Beta-Hydroxysteroid Dehydrogenase Genes in Orange-Spotted Grouper (Epinephelus coioides): Genome-Wide Identification and Expression Analysis During Sex Reversal.

Mi Zhao,Dengdong Wang,Ling Xiao,Shuisheng Li,Yong Zhang,Yin Guo,Xin Hou,Haoran Lin

doi:10.3389/fgene.2020.00161

Abstract

Beta-hydroxysteroid dehydrogenases (β-HSDs) are a group of steroidogenic enzymes that are involved in steroid biosynthesis and metabolism, and play a crucial role in mammalian physiology and development, including sex determination and differentiation. In the present study, a genome-wide analysis identified the numbers of β-hsd genes in orange-spotted grouper (Epinephelus coioides) (19), human (Homo sapiens) (22), mouse (Mus musculus) (24), chicken (Gallus gallus) (16), xenopus (Xenopus tropicalis) (24), coelacanth (Latimeria chalumnae) (17), spotted gar (Lepisosteus oculatus) (14), zebrafish (Danio rerio) (19), fugu (Takifugu rubripes) (19), tilapia (Oreochromis niloticus) (19), medaka (Oryzias latipes) (19), stickleback (Gasterosteus aculeatus) (17) and common carp (Cyprinus carpio) (27) samples. A comparative analysis revealed that the number of β-hsd genes in teleost fish was no greater than in tetrapods due to gene loss followed by a teleost-specific whole-genome duplication event. Based on transcriptome data from grouper brain and gonad samples during sex reversal, six β-hsd genes had relatively high expression levels in the brain, indicating that these genes may be required for neurogenesis or the maintenance of specific biological processes in the brain. In the gonad, two and eight β-hsd genes were up- and downregulated, respectively, indicating their important roles in sex reversal. Our results demonstrated that β-hsd genes may be involved in the sex reversal of grouper by regulating the synthesis and metabolism of sex steroid hormones.

Highlights

IntroductionSex determination and differentiation are important processes for the continuation of species (Kobayashi et al., 2013)
In almost all vertebrates, sexual reproduction requires both females and males to maintain survival and variation.sex determination and differentiation are important processes for the continuation of species (Kobayashi et al., 2013)
The gene and protein IDs of the β-hsd genes of all species are listed in the attached table (Supplementary Table S1)

Summary

Introduction

Sex determination and differentiation are important processes for the continuation of species (Kobayashi et al., 2013). The gonads of most groupers develop into ovaries during the first sex differentiation; the ovaries of some individuals change to testis after female sexual maturation is complete in a process known as sex reversal (Liu and de Mitcheson, 2009). The synthesis of sex steroid hormones is carried out under the catalysis of a series of enzymes, and the genes encoding these enzymes include hsd3b1, hsd11b2, hsd17b1, hsd17b3, and hsd20b2 of the beta-hydroxysteroid dehydrogenases (β-HSDs) superfamily, and cyp11a1, cyp11b, cyp17a1, cyp19a1a, and cyp21a1 of the cytochrome P450 (cP450) superfamily (Tokarz et al, 2015)

Methods

Results

Discussion

Conclusion