The metalloproteinase matrilysin is preferentially expressed by epithelial cells in a tissue-restricted pattern in the mouse.

Abstract

To explore the role of the matrix metalloproteinase matrilysin (MAT) in normal tissue remodeling, we cloned the murine homologue of MAT from postpartum uterus using RACE polymerase chain reaction and examined its pattern of expression in embryonic, neonatal, and adult mice. The murine coding sequence and the corresponding predicted protein sequence were found to be 75% and 70% identical to the human sequences, respectively, and organization of the six exons comprising the gene is similar to the human gene. Northern analysis and in situ hybridization revealed that MAT is expressed in the normal cycling, pregnant, and postpartum uterus, with levels of expression highest in the involuting uterus at early time points (6 h to 1.5 days postpartum). The mRNA was confined to epithelial cells lining the lumen and some glandular structures. High constitutive levels of MAT transcripts were also detected in the small intestine, where expression was localized to the epithelial Paneth cells at the base of the crypts. Similarly, MAT expression was found in epithelial cells of the efferent ducts, in the initial segment and cauda of the epididymis, and in an extra-hepatic branch of the bile duct. MAT transcripts were detectable only by reverse transcription-polymerase chain reaction in the colon, kidney, lung, skeletal muscle, skin, stomach, juvenile uterus, and normal, lactating, and involuting mammary gland, as was expression primarily late in embryogenesis. Analysis of MAT expression during postnatal development indicated that although MAT is expressed in the juvenile small intestine and reproductive organs, the accumulation of significant levels of MAT mRNA appears to correlate with organ maturation. These results show that MAT expression is restricted to specific organs in the mouse, where the mRNA is produced exclusively by epithelial cells, and suggest that in addition to matrix degradation and remodeling, MAT may play an important role in the differentiated function of these organs.

Misregulation of Stromelysin-1 Expression in Mouse Mammary Tumor Cells Accompanies Acquisition of Stromelysin-1-dependent Invasive Properties

“…Blots were washed in 2 ϫ SSPE containing 0.1% SDS, 0.5 ϫ SSPE containing 0.1% SDS and 0.1 ϫ SSPE containing 0.1% SDS, each step for 1 h at 55°C. The cDNA fragments used for random priming for SL3 (21), matrilysin (22), MT-MMP (21), gelatinases A (21) and B (21), TIMP1 (21), TIMP3 (23), and 28 S RNA (21) have been described. cDNA for mouse SL1 was cloned with SL1-specific primers as specified in the following section.…”

Why are epididymal tumours so rare?

“…128 MMP7 (matrilysin) is a target gene of the Wnt/b-catenin pathway 129 (see section on 'Growth promoters') and is expressed in the efferent ducts and initial segment of mice. 130 This unusual presence in epithelial cells suggests that the protein is involved in tissue development rather than tumourigenesis; 131 indeed, transgenic mice overexpressing MMP7 in the epididymis exhibit the protein in a structurally normal organ. 132 Erythropoietin promotes tumour growth Figure 3 Representative factors found in the epididymis that are involved in pro-cancer and tumour suppression mechanisms in cancer-prone tissues.…”

Matrilysin (Matrix Metalloproteinase-7) Mediates E-Cadherin Ectodomain Shedding in Injured Lung Epithelium

“…Matrilysin (MMP-7), unlike many MMPs, is expressed by noninjured, noninflamed mucosal epithelia in most adult human tissues. 11,12 In the human lung, matrilysin is constitutively expressed in tracheal glands and in tracheobronchial epithelium, and expression is acutely up-regulated by injury or exposure to bacteria. 13,14 Work in our laboratory demonstrated that matrilysin is prominently expressed in injured airways and is necessary for airway mucosal repair, 13 indicating that this a critical extracellular proteinase in repair processes.…”