Studies On Sex-differential Expression Genes Of Schistosoma Japonicum (Chinese Strain)

Schistosomiasis is an important helminthic disease of human being and animals in the world. The pairing between male and female is necessary for the development, maturing and egg production of schistosome, and the eggs laid by the mature female parasite is the main pathogenic source for the disease. Focusing in the schistosoma japonicum (Chinese strain) spreading in China, the study on the sex-specific expressing genes "is important in theorical and practical significance for elucidating the schistosome mechanism of development and reproduction, developing novel vaccines and drugs against schistosomiasis.2-DE and mass spectrometry methods were employed to identity sex-differencial expression proteins, the peptide mass fingerprintings of two male-specific proteins and one female-specific protein of schistosome were got, and these proteins were initially analyzed by bioinformatics. The results provided basic knowladge for the following studies.RT-PCR and 5'RACE techniques were used to clone the SjGCP gene (GenBank accerssion number: AF519183) encoding gynecophoral canal protein of Schistosoma japonicum (Chinese strain). Homology analysis indicated that the protein is identical to some factors with developmental-regulated functioa It was found that the fusion protein has good antigenicity by Western-blot. Comparison with peptide of the conservative region rSjGCPl, rSjGCP induced relatively high protective effect, especially on greatly reducing the egg number in liver.The research on eggshell protein is helpful to elucidate the mechanism of female development and the development of new drugs or vaccines against egg development. In this study, RT-PCR, 5'RACE and 3'RACE techniques were used to clone the full-length cDNA of the precursor eggshell protein gene (sj423, GenBank accerssion number: AF519182). Homology analysis indicated that the protein is identical to the eggshell precursor protein of F. hepatica. Sequencing analysis showed that the gene, like that of other eggshell protein of schistosoma, has no introns. Western blotting showed that the recombinant protein had good antigenicity.Southern blotting and Northern blotting detected the sex-specific and stage-differential expression of sjGCP and sj423. The results showed that the SjGcp is a male-specific expressing gene and the gene was found to be transcripted on day 14 post infection; the Sj423 is a female-specific expressing gene and the gene was found to be transcripted on day 11 post infection. The results also showed the complexity and diversity of schistosome development, reproduction and regulated machinism.In addition, it is reported that specific IgE could play an important role in the immunological response against schistosome. The gene Sjc21.7 (GenBank accerssion number: AF519184) corresponding to Sjp21.7 (Philippines strain) that immunoscreened by IgE antibodies from high-IgE/SWAP responders was cloned. Homology analysis suggested that the protein could have the structure and function similar to tegumental protein of schistosome and calcuim-binding protein of F. hepatica. The prediction results of construction and function domains indicated that the protein has good potentiality as novel viccine against Schistosomiasis. Western blotting showed that the recombinant protein had good antigenicity.In conclusion, the expression difference of protein between male and female of Schistosoma japonicum (Chinese strain) was analyzed by 2-DE, MS and bioinformatics techniques. The male-specific gene SfGcp, female-specific gene Sj423 and important immunologic antigen gene Sfc2L7 of Schistosoma japonicum (Chinese strain) were cloned. The studies on their antigenicity, the sex-specific and stage-differential ofsjGCP and sj423 and the protective effect of rSjGcp were studied. This study provides an important foundation in theory and practice for further studying on the mechanism of sex maturing, as well as the development of novel viccines or new drugs against Schistosomiasis.