title: Regulation of the retinoblastoma anti-oncogene in aging human diploid fibroblasts.
abstract: 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.
authors.affiliation: Division of Medical Oncology, Harbor-UCLA Medical Center, Torrance 90509.
authors.forename: H
authors.initials: H
authors.lastname: Shigeoka
authors.forename: H C
authors.initials: HC
authors.lastname: Yang
mesh_terms: 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*
chemical_list: D012334:RNA, Neoplasm