Identification and Enzymatic Characterization of Two Diverging Murine Counterparts of Human Interstitial Collagenase (MMP-1) Expressed at Sites of Embryo Implantation

Abstract

Remodeling of fibrillar collagen in mouse tissues has been widely attributed to the activity of collagenase-3 (matrix metalloproteinase-13 (MMP-13)), the main collagenase identified in this species. This proposal has been largely based on the repeatedly unproductive attempts to detect the presence in murine tissues of interstitial collagenase (MMP-1), a major collagenase in many species, including humans. In this work, we have performed an extensive screening of murine genomic and cDNA libraries using as probe the full-length cDNA for human MMP-1. We report the identification of two novel members of the MMP gene family which are contained within the cluster of MMP genes located at murine chromosome 9. The isolated cDNAs contain open reading frames of 464 and 463 amino acids and are 82% identical, displaying all structural features characteristic of archetypal MMPs. Comparison for sequence similarities revealed that the highest percentage of identities was found with human interstitial collagenase (MMP-1). The new proteins were tentatively called Mcol-A and Mcol-B (Murine collagenase-like A and B). Analysis of the enzymatic activity of the recombinant proteins revealed that both are catalytically autoactivable but only Mcol-A is able to degrade synthetic peptides and type I and II fibrillar collagen. Both Mcol-A and Mcol-B genes are located in the A1-A2 region of mouse chromosome 9, Mcol-A occupying a position syntenic to the human MMP-1 locus at 11q22. Analysis of the expression of these novel MMPs in murine tissues revealed their predominant presence during mouse embryogenesis, particularly in mouse trophoblast giant cells. According to their structural and functional characteristics, we propose that at least one of these novel members of the MMP family, Mcol-A, may play roles as interstitial collagenase in murine tissues and could represent a true orthologue of human MMP-1.

Matrix Metalloproteinase Mmp-1a Is Dispensable for Normal Growth and Fertility in Mice and Promotes Lung Cancer Progression by Modulating Inflammatory Responses

“…Interestingly, this difference was more marked in male than in female mutant mice, indicating the occurrence of a gender difference that has been previously reported in other models of Mmp deficiency (24). The different susceptibility of male and female Mmp1a Ϫ/Ϫ mice to tumor development is likely due to hormonal factors as previously demonstrated in the Mmp8-null model, in which ovariectomy or estrogen receptor antagonist treatment increases the incidence of chemically induced tumors in Mmp8 Ϫ/Ϫ female mice, and abrogates the gender differences in cancer susceptibility (22). Similar studies in Mmp1a-null mice will be necessary to confirm the hormonal basis of the gender differences in cancer susceptibility in these mutant animals.…”

“…One possibility to explain this lack of functional information about MMP-1 in cancer is the absence of an in vivo model of MMP-1 deficiency, an aspect that has been largely attributed to the wide assumption that no MMP-1 ortholog was present in rodents. However, our finding of two murine genes (Mmp1a and Mmp1b, also known as McolA and McolB) similar to human MMP-1 opened a series of further studies, which allowed us to conclude that Mmp1a is a bona fide counterpart of human MMP-1 (22). This finding was the starting point of a long term work that has now led us to the generation and analysis of mutant mice deficient in Mmp1a.…”

“…However, functional and mechanistic studies on the relevance of MMP-1 in cancer have been hampered by the absence of an in vivo model of MMP1 deficiency. To address this question, we have undertaken studies to generate mutant mice deficient in Mmp1a, the mouse orthologous gene of human MMP1 (22). In this work, we describe the generation of Mmp1a…”

Control of matrix metalloproteinase catalytic activity

“…Mcol-A and -B are likely the murine homologues of MMP-1 (Balbin et al, 2001). Based on its chromosome position and enzymatic activity, Mcol-A is a strong candidate to be the murine orthologue of human MMP-1.…”

Dysregulation of TGF-β1 receptor activation leads to abnormal lung development and emphysema-like phenotype in core fucose-deficient mice

“…Furthermore, MMP-2, MMP-9, and MMP-12 lead to emphysema by degradation of elastin fibers (25,26). Therefore, expression levels of collagens, elastin, and a number of MMPs of putative relevance in lung pathology, including McolB (a mouse orthologue of human MMP-1) (27) and MMP-2, -8, -9, -12, -13, and -14, were examined in the lungs of Fut8-mutant mice. RT-PCR analysis showed that there were no significant changes in the expression levels of collagens, MMP-2, -8, and -14 in lung tissues from Fut8 Ϫ/Ϫ , Fut8 ϩ/Ϫ , and Fut8 ϩ/ϩ mice (Fig.…”