Maintenance of sister-chromatid cohesion at the centromere by the Drosophila MEI-S332 protein.
Sister-chromatid cohesion is essential for the faithful segregation of chromosomes during cell division. Recently biochemical analysis with Xenopus extracts suggests that cohesion is established during S phase by a cohesion complex but that other proteins must maintain it in mitosis. The Drosophila melanogaster MEI-S332 protein is present on centromeres in mitosis and meiosis and is essential for cohesion at the centromeres in meiosis II. Here, we analyze the timing of MEI-S332 assembly onto centromeres and the functional domains of the MEI-S332 protein. We find that MEI-S332 is first detectable on chromosomes during prometaphase, and this localization is independent of microtubules. MEI-S332 contains two separable functional domains, as mutations within these domains show intragenic complementation. The carboxy-terminal basic region is required for chromosomal localization. The amino-terminal coiled-coil domain may facilitate protein-protein interactions between MEI-S332 and male meiotic proteins. MEI-S332 interacts with itself in the yeast two-hybrid assay and in immunoprecipitates from Drosophila oocyte and embryo extracts. Thus it appears that MEI-S332 assembles into a multimeric protein complex that localizes to centromeric regions during prometaphase and is required for the maintenance of sister-chromatid cohesion until anaphase, rather than its establishment in S phase.
Tang
T T
TT
Whitehead Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts USA 02142, USA.
Bickel
S E
SE
Young
L M
LM
Orr-Weaver
T L
TL
D019943:Amino Acid Substitution; D000818:Animals; D018797:Cell Cycle Proteins; D002503:Centromere / Q000378:metabolism*; D002842:Chromatids / Q000378:metabolism*; D002875:Chromosomes / Q000378:metabolism; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005816:Genetic Complementation Test; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008540:Meiosis; D008677:Metaphase; D008870:Microtubules / Q000502:physiology; D008938:Mitosis; D020125:Mutation, Missense; D009630:Nondisjunction, Genetic; D009865:Oocytes; D011485:Protein Binding; D017433:Protein Structure, Secondary; D012441:Saccharomyces cerevisiae; D013090:Spermatocytes; D008941:Spindle Apparatus / Q000502:physiology
D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; C096223:mei-S332 protein, Drosophila