[In vitro expression activity of α-(1,2) fucosyltransferase with 35C > T and 682A > G mutations].

In order to explore the effects of 35C > T and 682A > G mutations on the activity of alpha-(1,2) fucosyltransferase, the coding region of fut1 gene was amplified by polymerase chain reaction (PCR) from genomic DNA. PCR product was ligated into expression vector using TOPO TA cloning kit to obtain the recombinant plasmids. The recombinant plasmids were transfected into COS-7 cells by liposome method. After screening by using G418, H antigen expression on the COS-7 was tested by flow cytometry and fut1 mRNA was detected by real-time PCR. The results indicated that three kinds of recombinant plasmids pcDNA3.1/V5-His-wild (35C + 682A), pcDNA3.1/V5-His-35T and pcDNA3.1/V5-His-35T-682G were successfully constructed. After transfection, the H antigen expressed on membrane of COS-7 cells at the second day, with the maximum level of expression at the fourth day. When compared with pcDNA3.1/V5-His-wild transfected cells, the H antigen expression level of the 35T and 682G + 35T recombinant plasmids in the transfected cells was 52.7% and 13.3% on the fourth day, respectively. Although the level of fut1 mRNA decreased with prolonging of time, the mRNA expressed on the pcDNA3.1/V5-His-35T-682G transfected cells reached to 14% of the wild plasmids on the first day. It is concluded that 682A > G mutation obviously reduces the activity of alpha-(1,2) fucosyltransferase, while 35C > T mutation leads to partial reduction of H antigen in vitro expression.