Identification of the nuclear localization signal in Xenopus cyclin E and analysis of its role in replication and mitosis.

Journal Article (Journal Article)

Cyclin-dependent kinase (Cdk)2/cyclin E is imported into nuclei assembled in Xenopus egg extracts by a pathway that requires importin-alpha and -beta. Here, we identify a basic nuclear localization sequence (NLS) in the N-terminus of Xenopus cyclin E. Mutation of the NLS eliminated nuclear accumulation of both cyclin E and Cdk2, and such versions of cyclin E were unable to trigger DNA replication. Addition of a heterologous NLS from SV40 large T antigen restored both nuclear targeting of Cdk2/cyclin E and DNA replication. We present evidence indicating that Cdk2/cyclin E complexes must become highly concentrated within nuclei to support replication and find that cyclin A can trigger replication at much lower intranuclear concentrations. We confirmed that depletion of endogenous cyclin E increases the concentration of cyclin B necessary to promote entry into mitosis. In contrast to its inability to promote DNA replication, cyclin E lacking its NLS was able to cooperate with cyclin B in promoting mitotic entry.

Full Text

Duke Authors

Cited Authors

  • Moore, JD; Kornbluth, S; Hunt, T

Published Date

  • December 2002

Published In

Volume / Issue

  • 13 / 12

Start / End Page

  • 4388 - 4400

PubMed ID

  • 12475960

Pubmed Central ID

  • PMC138641

Electronic International Standard Serial Number (EISSN)

  • 1939-4586

International Standard Serial Number (ISSN)

  • 1059-1524

Digital Object Identifier (DOI)

  • 10.1091/mbc.e02-07-0449


  • eng