Molecular characteristics of equine stromelysin and the tissue inhibitor of metalloproteinase 1.

OBJECTIVE

To clone the entire coding sequence of equine matrix metalloproteinase-3 (MMP-3, stromelysin) and tissue inhibitor of metalloproteinase-1 (TIMP-1) and compare their nucleotide and amino acid sequences with those of MMP-3 and TIMP-1 from other species.

SAMPLES

Articular cartilage harvested from the joints of 4 foals, 2 yearlings, and 3 adult horses.

PROCEDURE

A cDNA library was constructed from mRNA extracted from equine chondrocytes. The library was screened and clones selected that contained the cDNA for MMP-3 and TIMP-1. The cDNA was sequenced and the nucleotide and deduced amino acid sequences compared with known sequences in other species. Northern blot analysis was performed, using the resulting cDNA clones.

RESULTS

An 1803-bp cDNA for MMP-3 including the entire coding sequence of 1434 bases was cloned and sequenced. A 744-bp cDNA for TIMP-1 including the entire coding sequence of 624 bases was cloned and sequenced. Northern analysis revealed MMP-3 to hybridize to a single mRNA species at approximately 2.1 kb. TIMP-1 hybridized to a single mRNA species at approximately 0.8 kb.

CONCLUSIONS

MMP-3 and TIMP-1 were highly homologous to that of other species at the nucleotide and amino acid level although each had unique residues in part of the peptide that is generally conserved.

CLINICAL RELEVANCE

Understanding the molecular structure of MMP-3 and TIMP-1 and the availability of their cDNA should allow a more detailed understanding of their balance in cartilage and the degradative processes in joint disease.