| It has been demonstrated that the variations in genomic DNA sequence, i.e. gene polymorphisms are the most important determinants for disease susceptibility, clinical phenotype diversity and different response to pharmacotherapies. Our previous researchers have demonstrated that pattern recognition receptors(PRRs) on the membrane of effector cells , such as CD14, Toll-like receptor4, MD2, the protein kinases in intracellular signal transduction pathway, pro-inflammatory cytokines(such as TNF(,IL-1(,IL-6,IL-8) and anti-inflammatory cytokines (such as IL-4,IL-10,IL-1Ra) contribute to the pathogenesis of sepsis. Therefore, the differences in the expression of inflammation-related genes should be the determinants for susceptibility to sepsis. Based on the above analysis and the current researches, the present study focused the following three aspects: (1) To thoroughly analyze the occurrence of single nucleotide polymorphisms in all of important regions of 18 inflammation-related candidate genes by large-scaled sequencing procedure in Chinese. (2) To further examine the allele frequency distributions of -1892 and -1837 positions in 5'flank region of TLR4 and their linkage relationship in Chongqingnese. (3) To investigate the possible functional significance of the remote region of 5'flank and its relationship with -1892G→A and -1837A→G base mutation with gene cloning techniques and bioinformatical methods. The purpose of this study was to provide basis for further investigation of genetic background of susceptibility to sepsis. The main results and conclusion were summarized as follows:1. Eighteen inflammation-related candidate genes were selected respectively from PRRs on the cell surface of effector cells, intracellular signal tranduction molecules, pro-inflammatory and anti-inflammatory cytokines. All of the important regions of the 18 genes such as 5'flank region, 5'UTR, intron regions adjacent to exons ,coding regions, 3'UTR and 3'flank region were sequenced for SNP analysis. Throughout the analysis of 27 samples from 10 representitive nationalities such as Mongolian,Tibetan, Weiwuer, Dai, This work was supported by the Major State Basic Research Development Program of China (No.G1999054203)Bulang, Miao, Zhuang, Li, Chaoxian and Han in China, a primary Chinese SNP database was established for inflammation-related genes.2. The allele frequency distributions of -1892 and -1837 positions in 5'flank region of TLR4 were further surveyed in Chongqingnese population. The results revealed that the -1892 and -1837 positions not only have high occurrence of base mutaion (-1892G→A ,-1837A→G ) and high heterozygosity, but also have close linkage relationship. Population subjected to base mutation at both potions accounted for 39.7%, showing the major SNP genotype is G/A-A/G heterozygote.3. The biological significance of the remote regulatory region of 5'flank of TLR4 were investigated with bioinformatical methods and gene cloning techniques. The results showed that the region in which -1837 locus located is the binding regions for several transcriptional activators, such as C/EBP,Oct-1and Oct-6. The region around -1892 locus, although could not bind any transcriptional activator, become a binding region for AP-1 when base mutation occurs at this point (G→A).It suggests that although -1892 and -1837 loci are far from the promoter, they may play a remote regulation on the target gene expression. Results from gene clone and transfection further indicated there is a region that plays an enhancement of the promoter function among -2413～-683 bp. Further experiments revealed that the enhancer-like region is located in -1336～-683 bp. It suggests that the region of -2413～-1337 bp where -1892 and -1837 loci locate may play a regulation on target gene expression through other mechanism.
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