Protooncogene junB as a target for activin actions.
Activin, a member of the transforming growth factor-beta family of peptides, is implicated in the regulation of cell growth and differentiation in a variety of biological systems. We have sought to identify immediate early genes whose altered expression may provide a common nuclear event involved in activin-regulated phenotypic changes in many cell types. In both human K562 myelogenous leukemia and rat PC12 pheochromocytoma cells, activin treatment caused transient transcription-dependent and protein synthesis-independent increases of junB messenger RNA (mRNA) within 1 h, whereas neither c-jun nor c-fos mRNA were inducible. In K562 cells, this selective junB mRNA induction was synergistically augmented by treatment with 12-O-tetradecanoyl phorbol-13-acetate but not affected by forskolin. Furthermore, in PC12 cells, the up-regulation of junB mRNA by activin was observable even after high-dose treatment with 12-O-tetradecanoyl phorbol-13-acetate for 48 h, indicating that junB mRNA expression by activin is independent of both A- and C-kinases. Our report suggests that induction of this ubiquitous gene product may be a critical event shared by a set of activin-responsive tissues.
Hashimoto
M
M
Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, California 92037-1099.
Gaddy-Kurten
D
D
Vale
W
W
D028341:Activins; D000818:Animals; D004357:Drug Synergism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D017781:Genes, Immediate-Early; D016758:Genes, jun / Q000187:drug effects*; D006801:Humans; D007265:Inhibins / Q000494:pharmacology*; D007700:Kinetics; D007951:Leukemia, Myeloid; D016716:PC12 Cells; D011493:Protein Kinase C / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D012333:RNA, Messenger; D028341:Activins; D007265:Inhibins; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate