Control of the Cell Cycle in Early Embryos (original) (raw)

1. J. Ruderman*,
2. F. Luca*,
3. E. Shibuya*,
4. K. Gavin*,
5. T. Boulton*, and
6. M. Cobb†
7. *Department of Anatomy and Cell Biology, Harvard Medical School, Boston, Massachusetts 02115; †Department of Pharmacology, University of Texas Southwestern Medical School, Dallas, Texas 75235

Excerpt

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.

Oocytes of marine invertebrates provide excellent material for identifying some of the molecules involved in regulating the cell cycle. The full-grown oocytes contain large stockpiles of virtually all the enzymes and structural proteins needed to sustain the rapid, post-fertilization cleavage division cycles, yet they remain arrested. Their responses to fertilization are abrupt, synchronous and, most important, dramatically...