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Identification and isolation of maternal procentrosomes from oocytes of Spisula solidissima
Author(s) -
Guo Jing,
Crone Donna,
Hull Dawn,
Wu Xingyong,
Ohta Toshiro,
Kuriyama Ryoko,
Palazzo Robert
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a615-c
Subject(s) - centrosome , oocyte , centriole , meiosis , oocyte activation , microtubule , chemistry , microbiology and biotechnology , human fertilization , biology , biochemistry , cell , genetics , embryo , cell cycle , gene
We have identified maternal centrosome (CE) precursors (procentrosomes (proCEs)) in oocytes of the surf clam Spisula solidissima . Oocytes are arrested at the G2/M border of meiosis I and can be activated to complete meiosis I and II by fertilization or treatment with KCl. No CEs have previously been identified in unactivated oocytes and de novo CE assembly and maturation were thought to be induced by oocyte activation. We isolated CEs from KCl activated oocytes to generate anti‐CE antibodies which recognize an ~300kD CE protein (Spicen). Immunofluorescence with Spicen antibodies revealed the presence of two proCEs in oocytes. Comparison of isolated proCEs to activated CEs revealed a) proCEs are smaller and of lower density as determined by migration in sucrose density gradients, 2) unlike activated CEs, proCEs are unable to nucleate microtubules and 3) proCEs may not contain centrioles while activated CEs clearly do. Importantly, treatment of proCEs with oocyte lysate derived from activated eggs induces microtubule nucleation, while treatment with lysate from unactivated eggs has no affect. We conclude that Spisula oocyte proCEs are induced to undergo maturation including a) recruitment and assembly of CE components to increase CE mass, b) induction of microtubule nucleation potential, and c) the duplication of centrioles upon oocyte activation. Research funded by NIH R01GM043264