Construction and expression of the recombinant human immunodeficiency virus Tat gene and analysis on its biological characteristics / 中华传染病杂志

ABSTRACT

Objective To determine the influence of protein fusion on the biological characteris- tics of hymidine kinase(TK)and human immunodeficiency virus(HIV)Tat recombinant protein. Methods By utilizing polymerase chain reaction(PCR)technique,different fragments containing two,four or six glycines(Gly)were inserted between the HIV Tat gene and TK,and cloned into PBK vector.After testified by sequencing,the vectors were transfected into E coli.After induced by iso- propyl thiogalactose(IPTG),bacilli were collected and destructed by ultrasonic,the fusion proteins were determined by monoclonal antibody against HIV protein.HepG2 cells were incubated in DMEM supplement with 10?g/mL HIV-Gly(n)-TK(n=0,2,4,6)fusion protein,TK-HIV Tat and only HIV Tat.HepG2 cells in different groups were detected by immunofluorescence assay 24 hours after transduction with HIV Tat monoclonal antibody.The rate of apoptosis after cells were incubated with gencilovir(10?g/mL)for 3 days was determined by cell flow cytometry,while survival cell ratio was recorded by trypan blue.The data were analyzed by statistics(t-test).Results The Tat-Gly(n)-TK (n= 0,2,4,6)recombinant genes were constructed and inserted into PBK vectors,which were expressed in E coli and then purified.Cells in different groups,which were incubated with Tat-Gly (n)-TK(n=0,2,4,6)fusion proteins,Tat-TK fusion protein,TK-Tat fusion proteins or only Tat proteins respectively,were detected by immunofluorescence assay.The intensities of fluorescence in different groups were almost same,but the ratios of cell survival or apoptosis were different.The highest ratio of cells apoptosis(14.77%)was in the group that cellular culture medium was mixed with Tat-Gly(4)-TK fusion protein,followed by the groups containing 6,2 glycines or no TK gene in genes(4.30%,12.69% and 1.03%,respectively).There were significant differences between each 2 groups among the all groups(t-test,P