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Spontaneous calcium oscillations and nuclear PLC‐β1 in human GV oocytes
Author(s) -
Miyara F.,
Pesty A.,
Migne C.,
Djediat C.,
Huang X.B.,
DumontHassan M.,
Debey P.,
Lefèvre B.
Publication year - 2008
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.20749
Subject(s) - germinal vesicle , biology , microbiology and biotechnology , chromatin , oocyte , chromosomal translocation , nucleolus , cytoplasm , meiosis , in vitro maturation , genetics , embryo , gene
Our aim was to investigate if human oocytes, like mouse oocytes, exhibit spontaneous Ca 2+ oscillations and nuclear translocation of PLC‐β1 prior to germinal vesicle breakdown (GVBD), and to correlate these events with the evolution of chromatin configuration as a landmark for the meiosis resumption kinetics. Human germinal vesicle (GV) oocytes were either loaded with Fluo‐3 probe to record Ca 2+ signals or fixed for subsequent fluorescent labeling of both chromatin and PLC‐β1, and immunogold labeling of PLC‐β1. Here for the first time, we show that human oocytes at the GV‐stage exhibit spontaneous Ca 2+ oscillations. Interestingly, only oocytes with a large diameter and characterized by a compact chromatin surrounding the nucleolus of the GV could reveal these kind of oscillations. We also observed a translocation of PLC‐β1 from the cytoplasm towards the nucleus during in vitro maturation of human oocytes. Spontaneous calcium oscillations and nuclear translocation of PLC‐β1 may reflect some degree of oocyte maturity. The impact of our results may be very helpful to understand and resolve many enigmatic problems usually encountered during the in vitro meiotic maturation of human GV oocytes. Mol. Reprod. Dev. 75: 392–402, 2008. © 2007 Wiley‐Liss, Inc.