[Cloning of full-length cDNA of HMGR from Gobiocypris rarus and analysis of its expression profiles in male exposed to pentachlorophenol].

3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) is the first rate-limiting enzyme in the mevalonate (MVA) pathway. The full-length cDNA of HMGR was cloned from Gobiocypris rarus, and HMGR expression profiles in different tissues and in response to different treatments of pentachlorophenol (PCP) were analyzed by real-time PCR, to investigate the endocrine disruption mechanism of PCP, which altered steroid hormone precursors (cholesterol) levels by modulating gene transcription profiles of HMGR. Based on the homologous clone strategy and rapid-amplification of cDNA ends (RACE) technology, the full-length 3 101-base-pair (bp) cDNA of HMGR was isolated from the livers of rare minnow (Gobiocypris rarus) for the first time, and was designated as GrHMGR (GenBank accession number KF885724). GrHMGR encoded a protein of 884 amino acids and phylogenetic tree analysis indicated that the deduced protein GrHMGR had extensive sequence similarities to other fish HMGRs. Real-time PCR analyses indicated that GrHMGR mRNA expression was tightly controlled in a tissue-specific fashion, with the sites of expression being brain, gonads and liver, and the highest site of expression being gonads. After male rare minnows were exposed to different concentrations of PCP, significant decrease in GrHMGR gene expression with increased PCP concentration in the brain and gonads were observed, together with the differential gene expression trend in the liver. Furthermore, it was found that the decrease of HMGR could reduce the synthesis of cholesterol. This proved that PCP might disrupt the pathway of cholesterol synthesis and then influenced the endocrine system of rare minnow.