Cyclin A2 transcriptional regulation: Modulation of cell cycle control at the G1/S transition by peripheral cues

Several types of cyclins have been identified and among these, cyclin A2 is synthesized in somatic cells at the onset of DNA synthesis as well as duri ng the G2/M transition associated with cyclin-dependent protein kinases 1 a nd 2. Modulation of cyclin A transcription is due to the interplay between a cell cycle-dependent periodic relief of a transcriptional repression and signals transduced through adenosine 3',5'-cyclic monophosphate, transformi ng growth factor-beta, and the integrin-mediated pathways. Using primary mo use embryonic fibroblasts from embryos where the genes coding for the prote in responsible for susceptibility to retinoblastoma (pRB) and the related p 107 and p130 proteins had been individually inactivated, we showed that cyc lin A is a functional target of pRB-mediated cell cycle arrest. The factors involved are discussed. BIOCHEM PHARMACOL 60;8:1179-1184, 2000. (C) 2000 E lsevier Science Inc.