A spontaneous Cdt1 mutation in 129 mouse strains reveals a regulatory domain restraining replication licensing

作者：Coulombe Philippe; Gregoire Damien; Tsanov Nikolay; Mechali Marcel^*

来源：Nature Communications, 2013, 4(1): 2065.

DOI：10.1038/ncomms3065

Cdt1 is required for loading the replicative DNA helicase MCM2/7, a process known as DNA replication licensing. Here we show that 129 mouse strains express a Cdt1 mutated allele with enhanced licensing activity. The mutation, named Delta(PEST)-P-6, involves a six-amino acid deletion within a previously uncharacterized PEST-like domain. Cdt1 Delta(PEST)-P-6 and more extensive deletions exhibit increased re-replication and transformation activities that are independent of the Geminin and E3 ligase pathways. This PEST domain negatively regulates cell cycledependent chromatin recruitment of Cdt1 in G2/M phases of the cell cycle. Mass spectrometry analysis indicates that Cdt1 is phosphorylated at sites within the deleted PEST domain during mitosis. This study reveals a conserved new regulatory Cdt1 domain crucial for proper DNA licensing activity and suggests a mechanism by which the presence of Cdt1 in G2/M phases does not lead to premature origin licensing. These results also question the usage of 129 mouse strains for knockout analyses.

• 出版日期2013-7