Adolfi Mateus C, Herpin Amaury, Regensburger Martina, Sacquegno Jacopo, Waxman Joshua S, Schartl Manfred
University of Wuerzburg, Physiological Chemistry, Biocenter, Am Hubland, D-97074 Wuerzburg, Germany.
INRA, UR1037, Fish Physiology and Genomics, Rennes F-35000, France.
Sci Rep. 2016 Sep 28;6:34281. doi: 10.1038/srep34281.
In vertebrates, one of the first recognizable sex differences in embryos is the onset of meiosis, known to be regulated by retinoic acid (RA) in mammals. We investigated in medaka a possible meiotic function of RA during the embryonic sex determination (SD) period and in mature gonads. We found RA mediated transcriptional activation in germ cells of both sexes much earlier than the SD stage, however, no such activity during the critical stages of SD. In adults, expression of the RA metabolizing enzymes indicates sexually dimorphic RA levels. In testis, RA acts directly in Sertoli, Leydig and pre-meiotic germ cells. In ovaries, RA transcriptional activity is highest in meiotic oocytes. Our results show that RA plays an important role in meiosis induction and gametogenesis in adult medaka but contrary to common expectations, not for initiating the first meiosis in female germ cells at the SD stage.
在脊椎动物中，胚胎中最早可识别的性别差异之一是减数分裂的开始，已知在哺乳动物中这一过程受视黄酸（RA）调控。我们在青鳉中研究了视黄酸在胚胎性别决定（SD）期和成熟性腺中的潜在减数分裂功能。我们发现，视黄酸介导的转录激活在两性生殖细胞中比性别决定阶段要早得多，但在性别决定的关键阶段没有这种活性。在成年个体中，视黄酸代谢酶的表达表明视黄酸水平存在性别差异。在睾丸中，视黄酸直接作用于支持细胞、间质细胞和减数分裂前的生殖细胞。在卵巢中，视黄酸转录活性在减数分裂期卵母细胞中最高。我们的结果表明，视黄酸在成年青鳉的减数分裂诱导和配子发生中起重要作用，但与普遍预期相反，它在性别决定阶段并非启动雌性生殖细胞的第一次减数分裂所必需。
