Journal Article

Histological and transcriptomic effects of 17α-methyltestosterone on zebrafish gonad development

Fisher, Amanda, Horsfield, Julia A., Black, Michael A., Gemmell, Neil J., Lee, Stephanie Ling Jie, Rutherford, Kim

2017

Overview

Background Sex hormones play important roles in teleost ovarian and testicular development. In zebrafish, ovarian differentiation appears to be dictated by an oocyte-derived signal via Cyp19a1a aromatase-mediated estrogen production. Androgens and aromatase inhibitors can induce female-to-male sex reversal, however, the mechanisms underlying gonadal masculinisation are poorly understood. We used histological analyses together with RNA sequencing to characterise zebrafish gonadal transcriptomes and investigate the effects of 17α-methyltestosterone on gonadal differentiation. Results At a morphological level, 17α-methyltestosterone (MT) masculinised gonads and accelerated spermatogenesis, and these changes were paralleled in masculinisation and de-feminisation of gonadal transcriptomes. MT treatment upregulated expression of genes involved in male sex determination and differentiation ( amh , dmrt1 , gsdf and wt1a ) and those involved in 11-oxygenated androgen production ( cyp11c1 and hsd11b2 ). It also repressed expression of ovarian development and folliculogenesis genes ( bmp15 , gdf9 , figla , zp2.1 and zp3b ). Furthermore, MT treatment altered epigenetic modification of histones in zebrafish gonads. Contrary to expectations, higher levels of cyp19a1a or foxl2 expression in control ovaries compared to MT-treated testes and control testes were not statistically significant during early gonad development (40 dpf). Conclusion Our study suggests that both androgen production and aromatase inhibition are important for androgen-induced gonadal masculinisation and natural testicular differentiation in zebrafish.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Analysis / Androgens / Animal Genetics and Genomics / Animals / Aromatase / Biomedical and Life Sciences / Danio rerio / Differentiation / Domestication / Estrogens / Ethanol / Female / Females / Folliculogenesis / Gametocytes / Gene expression / Gene sequencing / Genes / Genetic aspects / Genomics / Gonad differentiation / Gonads / Histones / Hormones / Hypotheses / Laboratory animals / Life Sciences / Male / Methyltestosterone / Methyltestosterone - pharmacology / Microarrays / Microbial Genetics and Genomics / Non-human and non-rodent vertebrate genomics / Ovaries / Ovary - cytology / Ovary - drug effects / Ovary - growth & development / Ovary - metabolism / Physiological aspects / Plant Genetics and Genomics / Proteomics / Research Article / Ribonucleic acid / RNA / RNA sequencing / Sex Characteristics / Sex determination / Sex differentiation / Sex hormones / Sex Ratio / Sex reversal / Solvents / Spermatogenesis / Spermatogenesis - drug effects / Spermatogenesis - genetics / Statistical analysis / Studies / Testes / Testis - cytology / Testis - drug effects / Testis - growth & development / Testis - metabolism / Tilapia / Transcriptome - drug effects / Zebra fish / Zebrafish / Zebrafish - genetics / Zebrafish - growth & development