ZFIN ID: ZDB-PUB-141115-3
Genetic Analysis of Zebrafish Gonadotropin (FSH and LH) Functions by TALEN-mediated Gene Disruption
Zhang, Z., Zhu, B., Ge, W.
Date: 2015
Source: Molecular endocrinology (Baltimore, Md.)   29(1): 76-98 (Journal)
Registered Authors: Ge, Wei, Zhang, Zhiwei, Zhu, Bo
Keywords: none
MeSH Terms:
  • Animals
  • Animals, Genetically Modified
  • Clustered Regularly Interspaced Short Palindromic Repeats
  • Female
  • Follicle Stimulating Hormone/genetics*
  • Gene Knockout Techniques
  • Luteinizing Hormone, beta Subunit/genetics*
  • Male
  • Ovary/growth & development*
  • Pituitary Gland/metabolism
  • Puberty, Delayed/genetics*
  • Spermatogenesis/physiology
  • Testis/growth & development*
  • Zebrafish/embryology
  • Zebrafish/genetics
  • Zebrafish Proteins/genetics
PubMed: 25396299 Full text @ Mol. Endocrinol.
Vertebrate reproduction is controlled by two gonadotropins (FSH and LH) from the pituitary. Despite numerous studies on FSH and LH in fish species, their functions in reproduction still remain poorly defined. This is partly due to the lack of powerful genetic approaches for functional studies in adult fish. This situation is now changing with the emergence of genome-editing technologies, especially TALEN and CRISPR/Cas9. In this study, we deleted the hormone-specific β genes of both FSH and LH in the zebrafish using TALEN. This was followed by phenotype analysis for key reproductive events, including gonadal differentiation, puberty onset, gametogenesis, final maturation, and fertility. FSH-deficient zebrafish (fshb(-/-)) were surprisingly fertile in both sexes; however, the development of both ovary and testis was significantly delayed. In contrast, LH-deficient zebrafish (lhb(-/-)) showed normal gonadal growth, but the females failed to spawn and were therefore infertile. Using previtellogenic (PV) follicles as the marker, we observed a significant delay of puberty onset in fshb mutant but not lhb mutant females. Interestingly, FSH seemed to play a role in maintaining female status as we repeatedly observed sexual reversal in fshb mutant. Neither fshb nor lhb mutation alone seemed to affect gonadal differentiation; however, double mutation of the two genes led to all males although the development of the testis was significantly delayed. In summary, our data confirmed some well-known functions of FSH and LH in fish while also providing evidence for novel functions, which would be difficult to reveal using traditional biochemical and physiological approaches.