Regulation of Oocyte Maturation in Zebrafish by Zinc and Androgen
Refereed conference paper presented and published in conference proceedings

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AbstractThe availability of zinc plays an important role in oocyte development and function. Our initial data indicated that the action of zinc on meiotic resumption from meiosis I in oocyte maturation is very different between fish and mammals. In addition, zinc is found to be involved in luteinizing hormone (LH)-induced androgen-mediated oocyte maturation in zebrafish. Total zinc concentration increased during ovarian follicle growth and maturation. In vitro treatment of ZnCl2 or ZnSO4 of either intact or denuded full grown oocytes significantly induced germinal vesicle breakdown (GVBD) in a time-, dose- and stage-dependent manner. Zinc depletion significantly blocked GVBD, and this can be rescued by zinc supplementation. The oocyte maturation defects observed in the LH β-subunit homozygous mutant (lhb-/-) could be rescued by zinc and testosterone. Testosterone can significantly induce GVBD in vitro and in vivo, and increase total zinc content in full grown follicles. In vitro testosterone treatment of primary follicular cells in culture and in vivo intraperitoneal injection of hCG can significantly increase zinc content in ovarian follicular cells. In vitro TPEN treatment can block testosterone-induced GVBD in full grown follicles suggesting the involvement of zinc in androgen-induced oocyte maturation. We have also analyzed several potential downstream pathways of androgen/zinc-dependent oocyte maturation. Data of in vitro treatment of nuclear androgen receptor antagonist flutamide, calcium chelator BAPTA, PKC inhibitor Calphostin C indicated no involvement of nuclear androgen receptor, calcium signaling or PKC pathway in androgen/zinc-dependent oocyte maturation. Androgen-induced oocyte maturation can be blocked by treatment of protein synthesis inhibitor cycloheximide but not by transcription inhibitor actinomycin D, suggesting that androgen induces oocyte maturation via a non-genomic mechanism. In vitro treatment MEK1/2 inhibitor U0126 significantly inhibited the action of testosterone/zinc in inducing GVBD, suggesting that androgen/zinc induces oocyte maturation via MAPK signaling. Our study provides evidence for a novel pathway in regulating oocyte maturation in zebrafish.
All Author(s) ListDuo HUANG, Jianzhen LI, Christopher H.K. CHENG
Name of ConferenceThe Fifth Zebrafish Research Conference of China - Developmental Genetics and Disease Models
Start Date of Conference29/10/2017
End Date of Conference01/11/2017
Place of ConferenceWuzhen
Country/Region of ConferenceChina
LanguagesEnglish-United States

Last updated on 2018-07-05 at 11:47