Studying Of Molecular Biology About Gene Defect In Glycoprotein Ⅸ Associated With Bernard-Soulier Syndrome

Objective To identify a mutation G2113→A in the glycoprotein (GPK) gene associated with Bernard-Soulier syndrome (BSS) and to investigate BSS pathogenesis. Methods Allele-specific restriction enzyme was used to analyze patient, her mother and brother and 40 healthy volunteers. Site-directed mutagenesis was performed to construct a expression vector PD-KG2113A harboring the mutation G2113→A. Chinese hamster ovary (CHO) cells were transiently cotransfected with plasmids harboring the entire coding region of GP I b a, GP Iβ and GPK or mutant GPIX, respectively. Expression of GP I b a and GPK in transfected CHO cells were analyzed with flow cytometer. GP I b a and GPEX in the cytoplasm of transfected CHO cells were analyzed by immunostainning and westernblotting. Results The patient is the homozygosity of the subsitution, her mother and her brother were found to be heterozygous. Expression of GP I b a and GPK in mutant CHO cells were remarkably reduced, but they were aboundant in the cytoplasma. Conclusion Our results showed that the mutation of Alal39(GCC) →Thr(ACC) in the GPK does not affect synthesis and assembly of GP I b-K-V complex but influence its anchoring and expression on the cell surface, which was responsible for BSS.