:genetics*; D006801:Humans; D051379:Mice; D012334:RNA, Neoplasm / Q000032:analysis; D014158:Transcription, Genetic / Q000235:genetics*
D012334:RNA, Neoplasm