Expression of survivin in human oocytes and preimplantation embryos

Capsule:
The study demonstrated that a specific survivin mRNA and protein are expressed in human oocytes and embryos. Embryos secrete survivin into culture media, and survivin concentrations are positively correlated with embryo cleavage rates.

Authors:
Hanna Balakier, Ph.D., Rong Xiao, M.Sc., John Zhao, M.Sc., Shirin Zaver, B.Sc., Ewa Dziak, M.Sc., Katarzyna Szczepanska, Ph.D., Michal Opas, Ph.D., Shang-mian Yie, Ph.D., Clifford Librach, M.D.

Volume 99, Issue 2, Pages 518-525, February 2013

Abstract:

Objective:
To determine whether 1) survivin is expressed in human oocytes and embryos; 2) embryos grown in vitro secrete survivin protein; and 3) survivin levels are correlated with embryo cleavage rates.

Design:
Experimental.

Setting:
University-affiliated IVF clinic.

Patient(s):
Couples undergoing IVF-ET cycles.

Intervention(s):
Conventional reverse transcriptase–polymerase chain reaction (PCR), real-time PCR, immunohistochemistry, Western blot on oocytes, embryos and control choriocarcinoma JEG-3 cells, and ELISA analysis of conditioned culture media.

Main Outcome Measure(s):
Detection of survivin mRNA and protein in oocytes and preimplantation embryos, and in JEG-3 cancer cells. Detection of survivin concentrations in embryo culture media.

Result(s):
Survivin mRNA and protein were expressed during human oocyte maturation, from GV to MII stage, and throughout embryo development, from pronuclear stage to blastocyst stage. Survivin was localized predominantly in the cytoplasm of all cells examined, and in oocytes on the chromatin of metaphase chromosomes and midbodies. Western blot analysis of human oocyte and cancer cell extracts detected a full-length (primary) survivin band of 16.5 kDa. Survivin was also detected in conditioned media samples from embryo cultures and showed a positive correlation with embryo cleavage rates.

Conclusion:
Our data has demonstrated, for the first time, that both human oocytes/embryos express and secret survivin, suggesting that survivin may play an important role in human oogenesis and embryogenesis.

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