Maintenance of sister-chromatid cohesion at the centromere by the Drosophila MEI-S332 protein (original) (raw)
- Tracy Tzu-Ling Tang,
- Sharon E. Bickel1,
- Lynn M. Young2, and
- Terry L. Orr-Weaver3
- Whitehead Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts USA 02142
Abstract
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.
Footnotes
Present addresses: 1Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755 USA;2Exelixis Pharmaceuticals, Inc., South San Francisco, California 94080 USA.
↵3 Corresponding author.
E-MAIL weaver{at}wi.mit.edu; FAX (617) 258-9872.
- Received August 10, 1998.
- Accepted October 20, 1998.
Cold Spring Harbor Laboratory Press