A Pilot Study Of TAP2 Gene Polymorphism In Immuno-mediated Kidney Disease

Baekgroud:TAP2, transpoter associated with antigen processing, with TAP 1 make up of thecomplex of TAP, invovled in the processing of antigentic peptide from endogenousproteins hydrolyzed by proteasomes in the cytosol loaded on the MHC I molecule ofon the cell surface to the Cytotoxic T leukomonocyte, marked variation of TAP2 leadto significance decrease of expression ofMHC Imolecule, and TAP is the centerofthe antigen processing. INF-r and IL-10 regulate the expression of TAP2. TAP2 andTAP 1 are polymorphic in all species examined. A number of studies demonstratedTAP associated with viral infection, genetic diseases, autoimmune disease andtransplantation, tumor develepment; the transporter 2 belongs to ATP-binding cassette, sub-family B gene. Moreover, as TAP2 protein comes in direct contact with antigenicpeptides, the possibility exists that its coding polymorphisms confer antigen selectivi-ty that complements that of the HLA molecules. This is consistent with an ap parentexcess of non-synonymous SNPs (four high-frequency nsSNPs, including Gly687Terthat creates a stop codon truncating the carboxyl terminal by 17 amino acids). LikeHLA, overabundance of coding TAP2 polymorphisms may reflect strong recent posi-tive selection favoring heterozygosity and specificity for emerging pathogens. In therat, strong effects on peptide selectivity by coding TAP2 polymorphisms between str-ains have indeed been unequivocally demonstrated. Although a similar effect by hu-man polymorphisms has been claimed, two thorough studies failed to find any evide-nce of it, A recent study showed that the TAP2 gene expression is influenced by gene-tic polymorphism through a mechanism involving alternative splicing of the gene.now there is no report about the study of The correlative initial study of functional mutation of TAP2 and immun-mediated disease of kidney from internal and oversea.Objective:Our study aims to investigate the genetic association between the TAP2 genepolymorphism and imrnuno-mediated kidney disease. Additional, we investigated thegenetic regulation of the TAP2 gene expression in fresh peripheral blood cells.Method:1,To collect 54 pateints of autoimmuno nephrosis, the control is the allelefrequency of rs241441 of 45 Han Chinese healthy individuals was acquiredfrom the TaqMan(?) SNP Genotyping Assays database.2,To collect the pateints' kidney biopsy result and 5 ml peripheral blood(PB).3,To abstract the DNA and RNA of PB.4,the synonymous G/A SNP at 604 Gly (rs241441) as the genetic marker, toadopt PCR technique to analyze every pateint' the genotype of TAP2rs241441.5,To investigate the genetic effect of DNA polymorphism on the mRNA levelof the transcript NM₀00544, the allelic ratio was assayed in all theheterozygous samples by RT-PCR reaction followed by re-sequencing.6,Statistics: As a pilot study for genetic association, a case-control approachwas adapted in our study. The Hardy-Weinberg equilibrium was tested in thecase group. The allele frequency was compared between the case group andthe control group by x² test.7,To analyze clinical data.Results:By x² test [x²=11.78 (p=0.0006＜0.05)] comparing TAP2 allele frequency ofrs241441 of 54 pateints of autoimmuno nephrosis and 45 Han Chinese healthyindividuals was acquired from the TaqMan(?) SNP Genotyping Assays databaseindicate there is Hardy-Weinberg disequilibrium; 54 DNA samples were successfully genotyped. Among the 54 individuals, 10 have the C/C genotype, 12 have the C/Tgenotype, and 32 have the T/T genotype.comparing to 45 Han Chinese healthyindividuals was acquired from the TaqMan(?) SNP Genotyping Assays database by x²test, x²=1.39 (p=0.2382＞0.05), there is no statistical significance, but Shown by ourstudy, there is the trend that the C allele frequency increased in the case group; For thegenetic regulation of the isoform NM 000544 mRNA level, 8 RNA samples wereassayed. Among these 8 samples, 5 samples have AT＞GC expression pattern; 2samples have AT=GC expression pattern; and 1 sample has AT000544 mRNA level may be tissue specific.