OBJECTIVEHuman soluble tumor necrosis factor receptor (sTNFR) can interfere with the biological functions of interleukin-1, which may be appropriate to the treatment of periodontitis. The eukaryote expression vector of the human sTNFR gene must be constructed prior to conducting transgene therapy of periodontitis.

METHODSBoth sTNFR gene and plasmid pcDNA 3.1 (+) DNA were digested with Kpn I and Xho I. After purification, the two fragments were ligated by TakaRa DNA Ligation Kit (Ver 2.0). This recombinant DNA was then transformed into E. Coli Competent Cells JM109 and positive clones were selected on the LB agarose plate containing ampicillin (80 microg/ul).

RESULTSSix single clones were indentified by double digestion with kpn I and xho I and two fragments with the size of 5.4 kb and 1.0 kb were produced as expected.

CONCLUSIONThe sTNFR gene was successfully inserted into the eukaryote expression vector plasmid pcDNA 3.1 (+) by recombination technology in vitro.