Mouse gelatinase B

cDNA cloning, regulation of expression and glycosylation in WEHI-3 macrophages and gene organisation


  • Note. The novel nucleotide sequence data published here have been deposited with the EMBL GenBank and DDBT sequence data banks and are available under the accession numbers X72794 and X72795, for the gene and cDNA, respectively.

Correspondence to G. Opdenakker, Rega Institute for Medical Research, University of Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium
Fax:+32 16 337340.


Gelatinase B is a regulated matrix metalloproteinase with an important role in the remodelling of extracellular matrices and of basement membranes. To study the structure and function of gelatinase B in the mouse, the cDNA was cloned from a macrophage cell line (WEHI-3). Using this cDNA, a cosmid clone with the mouse gene was isolated. The complete gene (8 kbp) was sequenced and compared with the human gene structure. There was 78% similarity at the cDNA level and the exon/intron structure of the murine gene was similar to the human counterpart. At the 5′ untranslated side, 1200 bp of the promoter/enhancer region were sequenced and found to contain several trans-acting-factor-binding sites. The mRNA transcription-initiation site was determined by non-isotopic primer-extension analysis. Polymerase-chain-reaction amplification of cDNAs yielded indirect evidence for a reverse-transcription stop in WEHI-3 cell mRNA. The DNA-derived mouse-protein structure exhibited 82% similarity with the human one. This similarity was functionally reflected by cross-reactivity of the mouse protein with an antiserum against human gelatinase B. The production of murine gelatinase B was studied at the protein level by zymography and at the mRNA level by Northern blot analysis. In WEHI-3 cells the gelatinase B protein is induced by bacterial lipopolysaccharide, phorbol ester, double-stranded RNA and the cytokine interleukin-1. Regulation of activity and structural heterogeneity of gelatinase B in WEHI-3 cells were shown to occur at the gene regulatory level, by expression of the matrix metalloproteinase inhibitor TIMP-1, and by glycosylation of the secreted protein.