Cloning and expression of Sj423 gene encoding the egg-shell precursor protein of Schistosoma japonicum / 中国人兽共患病学报

ABSTRACT

The gene fragment encoding the egg-shell precursor protein of Schistosoma japonicum was amplified with RT-PCR by using PCR primer designed according to the 423 bp cDNA fragment of the Philippine strain of S.japonicum, the corresponding mDNA fragment of Chinese strain as template and then the 5' and 3' ends of this gene cDNA were amplified with 5' RACE and 3' RACE by using a series of primers designed according to the result of sequencing. Result of sequence analysis showed that this fragment, named as Sj423, contained a complete open reading frame (ORF) of gene encoding the egg-shell precursor protein of S.japonicum.(Chinese strain). As demonstrated by sequencing analysis. No intron could be detected in this gene fragment. This gene was subsequently expressed in E.coli after cloning into the expression vector pET28c(+). The molecular mass of the expressed product of this gene was 20.9 kDa as revealed by SDS-PAGE analysis, and Western blot analysis showed that the recombinant protein expressed could react well with the rabbit antiserum against the worm antigen of S.japonicum;indicating the good antigenicity of this expressed product.