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

P. Coulombe (1) , Grégoire David (2) , N. Tsanov (1) , M. Mechali (1)

1 IGH - Institut de génétique humaine
2 UMR IATE - Ingénierie des Agro-polymères et Technologies Émergentes

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 Δ(6)PEST, involves a six-amino acid deletion within a previously uncharacterized PEST-like domain. Cdt1 Δ(6)PEST 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 cycle-dependent 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.

Domaines: Génétique

P. Coulombe, Grégoire David, N. Tsanov, M. Mechali. A spontaneous Cdt1 mutation in 129 mouse strains reveals a regulatory domain restraining replication licensing. Nature Communications, 2013, 4, pp.2065. ⟨10.1038/ncomms3065⟩. ⟨hal-00852756⟩