Mastering Early Divisions

摘要

The regulation of canonical mitotic cell cycles is well understood, but the basic principles of the rapid, synchronized early mitotic divisions in embryos remains a mystery. Early embryos lack key mitotic regulators such as checkpoints, the anaphase-promoting complex/cyclosome (APC/C)-inhibitory protein Emi1, and the inhibitory phosphorylations of cyclin-dependent kinase 1 (Cdk1). Working in Xenopus embryos, Tischer et al. (p. 520, published online 27 September) identified XErp1/Emi2 as a mitotic APC/C-inhibitor essential for early mitotic divisions.