Gnrh3 regulates PGC proliferation and sex differentiation in developing zebrafish

Feng, K., Cui, X., Song, Y., Tao, B., Chen, J., Wang, J., Liu, S., Sun, Y., Zhu, Z., Trudeau, V.L., Hu, W.
Endocrinology   161(1): (Journal)
Registered Authors
Hu, Wei, Sun, Yonghua, Trudeau, V.L., Zhu, Zuoyan
Gnrh3, PGC proliferation, gene knockout, reproduction, sex differentiation, zebrafish
MeSH Terms
  • Animals
  • Benzamides/pharmacology
  • Diphenylamine/analogs & derivatives
  • Diphenylamine/pharmacology
  • Embryo, Nonmammalian/cytology
  • Embryonic Stem Cells/drug effects
  • Embryonic Stem Cells/physiology*
  • Gene Deletion
  • Gene Expression Regulation, Developmental/drug effects*
  • Gene Expression Regulation, Developmental/physiology
  • Gonadotropin-Releasing Hormone/analogs & derivatives
  • Gonadotropin-Releasing Hormone/genetics
  • Gonadotropin-Releasing Hormone/metabolism*
  • Gonadotropin-Releasing Hormone/pharmacology
  • MAP Kinase Signaling System/physiology
  • Male
  • Phosphorylation
  • Proto-Oncogene Proteins c-akt/genetics
  • Proto-Oncogene Proteins c-akt/metabolism
  • Pyrrolidonecarboxylic Acid/analogs & derivatives*
  • Pyrrolidonecarboxylic Acid/metabolism
  • Sex Differentiation/physiology*
  • Sex Ratio
  • Zebrafish/embryology*
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
31758175 Full text @ Endocrinology
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 was generated by CRISPR/Cas9 and exhibited a male-biased sex ratio. After the dome stage, the number of primordial germ cells (PGCs) in gnrh3-/- fish was less than that in wild-type, an effect that was partially rescued by gnrh3 overexpression. A 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 to 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 up-regulated, while cyp19a1a was significantly down-regulated 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-dependent path.
Genes / Markers
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Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Engineered Foreign Genes