PUBLICATION

Targeted Mutagenesis of the Hypophysiotropic Gnrh3 in Zebrafish (Danio rerio) Reveals No Effects on Reproductive Performance

Authors
Spicer, O.S., Wong, T.T., Zmora, N., Zohar, Y.
ID
ZDB-PUB-160630-4
Date
2016
Source
PLoS One   11(6): e0158141 (Journal)
Registered Authors
Zohar, Yonathan
Keywords
Zebrafish, Pituitary gland, Immunohistochemistry techniques, Immunostaining, Neurons, Polymerase chain reaction, TALENs, Gonadotropins
MeSH Terms
  • Animals
  • Cell Differentiation
  • Female
  • Gene Expression Profiling
  • Gene Expression Regulation
  • Gene Knockout Techniques
  • Gonadotropin-Releasing Hormone/genetics*
  • Gonadotropin-Releasing Hormone/physiology
  • In Situ Hybridization
  • Male
  • Mutagenesis*
  • Mutation*
  • Neurons/metabolism
  • Pyrrolidonecarboxylic Acid/analogs & derivatives*
  • RNA, Messenger/metabolism
  • Reproduction*
  • Zebrafish/embryology*
  • Zebrafish/genetics*
PubMed
27355207 Full text @ PLoS One
Abstract
Gnrh is the major neuropeptide regulator of vertebrate reproduction, triggering a cascade of events in the pituitary-gonadal axis that result in reproductive competence. Previous research in mice and humans has demonstrated that Gnrh/GNRH null mutations result in hypogonadotropic hypogonadism and infertility. The goal of this study was to eliminate gnrh3 (the hypophysiotropic Gnrh form) function in zebrafish (Danio rerio) to determine how ontogeny and reproductive performance are affected, as well as factors downstream of Gnrh3 along the reproductive axis. Using the TALEN technology, we developed a gnrh3-/- zebrafish line that harbors a 62 bp deletion in the gnrh3 gene. Our gnrh3-/- zebrafish line represents the first targeted and heritable mutation of a Gnrh isoform in any organism. Using immunohistochemistry, we verified that gnrh3-/- fish do not possess Gnrh3 peptide in any regions of the brain. However, other than changes in mRNA levels of pituitary gonadotropin genes (fshb, lhb, and cga) during early development, which are corrected by adulthood, there were no changes in ontogeny and reproduction in gnrh3-/- fish. The gnrh3-/- zebrafish are fertile, displaying normal gametogenesis and reproductive performance in males and females. Together with our previous results that Gnrh3 cell ablation causes infertility, these results indicate that a compensatory mechanism is being activated, which is probably primed early on upon Gnrh3 neuron differentiation and possibly confined to Gnrh3 neurons. Potential compensation factors and sensitive windows of time for compensation during development and puberty should be explored.
Genes / Markers
Figures
Show all Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping