Cyclin E/Cdk2 is required for sperm maturation, but not DNA replication, in early sea urchin embryos

Academic Article


  • The cell cycle is driven by the activity of cyclin/cdk complexes. In somatic cells, cyclin E/cdk2 oscillates throughout the cell cycle and has been shown to promote S-phase entry and initiation of DNA replication. In contrast, cyclin E/cdk2 activity remains constant throughout the early embryonic development of the sea urchin and localizes to the sperm nucleus following fertilization. We now show that cyclin E localization to the sperm nucleus following fertilization is not unique to the sea urchin, but also occurs in the surf clam, and inhibition of cyclin E/cdk2 activity by roscovitine inhibits the morphological changes indicative of male pronuclear maturation in sea urchin zygotes. Finally, we show that inhibition of cyclin E/cdk2 activity does not block DNA replication in the early cleavage cycles of the sea urchin. We conclude that cyclin E/cdk2 activity is required for male pronuclear maturation, but not for initiation of DNA replication in early sea urchin development. © 2007 Wiley-Liss, Inc.
  • Authors

    Digital Object Identifier (doi)

    Author List

  • Schnackenberg BJ; Palazzo RE; Marzluff WF
  • Start Page

  • 282
  • End Page

  • 291
  • Volume

  • 45
  • Issue

  • 5