Serum and growth factors stimulate ribosomal RNA processing in Syrian hamster embryo cells: divergence of this signalling pathway from immediate-early gene expression.
Growth factor stimulation of cells results in multiple intracellular biochemical changes including increases in calcium levels, phosphatidylinositol turnover, protein phosphorylation, immediate-early gene transcription and intracellular pH alterations. We report here that serum and growth factor stimulation of Syrian hamster embryo (SHE)-derived cell lines increases the ribosomal RNA (rRNA) processing rates. In addition, in several transformed SHE cell lines, the immediate-early response of fos/actin transcription could be separated from the immediate-early rRNA processing response. These results indicate that in these cell lines a mutation(s) which uncouples these responses has occurred. This is the first report describing (i) rRNA processing as an immediate-early effect following growth factor stimulation and (ii) the identification of a mutation(s) which can uncouple two immediate-early signalling responses.
Isfort
R J
RJ
Human and Environmental Safety Division, Procter & Gamble Co., Cincinnati, OH 45239-8707.
Cody
D B
DB
D000199:Actins / Q000235:genetics; D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D003470:Culture Media; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism; D015870:Gene Expression; D016762:Genes, fos; D006133:Growth Substances / Q000494:pharmacology; D008647:Mesocricetus; D009154:Mutation; D012323:RNA Processing, Post-Transcriptional / Q000187:drug effects; D012335:RNA, Ribosomal / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014158:Transcription, Genetic
D000199:Actins; D003470:Culture Media; D006133:Growth Substances; D012335:RNA, Ribosomal