PUBLICATION

Identification of sex differences in zebrafish (Danio rerio) brains during early sexual differentiation and masculinisation using 17α-methyltestoterone

Authors
Lee, S.L.J., Horsfield, J.A., Black, M.A., Rutherford, K., Gemmell, N.J.
ID
ZDB-PUB-171223-6
Date
2017
Source
Biology of reproduction   99(2): 446-460 (Journal)
Registered Authors
Horsfield, Jules, Lee, Stephanie Ling Jie
Keywords
Zebrafish, androgens, neuroendocrinology, reproductive behaviour, sex differentiation
MeSH Terms
  • Alcohol Oxidoreductases/genetics
  • Alcohol Oxidoreductases/metabolism
  • Animals
  • Aromatase/genetics
  • Aromatase/metabolism
  • Brain/drug effects
  • Brain/metabolism*
  • Female
  • Gene Expression*
  • Male
  • Methyltestosterone/pharmacology*
  • Prostaglandin-Endoperoxide Synthases/genetics
  • Prostaglandin-Endoperoxide Synthases/metabolism
  • Sex Characteristics*
  • Sex Differentiation/physiology*
  • Sexual Behavior, Animal/drug effects
  • Sexual Behavior, Animal/physiology*
  • Zebrafish
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
PubMed
29272338 Full text @ Biol. Reprod.
Abstract
Sexual behaviour in teleost fish is highly plastic. It can be attributed to the relatively few sex differences found in adult brain transcriptomes. Environmental and hormonal factors can influence sex-specific behaviour. Androgen treatment stimulates behavioural masculinisation. Sex dimorphic gene expression in developing teleost brains and the molecular basis for androgen-induced behavioural masculinisation are poorly understood. In this study, juvenile zebrafish (Danio rerio) were treated with 100 ng/L of 17 alpha-methyltestosterone during sexual development from 20 days post fertilisation to 40 days and 60 days post fertilisation. We compared brain gene expression patterns in MT-treated zebrafish with control males and females using RNA-Seq to shed light on the dynamic changes in brain gene expression during sexual development and how androgens affect brain gene expression leading to behaviour masculinisation. We found modest differences in gene expression between juvenile male and female zebrafish brains. Brain aromatase (cyp19a1b), prostaglandin 3a synthase (ptges3a) and prostaglandin reductase 1 (ptgr1) were among the genes with sexually dimorphic expression patterns. MT treatment significantly altered gene expression relative to both male and female brains. Fewer differences were found among MT-treated brains and male brains compared to female brains, particularly at 60 dpf. MT treatment upregulated the expression of hydroxysteroid 11-beta dehydrogenase 2 (hsd11b2), deiodinase, iodothyronine, type II (dio2), gonadotrophin releasing hormones (GnRH) 2 and 3 (gnrh2 and gnrh3) suggesting local synthesis of 11-ketotestosterone, triiodothyronine and GnRHs in zebrafish brains which are influenced by androgens. Androgen, estrogen, prostaglandin, thyroid hormone and GnRH signalling pathways likely interact to modulate teleost sexual behaviour.
Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping