STRUCTURE AND CHARACTERIZATION OF THE HUMAN TISSUE INHIBITOR OF METALLOPROTEINASES-2 GENE

We report here the characterization of the human tissue inhibitor of m etalloproteinases-2 (TIMP-2) gene. The gene is 83 kilobase pairs (kb) long with exon-intron splicing sites located in preserved positions am ong the three members of the TIMP family. A 2.6-kb genomic DNA fragmen t flanking the 5'-end of the gene contains several regulatory elements including five Sp1, two AP-2, one AP-1, and three PEA-3 binding sites , Despite the presence of a complete AP-1 consensus at position -281, the promoter did not respond to 12-O-tetradecanoylphorbol-13-acetate t reatment; However, 12-O-tetradecanoylphorbol-13-acetate response was g enerated by insertion of a similar AP-1 consensus at position -71, ind icating the importance of the positioning of this motif. The promoter contains a typical CpG island; however, methylation of this island did not seem to influence gene expression. Analysis of the 3'-end of the gene revealed that the two mRNAs for TIMP-2 (1.2 and 3.8 kb) differ by the selection of their polyadenylation signal sites, but selection of these sites does not affect RNA stability. In summary, the TIMP-2 gen e has several features observed in housekeeping genes, and differs sig nificantly from TIMP-1 and TIMP-3 genes. These differences are likely to explain the specific roles that these inhibitors play in the regula tion of matrix metalloproteinases.