Molecular cloning and characterisation of the tissue inhibitor of metalloproteinase-3 gene from canine mammary tumour

Abstract

Inhibition of matrix metalloproteinases (MMPs) by tissue inhibitors of metalloproteinases (TIMPs) has been reported to decrease metastasis and tumour-associated angiogenesis. The present study is aimed at characterising the gene encoding TIMP-3 from canine mammary tumour. We identified and cloned the full-length cDNA encoding TIMP-3 from canine mammary tumour. The entire open reading frame consisted of 636 nucleotides and 213 residues (accession number JF508171). Nucleotide and translated protein sequence were close to Sus scrofa but clustered away from the rodent group. Synonymous substitution (dS) was higher than non-synonymous substitution (dN), suggesting that the TIMP-3 gene was not under positive selection and that no advantageous mutations had any significant role in its evolutionary adaptation. The predicted SWISS-MODEL of canine TIMP-3 protein is composed of 7 α-helices and 12 β-turns. The G-factor score for the TIMP-3 protein model based on Ramachandran plot was found to be −0.47 for dihedral bonds, −0.08 for covalent bonds and −0.31 overall, which suggests that the model obtained for TIMP-3 is a reliable one.