Molecular cloning, characterization and expression pattern of androgen receptor in Spinibarbus denticulatus

Androgens play key roles in sex differentiation, gonadal maturation and reproductive behaviors and their actions are generally mediated through androgen receptor (AR). In the present study, isolation, sequencing and characterization of cDNA encoding AR and its temporal and spatial expression profiles in both sexes of Spinibarbus denticulate were carried out. Androgen receptor of Spinibarbus denticulate (sdAR) was 3172bp in length and encoded a 95.4kDa protein of 865 amino acids. Phylogenetic analysis and multiple amino acids sequence alignment indicated the close relationship and high score similarity of sdAR with ARs of other cyprinid species. A single transcript of approximate 3.2kb was identified in testis, liver and brain. RT-PCR assay characterized that sdAR mRNA was broadly distributed in both central nervous system (CNS) and most of peripheral tissues in male fish, while was confined to olfactory, telencephalon and hypothalamus of CNS and peripheral tissues including liver, spleen, head kidney, heart, and red muscle in females. During the embryonic development, sdAR mRNA was firstly detected at 16-cells stage and mid blastula stage with very weak signal. Little or no signal was detected in mid gastrula and neurula stages. The expression was occurred in the following developmental phases as well as in larvae of 4 days post hatching. During gonadal recrudescence process, liver of both sexes and testis were the most AR mRNA abundant tissues. In male fish, abundance of sdAR mRNA significantly varied in pituitary at fully recrudesced stage and brain at late recrudescing phase, respectively. No significant variation was found throughout the ovary recrudesce in each tissue checked. Our present work provided preliminary evidences that AR mediated androgen action on reproduction and development in both sexes of S. denticulate.