ABSTRACT
AIM: To construct prokaryotic expression vector of His-tagged human IP-10 for further study of its biological function in the inflammatory response. METHODS: The coding sequence of IP-10 lacking signal peptide was amplified from human lung cDNA library by polymerase chain reaction (PCR) and the fragment was cloned into pET-14b plasmid for the construction of His-tagged fusion protein expressing vector, pET-14b/IP-10. After being identified by enzyme digestion and sequencing, the recombinant vector was transformed into a strain of E. coli, BL21 (DE_3). The expression of His-tagged fusion protein was induced with IPTG and purified with Ni+-NTA affinity chromatography. Then the chemotactic activity of IP-10 was determined by transwell migration assay on THP-1 cells. RESULTS: The construction of pET-14b/IP-10 recombinant vector was proved by enzyme digestion and sequencing. The fusion protein IP-10, which was purified by a routine Ni+ affinity method, had an activity on the induction of cell migration of THP-1. CONCLUSION: We successfully construct IP-10 fusion protein expressing vector and get the fusion protein with high bioactivity, which provides essential materials for the future studies on IP-10.
ABSTRACT
AIM: To construct the plasmid vectors containing different regions of human eNOS promoter coupled to a red fluorescent protein reporter gene, which may express in mammalian cells. METHODS: Different regions of human eNOS promoter were subcloned respectively into a red fluorescent protein vector, pDsRed1-1. These recombinant vectors, pDsF1033Red, pDsF494Red and pDsF166Red, were then transfected into NIH3T3 cell lines, followed by the observation under a fluorescent microscope. RESULTS: After identified to be right by double restriction enzyme digestion, PCR and sequencing, the vectors might be effectively expressed in NIH3T3 cells. 95 % of the red fluorescent emitted by a red fluorescent protein dispersed all over the cells, appearing at 48-60 h after transfection, reaching peak at 96-144 h, becoming the strongest in light at 144 h, gradually disappearing after 168 h and remaining little red fluorescent in 21 days. The quantity and intensity in expressions of red fluorescent protein drived by different regions of human eNOS promoter were clearly lower than by a strong promoter, p CMVIE . CONCLUSION: The red fluorescent protein reporter gene vectors containing different regions of human eNOS promoter are successfully constructed and may efficaciously express in mammalian cells, appearing not strong transcriptional activities, which provide practical and feasible tools to study functions of different regions of human eNOS promoter and roles of cis-elements in it. [