Toggle Main Menu Toggle Search

Open Access padlockePrints

MAP kinase dependent cyclinE/cdk2 activity promotes DNA replication in early sea urchin embryos

Lookup NU author(s): Dr Jolanta Kisielewska, Dr Radka Philipova, Dr Jun-yong Huang, Emeritus Professor Michael Whitaker


Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


Sea urchins provide an excellent model for studying cell cycle control mechanisms governing DNA replication in vivo. Fertilization and cell cycle progression are tightly coordinated by Ca(2+) signals, but the mechanisms underlying the onset of DNA replication after fertilization remain less clear. In this study we demonstrate that calcium-dependent activation of ERK1 promotes accumulation of cyclinE/cdk2 into the male and female pronucleus and entry into first S-phase. We show that cdk2 activity rises quickly after fertilization to a maximum at 4 min, corresponding in timing to the early ERK1 activity peak. Abolishing MAP kinase activity after fertilization with MEK inhibitor, U0126, substantially reduces the early peak of cdk2 activity and prevents cyclinE and cdk2 accumulation in both sperm pronucleus and zygote nucleus in vivo. Both p27(kip1) and roscovitine, cdk2 inhibitors, prevented DNA replication suggesting cdk2 involvement in this process in sea urchin. Inhibition of cdk2 activity using p27(kip1) had no effect on the phosphorylation of MBP by ERK, but completely abolished phosphorylation of retinoblastoma protein, a cdk2 substrate, indicating that cdk2 activity is downstream of ERK1 activation. This pattern of regulation of DNA synthesis conforms to the pattern observed in mammalian somatic cells.

Publication metadata

Author(s): Kisielewska J, Philipova R, Huang JY, Whitaker M

Publication type: Article

Publication status: Published

Journal: Developmental Biology

Year: 2009

Volume: 334

Issue: 2

Pages: 383-394

ISSN (print): 0012-1606

ISSN (electronic): 1095-564X

Publisher: Academic Press


DOI: 10.1016/j.ydbio.2009.07.043


Altmetrics provided by Altmetric