Cloning And Expression Analysis Of β-catenin2 Gene In Common Carp(Cyprinus Carpio)

β-catenin genes,a key factor of the Wnt/β-catenin signaling pathway,which is rare in the studies of gonadal development and differentiation in fish.In this study,we firstly cloned and got the full-length cDNA sequence of β-catenin2 gene(GeneBank:MF491393)from the FFRC strain common carp,and investigated the expression characteristics of β-catenin2 in the development of gonad and its expression patterns in various tissues,as well as the expression characteristics of β-catenin2 in the gonad after sex hormone treatment.The main results are as follows:1.The full-length cloning of the β-catenin2 cDNA of FFRC CyprinuscarpioA 3411 bp full-length cDNA of β-catenin2 was obtained by the SMARTer RACE 5’/3’ rapid cloning technique,with a 2343 bp open reading frame(ORF),and encoded 780 amino acids;the predicted protein size was 85.52 kDa and the isoelectric point(pI)was 5.53.Bioinformatics analysis showed that the central region of β-catenin2 contains 12 Armadillo(ARM).The protein encoded by the β-catenin2 gene contains the N-terminal domain of lipoproteins.This domain was found in lipid transporters,such as vitellogenin,microsomal triglyceride transporters,and apolipoproteins.In addition,this domain was highly conserved both in vertebrates and invertebrates.2.The expression patterns of β-catenin2 gene in during different stage of gonadal development and in various tissues of FFRC CyprinuscarpioReal-time PCR showed that the expression pattern of the β-catenin2 mRNA in different stage of the gonadal development was as follows:In the testis,the expression level of β-catenin2 mRNA was at the lowest level in its mature stage(T1),and at medium level in its developmental recession period(T2)and early stage of development(T3),and eventually reached the highest level in the middle stage of its development(T4).In the ovary,the expression level of β-catenin2 mRNA was at the lowest level in the complete maturation(O1)and decline(02)of itsdevelopment,at the medium level in the early stages(03),and at the highest level in the medium stage(O4).The expression patterns of β-catenin2 mRNA in the tissues of common carp were as follows:the highest expression level of β-catenin2 genes was the blood,following by the testis,ovary,and spleen,while with the lower expression levels in the heart,muscle,brain,skin,kidney,intestine,and liver.3.The expression level of the β-catenin2 mRNA in the gonad of FFRC Cyprinuscarpio after sex hormone treatmentThe FFRC Cyprinuscarpio were injected with sex hormones at the concentrations of 0,1,10,and 50 μg/g,respectively,and their gonadal tissues were sampled at 24,48,and 72 h after treatment.The expression levels of β-catenin2 mRNA in the gonads of FFRC Cyprinuscarpio were detected by RT-PCR.After treatment with testosterone(T),the level of β-catenin2 mRNA in ovary was significantly increased at the concentration of 10 μg/g and sample time of 24 h<0.05),while the level of β-catenin2 mRNA in testis at the concentration of 10 μg/g and 50 μg/g and sample time of 48 h were significantly reduced(P<0.05).After treatment with 17-β-Ethinylestradiol(E2),there were no significantly changes in the levels of β-catenin2 mRNA both in the testis(P>0.05),and The expression levels ofβ-catenin2 mRNA in ovary significantly reduced was at 1μg/g 24 h、48 h and 50 μg/g 48 h(P<0.05)..,while the expression levels of β-catenin2 mRNA in ovary significantly increased at 10 μg/g 72 h(P<0.05).All of the above results suggest thatβ-catenin2 gene maybe involves in the early gonadal development of common carp.