Cell cycle regulation of the replication licensing system: involvement of a Cdk-dependent inhibitor

Mahbubani, Hiro M., Chong, James P. J., Chevalier, Stephane, Thömmes, Pia and Blow, J. Julian (1997) Cell cycle regulation of the replication licensing system: involvement of a Cdk-dependent inhibitor. Journal of Cell Biology, 136 (1). pp. 125-135. ISSN 0021-9525

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The replication licensing factor (RLF) is an essential initiation factor that is involved in preventing re-replication of chromosomal DNA in a single cell cycle. In Xenopus egg extracts, it can be separated into two components: RLF-M, a complex of MCM/P1 polypeptides, and RLF-B, which is currently unpurified. In this paper we investigate variations in RLF activity throughout the cell cycle. Total RLF activity is low in metaphase, due to a lack of RLF-B activity and the presence of an RLF inhibitor. RLF-B is rapidly activated on exit from metaphase, and then declines during interphase. The RLF inhibitor present in metaphase extracts is dependent on the activity of cyclin-dependent kinases (Cdks). Affinity depletion of Cdks from metaphase extracts removed the RLF inhibitor, while Cdc2/cyclin B directly inhibited RLF activity. In metaphase extracts treated with the protein kinase inhibitor 6-dimethylaminopurine (6-DMAP), both cyclin B and the RLF inhibitor were stabilized although the extracts morphologically entered interphase. These results are consistent with studies in other organisms that invoke a key role for Cdks in preventing re-replication of DNA in a single cell cycle.

Item Type: Article
Faculty \ School:
Depositing User: LivePure Connector
Date Deposited: 11 Jun 2024 09:30
Last Modified: 11 Jun 2024 09:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/95541
DOI: 10.1083/jcb.136.1.125

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