title: Mutations in the S gene region of hepatitis B virus genotype D in Turkish patients.
abstract: The S gene region of the hepatitis B virus (HBV) is responsible for the expression of surface antigens and includes the 'a'-determinant region. Thus, mutation(s) in this region would afford HBV variants a distinct survival advantage, permitting the mutant virus to escape from the immune system. The aim of this study was to search for mutations of the S gene region in different patient groups infected with genotype D variants of HBV, and to analyse the biological significance of these mutations. Moreover, we investigated S gene mutation inductance among family members. Forty HBV-DNA-positive patients were determined among 132 hepatitis B surface antigen (HbsAg) carriers by the first stage of seminested PCR. Genotypes and subtypes were established by sequencing of the amplified S gene regions. Variants were compared with original sequences of these serotypes, and mutations were identified. All variants were designated as genotype D and subtype ayw3. Ten kinds of point mutations were identified within the S region. The highest rates of mutation were found in chronic hepatitis patients and their family members. The amino acid mutations 125 (M -> T) and 127 (T -> P) were found on the first loop of 'a'-determinant. The other consequence was mutation inductance in a family member. We found some mutations in the S gene region known to be stable and observed that some of these mutations affected S gene expression.
authors.affiliation: Department of Biology, University of Gaziantep, 27310 Gaziantep, Turkey. ozaslansmd@yahoo.com
authors.forename: Mehmet
authors.initials: M
authors.lastname: Ozaslan
authors.forename: Ersan
authors.initials: E
authors.lastname: Ozaslan
authors.forename: Arzu
authors.initials: A
authors.lastname: Barsgan
authors.forename: Mehmet
authors.initials: M
authors.lastname: Koruk
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004279:DNA, Viral / Q000235:genetics; D005260:Female; D005814:Genes, Viral; D006509:Hepatitis B / Q000635:transmission / Q000821:virology; D006514:Hepatitis B Surface Antigens / Q000235:genetics*; D006515:Hepatitis B virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D018445:Infectious Disease Transmission, Vertical; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D017386:Sequence Homology, Amino Acid; D014421:Turkey
chemical_list: D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens