The regulation of competence to replicate in meiosis by Cdc6 is conserved during evolution.
DNA replication licensing is an important step in the cell cycle at which cells become competent for DNA replication. When the cell cycle is arrested for long periods of time, this competence is lost. This is the case for somatic cells arrested in G0 or vertebrate oocytes arrested in G2. CDC6 is a factor involved in replication initiation competence which is necessary for the recruitment of the MCM helicase complex to DNA replication origins. In Xenopus, we have previously shown that CDC6 is the only missing replication factor in the oocyte whose translation during meiotic maturation is necessary and sufficient to confer DNA replication competence to the egg before fertilization (Lemaitre et al., 2002: Mol Biol Cell 13:435-444; Whitmire et al., 2002: Nature 419:722-725). Here, we report that this oogenesis control has been acquired by metazoans during evolution and conserved up to mammals. We also show that, contrary to eukaryotic metazoans, in S. pombe cdc18 (the S. pombe CDC6 homologue), CDC6 protein synthesis is down regulated during meiosis. As such, the lack of cdc18 prevents DNA replication from occurring in spores, whereas the presence of cdc6 makes eggs competent for DNA replication.
Institute of Human Genetics, CNRS, Genome Dynamics and Development, 141, rue de la, Cardonille, 34396 Montpellier, France.
Jean-Marc
JM
Lemaître
Stéphane
S
Bocquet
Marie-Emilie
ME
Terret
Mandana
M
Namdar
Ounissa
O
Aït-Ahmed
Stephen
S
Kearsey
Marie-Hélène
MH
Verlhac
Marcel
M
Méchali
D000818:Animals; D005075:Biological Evolution; D018797:Cell Cycle Proteins / Q000378:metabolism*; D004261:DNA Replication; D004331:Drosophila melanogaster; D005260:Female; D006801:Humans; D008540:Meiosis / Q000502:physiology*; D051379:Mice; D009865:Oocytes / Q000166:cytology / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism; D014982:Xenopus laevis
C066503:CDC6 protein, S cerevisiae; D018797:Cell Cycle Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C082462:cdc18 protein, S pombe