RRC ID 4214
Author Budirahardja Y, Gönczy P.
Title PLK-1 asymmetry contributes to asynchronous cell division of C. elegans embryos.
Journal Development
Abstract Acquisition of lineage-specific cell cycle duration is an important feature of metazoan development. In Caenorhabditis elegans, differences in cell cycle duration are already apparent in two-cell stage embryos, when the larger anterior blastomere AB divides before the smaller posterior blastomere P1. This time difference is under the control of anterior-posterior (A-P) polarity cues set by the PAR proteins. The mechanisms by which these cues regulate the cell cycle machinery differentially in AB and P1 are incompletely understood. Previous work established that retardation of P1 cell division is due in part to preferential activation of an ATL-1/CHK-1 dependent checkpoint in P1, but how the remaining time difference is controlled is not known. Here, we establish that differential timing relies also on a mechanism that promotes mitosis onset preferentially in AB. The polo-like kinase PLK-1, a positive regulator of mitotic entry, is distributed in an asymmetric manner in two-cell stage embryos, with more protein present in AB than in P1. We find that PLK-1 asymmetry is regulated by A-P polarity cues through preferential protein retention in the embryo anterior. Importantly, mild inactivation of plk-1 by RNAi delays entry into mitosis in P1, but not in AB, in a manner that is independent of ATL-1/CHK-1. Together, our findings support a model in which differential timing of mitotic entry in C. elegans embryos relies on two complementary mechanisms: ATL-1/CHK-1-dependent preferential retardation in P1 and PLK-1-dependent preferential promotion in AB, which together couple polarity cues and cell cycle progression during early development.
Volume 135(7)
Pages 1303-13
Published 2008-4
DOI 10.1242/dev.019075
PII dev.019075
PMID 18305005
MeSH Animals Animals, Genetically Modified Caenorhabditis elegans / cytology Caenorhabditis elegans / embryology* Caenorhabditis elegans / physiology* Cell Cycle Proteins / metabolism* Cell Division* Cell Polarity / genetics Embryo, Nonmammalian / cytology Embryo, Nonmammalian / metabolism Mitosis / physiology Models, Biological Protein-Serine-Threonine Kinases / metabolism* Proto-Oncogene Proteins / metabolism*
IF 5.413
Times Cited 37
C.elegans tm853