AIM:To clone the cDNA of UGT1 A9 from a Chinese humanliver and establish the Chinese hamster lung(CHL)cell lineexpressing human UGT1 A9.METHODS:cDNA of UGTI A9 was transcripted from mRNAby reverse transcriptese-ploymerase chain reaction,and wascloned into the pGEM-T vector which was amplified in thehost bacteric E.Coll DH5α.The inserted fragment,verifiedby DNA sequencing,was subcloned into the Hind Ⅲ/Not 1site of a mammalian expression vector pREP9 to constructthe plasmid termed pREP9-UGT1A9.CHL cells weretmnsfected with the resultant recombinents,pREP9-UGT1A9,and selected by G418(400 rag.L~(-1))for onemonth.The surviving clone(CHL-UGT1A9) was harvestedas a pool and sub-cultured in medium containing G418 toobtain samples for UGT1 A9 assays.The enzyme activity ofCHL-UGT1 A9 towards proprenolol in S9 protein of the cellwas determined by HPLC.RESULTS:The sequence of the cDNA segment cloned,which was 1666 bp in length,was identical to that releasedby Gene Bank(GenBank accession number:AF056188)incoding region.The recombinant constructed,pREP9-UGT1 A9,contains the entire coding region,along with 18bp of the 5’ and 55 bp of the 3’ untranslated region of theUGT1 A9 cDNA,respectively.The cell lines establishedexpressed the protein of UGT1 A9,and the enzyme activitytowards propranolol in S9 protein was found to he 101±24pmol·min~(-1)·mg~(-1) protein(n=3),but was not detectable inparental CHL cells.CONCLUSION:The cDNA of UGT1A9 was successfullycloned from a Chinese human liver and transfected into CHLcells.The CHL-UGT1 A9 cell lines established efficientlyexpressed the protein of UGT1 A9 for the further enzymestudy of drug glucuronidstion. AIM: To clone the cDNA of UGT1 A9 from a Chinese humanliver and establish the Chinese hamster lung (CHL) cell line expressing human UGT1 A9.METHODS: cDNA of UGTI A9 was transcripted from mRNA by reverse transcriptese-ploymerase chain reaction, and wascloned into the pGEM -T vector which was amplified in thehost bacteric E.Coll DH5α. The inserted fragment, verified by DNA sequencing, was subcloned into the Hind III / Not 1site of a mammalian expression vector pREP9 to construct the plasmid termed pREP9-UGT1A9.CHL cells were tmnsfected with the resulting recombinents, pREP9-UGT1A9, and selected by G418 (400 rag.L -1) for one month. survivor clone (CHL-UGT1A9) was harvestedas a pool and sub-cultured in medium containing G418 toobtain samples for UGT1 A9 assays. The enzyme activity of CHL-UGT1 A9 towards proprenolol in S9 protein of the cell is determined by HPLC .RESULTS: The sequence of the cDNA segment cloned, which was 1666 bp in length, was identical to that released by Gene Bank (GenBank accession number: A F056188) incoding region. The recombinant construct, pREP9-UGT1 A9, contains the entire coding region, along with 18 bp of the 5 ’and 55 bp of the 3’ untranslated region of the UGT1 A9 cDNA, respectively. The cell lines establishedexpressed the protein of UGT1 A9, and the enzyme activity in propranolol in S9 protein was found to he 101 ± 24 pmol·min -1 (mg -1) protein (n = 3), but was not detectable in parental CHL cells. CONCLUSION: The cDNA of UGT1A9 was successfully cloned from a Chinese human liver and transfected into CHL cells. The CHL-UGT1 A9 cell lines are much more capable of expressing the protein of UGT1 A9 for the further enzyme study of drug glucuronids.