The Expression Study Of Cathepsin B Gene In Ovary Development Of Marsupenaeus Japonicus

Penaeid shrimp Marsupenaeus japonicas is important economic cultivation species in the southeast China.We have cloned the full-length cDNA of Cathepsin B.The expression of Cathepsin B is high in ovary of M.Japonicas,which is hardly detected in testis.The expression of Cathepsin B in ovary development is studied by real-time PCR,immunohistochemistry(IHC),Western blot,in situ hybridization(ISH)and so on.The four stages of ovary development is determined according to hematoxylin eosin stain(HE)and gonad-somatic index(GSI),including previtellogenic stage(PR),endogenous vitellogenic stage(EN),exogenous vitellogenic stage(EX)and mature stage(MA).The expression of Cathepsin B is tested in the different ovary development stages by real-time PCR.The results show Cathepsin B is in the highest level in PR,medium level in EN and EX.However the expression suddenly declines and is in the lowest level in MA.Cathepsin B of PR has significant difference compared with that of EN,EX and MA respectively(p<0.05).There is no significant difference between EN and EX stages(p>0.05).The expression of Cathepsin B in MA is significantly different from that in other three stages(p<0.05).Cathepsin B protein is in the lowest in PR by Western blot,which does not coincide with mRNA from Real-time PCR.It is inferred that the control mechanism of Cathepsin B may be a post-transcription.The molecular weight of Cathepsin B protein in Western blot is larger than that from theory.We deduce Cathepsin B is a post-translational regulation protein.The decrease of mRNA and protein of Cathepsin B in MA implies the effect of Cathepsin B may decline in the stage.Both mRNA and protein are expressed in cytoplasm according the results of ISH and IHC.We notice Cathepsin B protein firstly appear in the position close to nucleus by IHC.But the Cathepsin B protein and mRNA are not detected in cortical rods in MA.The results from above study indicates Cathepsin B play an important role in the ovarian development of the M.Japonicas.