title: Regulation of DNA Replication in Early Embryonic Cleavages.
abstract: Early embryonic cleavages are characterized by short and highly synchronous cell cycles made of alternating S- and M-phases with virtually absent gap phases. In this contracted cell cycle, the duration of DNA synthesis can be extraordinarily short. Depending on the organism, the whole genome of an embryo is replicated at a speed that is between 20 to 60 times faster than that of a somatic cell. Because transcription in the early embryo is repressed, DNA synthesis relies on a large stockpile of maternally supplied proteins stored in the egg representing most, if not all, cellular genes. In addition, in early embryonic cell cycles, both replication and DNA damage checkpoints are inefficient. In this article, we will review current knowledge on how DNA synthesis is regulated in early embryos and discuss possible consequences of replicating chromosomes with little or no quality control.
authors.affiliation: Genome Surveillance and Stability Laboratory, Institute of Human Genetics, UMR9002-CNRS-UM, 141 rue de la Cardonille, Montpellier 34396, France. chames.kermi@igh.cnrs.fr.
authors.forename: Chames
authors.initials: C
authors.lastname: Kermi
authors.affiliation: Genome Surveillance and Stability Laboratory, Institute of Human Genetics, UMR9002-CNRS-UM, 141 rue de la Cardonille, Montpellier 34396, France. elena.lo-furno@igh.cnrs.fr.
authors.forename: Elena
authors.initials: E
authors.lastname: Lo Furno
authors.affiliation: Genome Surveillance and Stability Laboratory, Institute of Human Genetics, UMR9002-CNRS-UM, 141 rue de la Cardonille, Montpellier 34396, France. domenico.maiorano@igh.cnrs.fr.
authors.forename: Domenico
authors.initials: D
authors.lastname: Maiorano
keywords: Drosophila; S-phase; Xenopus; cell cycle; checkpoint; development; translesion synthesis