Gnrh3 Regulates PGC Proliferation and Sex Differentiation in Developing Zebrafish

作者：Ke Feng, Xuefan Cui, Yanlong Song, Binbin Tao, Ji Chen, Jing Wang, Shaojun Liu, Yonghua Sun, Zuoyan Zhu, Vance L. Trudeau, Wei Hu · 发表于：Endocrinology · 年份：2019 · DOI：10.1210/endocr/bqz024 · 被引用次数：53 · 研究领域：Genetic and Clinical Aspects of Sex Determination and Chromosomal Abnormalities、Reproductive biology and impacts on aquatic species、Animal Genetics and Reproduction

Gonadotropin-releasing hormone (Gnrh) plays important roles in reproduction by stimulating luteinizing hormone release, and subsequently ovulation and sperm release, ultimately controlling reproduction in many species. Here we report on a new role for this decapeptide. Surprisingly, Gnrh3-null zebrafish generated by CRISPR/Cas9 exhibited a male-biased sex ratio. After the dome stage, the number of primordial germ cells (PGCs) in gnrh3-/- fish was lower than that in wild-type, an effect that was partially rescued by gnrh3 overexpression. A terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) analysis revealed no detectable apoptosis of PGCs in gnrh3-/- embryos. Proliferating PGCs could be detected in wild-type embryos, while there was no detectable signal in gnrh3-/- embryos. Compared with wild type, the phosphorylation of AKT was not significantly different in gnrh3-/- embryos, but the phosphorylation of ERK1/2 decreased significantly. Treatment with a Gnrh analog (Alarelin) induced ERK1/2 phosphorylation and increased PGC numbers in both wild-type and gnrh3-/- embryos, and this was blocked by the MEK inhibitor PD0325901. The relative expression of sox9a, amh, and cyp11b were significantly upregulated, while cyp19a1a was significantly downregulated at 18 days post-fertilization in gnrh3-/- zebrafish. Taken together, these results indicate that Gnrh3 plays an important role in early sex differentiation by regulating the proliferation of PGCs through a MAPK-depe...