Study On The Conmelation Between Single Nucleotide Polymorphism(SNP)of CD81,DL-Rand HCV Infection Susceptiblilty

Hepatitis C (HC) is caused by hepatitis C virus(HCV) ,which could lead to cirrhosis and liver cancers. Except for environment factor, the infection of different types of HCV, there exists difference of genetic susceptibility which can lead to various effects in human population. The mechanism by which HCV infects host cells remains unknown. A great deal of evidence shows that human CD81 is a first receptor of HCV infection by the binding of its extracellular loop EC2 and HCV. Low Density Lipoprotein Receptor (LDLR) is also regarded as a receptor, which conducts HCV into cells after the binding of HCV to density lipoprotein. HCV can not bind the CD81 of African Green Monkey(AGM). Four amino acids(163, 186, 188, 196) locating in EC2 of CD8I are different between human and AGM. Objective The study was conducted to investigate whether there is single nucleotide polymorphism(SNP) which has relation with the infection of HCV in CD81 gene or LDLR gene in Chinese population. Methods PCR and DNA sequencing methods were used to examine exon 6, 7, 8 of CD81 which are the correspondent sites of the EC2 and exon 2,3,4,5,6 of ligand binding region of LDLR in healthy people and patients withmHCV infection. Results (l)No SNP was found in exon 6,7,8 of CD81.Though three SNPs were found in intron 6 (11028G/T)and3downstream regulatory region (11860C/T, 11960G/A), they did not effect the primary structure of CD81 protein and had nothing to do with the susceptibility of HCV infection(P>O.05). (2) Exon 2,3,4,5,6 of LDLR gene also had no SNP, but three SNPs were found in intron 2, which also had no relation with the susceptibility of HCV infection(P>O. 05). Conclusion (1) Exon 6,7,8 have no relation with the susceptibility of HCV infection. The genetic basis of the four amino acids is highly conserved in Chinese population. Because other sites of CD81 protein are highly conserved among species, there is no or very rare polymorphism of CD8I in Chinese people. (2) The susceptibility of HCV infection has nothing to do with the genetic basis of the ligand binding region of LDLR.Postgraduate DongQiumingDirected by Professor Gao JinshengProfessor Lu Daru...