title: Cell-specific regulation of the c-myc gene by lymphocyte mitogens and platelet-derived growth factor.
abstract: We show that c-myc is an inducible gene that is regulated by specific growth signals in a cell-cycle-dependent manner. Specifically, agents that initiate the first phase of a proliferative response in lymphocytes (lipopolysaccharide or Concanavalin A) and fibroblasts (platelet-derived growth factor) induce c-myc mRNA. Within one to three hr after the addition of these mitogens to the appropriate cells, c-myc mRNA concentration is increased between 10- and 40-fold. This induction of c-myc mRNA occurs in the presence of cycloheximide and, therefore, does not require the synthesis of new protein species. Consequently, the induction of c-myc mRNA is not secondary to growth. In addition, c-myc mRNA is "superinduced" by the combination of cycloheximide and mitogen, a finding consistent with a model that a labile protein may regulate c-myc levels in these cells. Further, this work suggests a regulatory linkage between the function of two oncogenes--c-myc and c-sis--the latter being the putative structural gene for PDGF.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology; D002453:Cell Cycle; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects*; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008934:Mitogens / Q000494:pharmacology*; D009857:Oncogenes; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics; D013601:T-Lymphocytes / Q000502:physiology
chemical_list: D008934:Mitogens; D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger; D003513:Cycloheximide