Molecular Clone Of Biotransformation Genes And Analysis Of Their Expression In Rare Minnow Gobiocypris Rarus

It is well known that endocrine disrupting chemicals(EDCs) can interfere with the hormonal system of wild animal and human. Bisphenol A(BPA) and 17α-methyltestosterone(MT) were two EDCs that widely used in the production and life. They would eventually immerge into water, damaged the reproductive system and endocrine system of aquatic species. To date, the metabolic pathway of EDCs in vivo is still an uncharted territory. Aiming to evaluate the effects of EDCs on genes involved in biotransformation pathway and to unravel their metabolic pathway at the transcriptional level in fish, we firstly isolated cDNAs of rare minnow PXR, AHR2, Sult1 st1, Sult1 st4, Sult1 st6, Ugt2a1 and Ugt2b6, then investigated tissue distributions of AHR2, PXR, Cyp1 a, Cyp3 a, Sult1 st1, Sult1 st4 and Sult1 st6 in adult rare minnow. Last but not least, we detected expression patterns of PXR, Cyp3 a, Sult1 st4 and Sult1 st6 upon 14- and 35-day BPA(5, 15 and 50 μg/L) exposure and expression patterns of PXR, AHR2, Cyp1 a, Cyp3 a, Sult1 st1, Sult1 st4, Sult1 st6, Ugt2a1 and Ugt2b6 upon 7-, 14- and 21-day MT(25, 50 and 100 ng/L) exposure in the liver of adult rare minnow in the present study.The main results of the present study are as follows.1. The full-length cDNAs of PXR, Sult1 st1, Sult1 st4 and Sult1 st6 are 1745 bp, 1494 bp, 1441 bp and 1439 bp, respectively. Their corresponding deduced amino acid numbers were 434, 301, 301 and 307. The homology and phylogenetic analyses of the amino acid sequences confirmed that there were high identities between these biotransformation genes of G. rarus and other cyprinid fish.2. The biontransformation genes are all mainly expressed in liver in both sexes of adult G. rarus. PXR is moderately expressed in muscle and gonad, AHR2 is a widespread gene that moderately expressed in brain in both sexes of adult G. rarus. Cyp1 a, Cyp3 a, Sult1 st1 and Sult1 st6 are moderately expressed in intestine. Ugt2a1 is widely expressed and moderately expressed in intestine and gonad of both sexes. Moreover, Sult1 st4 is also highly expressed in brain, and Ugt2b6 is also mainly expressed in intestine in both genders of adult G. rarus.3. In response to BPA, sexual dimorphism of expression patterns for PXR, Cyp3 a and Sult1 st6 shows in G. rarus, which includes increase of mRNA levels in females and decrease of mRNA levels in males in both exposure durations of 14 and 35 days. Sult1 st6 mRNA demonstrates high responsiveness to BPA in both genders and we recommended Sult1 st6 as a candidate biomarker for BPA exposure.4. Upon MT exposure, sexually dimorphic in hepatic transcripts of Cyp1 a was found in adult rare minnow. The present findings suggest that AHR2 and PXR should play important roles in regulating biotransformation enzymes related to MT catabolism, moreover, CYP1 A, CYP3 A, SULT1 ST4, SULT1 ST6 and UGT2A1 may play certain roles in catabolism of MT in adult G. rarus. Additionally, UGT2A1 may make greater contribution than SULT1 ST4 and SULT1 ST6 in MT catabolism in males.In summary, this study explored the transcription from EDCs possible biological transformation process in adult G. rarus. This study is the basis of the eliminate metabolism of exogenous substances, and is important both in theory and in practice of its matting role for future studies.