The Expression Of Sox9, Cyp19 And Esr1 Genes In The Gonads Of Giant Salamanders In Different Developmental Stages

Chinese giant salamander(Andrias davidianus)is our country unique amphibians belonging to the wild animal,animal class II protected.Flourish of Chinese giant salamander breeding as a new special aquaculture industry with the development of breeding technology in recent years.Previous studies showed that during gonadal differentiation phase,Chinese giant salamander differentiate into male at high temperature,while at the same conditions Chinese giant salamander differentiate into female when exposed in appropriate concentrations of exogenous 17β-estradiol(17β-E2).2000 the juvenile salamander wasdivideded into experimental and control group randomly at the beginning of December From 2012 to 2013,the experimental group exposed in appropriate concentrations of exogenous 17β-E2 for 40 days.Anatomical and histological techniques were used for identify gonadal sex of 8,12,20,36 month-old Chinese giant salamander.Sox9,Cyp19 and Esrl which relate sex determination and gonadal differentiation in caudate amphibians,were selected to measure the expression of these genes by RT-PCR technique.It aims to explore the role and molecular mechanisms of these genes in the giant salamander sex determination and gonadal differentiation,As well as provide a basis theoretical for the sustainable and healthy development of this ancient species race and the continuation of industry.The main results and conclusions are the following:1.undifferentiated gonad to differentiate into ovary by exogenous17β-E2,and no histological abnormalities compared with the control group ovary.2.The partial cDNA sequence of Cyp19,Esrl were frist amplified in Chinese giant salamander.3.Chinese giant salamander gonads in the control group during 8,12,20,36 months-old:Sox9 mRNA expression appears to be up-regulated in different developmental stages,compared with 8,12 and 20 month-old,Sox9 mRNA expression significantly increased in 36 month-old(P<0.01);In testis,Sox9 mRNA expression firstly increased and then decreased.Besides,in different developmental stages of gonad in Chinese giant salamander,Sox9 mRNA expression in ovary is significantly higher than that in testis.Thus we speculate that Sox9 plays an important role in the synthesis of the yolk.4.Chinese giant salamander gonads in the control group during 8,12,20,36 months-old:Cyp19 mRNA expression level was gradually decreased in the ovary,Cyp19 mRNA expression level is extremely high in 8 month-old ovary(P<0.01);Cyp19 mRNA expression basically shows the trend of rising in testis;Cyp19 mRNA expression in ovary is significantly higher than that in testis(P<0.01).It is suggesting Cypl9 may play an important role in gonadal differentiation and ovarian development.5.Chinese giant salamander gonads in the control group during 8,12,20,36 months-old:The results showed that Esrl mRNA expression significantly higher in 8 month-old overy(P<0.01);Esrl mRNA expression shows the trend of rising in12,20,36 month-old.Esrl mRNA always maintain high expression level in testis;Esrl mRNA expression in ovary is significantly higher than that in testis except 8 month-old(P<0.01).It is suggested that Esrl might be invovled in the differentiation and development of the ovary;Esrl possible be invovled in oocytes development and spermatogonia formation.6.The relatively expression of Sox9,Esr1,Cyp19 mRNA in 8,12,20 month-old Chinese giant salamander ovary had no significant difference between experimental and control group.It is suggest that there is no significantly residues exogenous 17β-E2 exists in the Chinese giant salamander.