Résumé
AIM: To observe the effect of LPS on CIAS1 gene expression and to analyze the function-structure relationship of its mutation region, the NACHT domain of cryopyrin. METHODS: RT-PCR was used to detect the expression of CIAS1 gene in human leucocytes in the presence of LPS. The methods of molecular modeling and bioinformatics were used to observe the relationship of the structure-function of NACHT domain in human CIAS1 gene. RESULTS: LPS increased CIAS1 mRNA expression in a dose-dependent manner. However, the stimulation with LPS at a concentration of 100 mg/L at different time points showed the pattern of early down-regulation and later up-regulation of CIAS1 mRNA expression. The sequence analysis suggested that the motifs Walker A and Walker B, to which the ATP and Mg~ 2+ can bind, were found in the NACHT domaim of CIAS1 gene encoded product cryopyrin. The main points of the disease-associated mutation showed the close relation in sequence and structure to these motifs. The binding sites of Ca~ 2+ and polysaccharide were observed in the leucine rich repeats region of cryopyrin. CONCLUSION: Cryopyrin may act as an important regulator in inflammation. LPS induces human leukocytes to express the CIAS1 gene product.