c-fos expression is neither sufficient nor obligatory for differentiation of monomyelocytes to macrophages.
The c-fos gene is rapidly and transiently expressed when human U-937 and HL-60 leukemia cells are induced to differentiate to macrophages. We show that the expression of c-fos is controlled primarily at the transcriptional level. c-fos mRNA is very labile, with a half-life of less than 30 min. Superinduction of c-fos in the presence of cycloheximide occurs primarily because of stabilization of c-fos mRNA. When U-937 cells are serum-stimulated or treated with diacylglycerol, a c-kinase agonist, c-fos is transiently expressed to high levels; however, the cells fail to differentiate to macrophages. Furthermore, HL-60 cell variants resistant to TPA can be induced to differentiate to macrophages in the absence of detectable c-fos expression.
D002117:Calcitriol / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology; D004075:Diglycerides / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D015470:Leukemia, Myeloid, Acute / Q000473:pathology; D008264:Macrophages / Q000473:pathology*; D009000:Monocytes / Q000473:pathology*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger / Q000032:analysis; D012334:RNA, Neoplasm / Q000032:analysis; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D004075:Diglycerides; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D003513:Cycloheximide; D002117:Calcitriol; D013755:Tetradecanoylphorbol Acetate