| The transporter associated with antigen processing(TAP) belongs to the superfamily of ATP-binding cassette(ABC) transporter. TAP is the key players in MHC class I molecules function, MHC-I molecules play a major role in the immune response against viral infections and transformed cells by presenting peptide antigens to cytotoxic T lymphocytes(CTL).When TAP dysfunction or decreased expression will lead to tumor antigens can not be efficiently transported, resulting in tumor escape from immune surveillance. It is that recognition of the role of TAP gene in human and mammalian diseases which more than in poultry.Marek's disease(MD) is a devastating oncogenic viral disease of chickens caused by Gallid herpesvirus 2, or MD virus(MDV). MD caused significant economic losses in the poultry industry of different centuries worldwide. And MDV virulence constantly increasing,vaccination can't effectively prevented and control, so we should use same genetic technology to testing, pointedly treatment and prevention MD. The purpose of this study was to research the association study of gene variations of TAP in Jining hundred days,Shouguang and SPF chickens with Marek's disease.The study of the correlation of TAP gene polymorphism between the MD, which againsted Jining hundred days chickens, Shouguang chickens, SPF chickens, by the molecular markers technology, statistics the correlation of the different genotypes with MD, results found TAP1-3, TAP1-4, TAP2-2 and TAP2-3 primer amplification products have polymorphic genotypes. Second, further on laboratory toxicity test on the three varieties of chicken,statistics the variation locuses of TAP specific fragment, we could find that the variation locuses of TAP specific fragment had 18, 14, 16 gene variations loci in Jining hundred days chickens, Shouguang chickens, SPF chickens, respectively, in Jining hundred days chickens,Shouguang chickens, SPF chickens were found 12, 14, 13 gene variations loci in TAP2 specific. Statistics on gene variations loci, we found that there were four variation locuses sites of TAP1 leaded to amino acid changes, there were 7 variation locuses of TAP2 leaded to amino acid changes. Correlation studies of variation locuses with Marek's disease, found that the gene coding region of TAP had 24 variation locuses, of which there were JB1323, JB1050,JB1148, SG1303, SPF1082 and SPF1196 site, they were correlated with the susceptibility of marek's disease(P<0.05). To further known six variation locuses by different genotype genetic model analysis, found JB1323 and JB1050 was susceptible to high-risk gene loci of marek's disease, JB1323(C?T) site could change from alanine to valine, JB1050 points(G?T)could turn alanine into serine.To further understand the correlation of TAP expression with MD, the study by fluorescence quantitative PCR method to study changes in the expression of TAP, which in different genotypes individuals in JB1323 and JB1050 loci, we could find the expression of TAP which in susceptibility homozygote was lower than that of wild homozygote in JB1323 loci, the expression of TAP which in heterozygote was lower than that of homozygote in JB1050 loci, but no significant difference(P>0.05). Marek's disease virus infection TAP1 expression was significantly increased in heart, liver, significantly decreased expression in spleen, and the expression of TAP1 did not change significantly in kidney and lung. Detection of TAP2 expression was found the TAP2 of disease group was significantly decreased in the spleen. Further analysis of chicken spleen TAP expression levels was found that the expression of TAP was increase in the earlier infection of MDV, then decline, which indicated that TAP express quantity to rise flag the early of MDV infection, for the detection of Marek's disease. |
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