Control of the Cell Cycle in Early Embryos

Abstract

At the end of oogenesis, oocytes exit from the cell cycle and arrest at the G2/M border of meiosis I. In clams, fertilization provides the extracellular signal that breaks this cell cycle arrest and initiates a series of rapid cell division cycles. In this paper, we consider two aspects of this process: the rapid, one-time activation of a member of the ERK/MAP kinase family that appears to be a key player in breaking cell cycle arrest, and the repetitive role of cyclin accumulation and destruction in driving cycles of cdc2/28 activation and inactivation.