Abstract
The evolutionarily conserved partitioning defective (PAR) protein PAR-3 is pivotal for establishing and maintaining cell polarity. During mammalian oocyte maturation, the radially symmetric oocyte is transformed into a highly polarized metaphase II (MII)-arrested egg. We therefore examined several aspects of PAR-3 expression during oocyte maturation. We cloned two novel PAR-3 transcripts from an oocyte library that likely encode proteins of Mr = 73 K and 133 K that are phosphorylated during maturation. PAR-3, which is found throughout the GV-intact oocyte, becomes asymmetrically localized during meiosis. Following germinal vesicle breakdown, PAR-3 surrounds the condensing chromosomes and associates with the meiotic spindles. Prior to emission of the first and second polar bodies, PAR-3 is located within a central subdomain of the polarized actin cap, which overlies the spindle. This cortical PAR-3 localization depends on intact microfilaments. These results suggest a role for PAR-3 in establishing asymmetry in the egg and in defining the future site of polar body emission.
Original language | English (US) |
---|---|
Pages (from-to) | 38-47 |
Number of pages | 10 |
Journal | Developmental Biology |
Volume | 280 |
Issue number | 1 |
DOIs | |
State | Published - Apr 1 2005 |
Funding
This research was supported by grants from the NIH (HD22732 to R.M.S. and C.J.W. and HD06274 to S.B.M.). F.D. was supported by the National Science Foundation Graduate Research Fellowship. We thank Teri Ord and Kerry Krauss for technical assistance and advice. The oocyte cDNA library was a generous gift from John J. Eppig and the C2-2 antibody was a generous gift from S. Ohno. Portions of this work are being submitted by F.D. in partial fulfillment for the Ph.D. requirements at the University of Pennsylvania.
Keywords
- Cortical actin
- Meiosis
- Mouse egg
- PAR-3
ASJC Scopus subject areas
- Molecular Biology
- Developmental Biology
- Cell Biology