Reponen P, Sahlberg C, Huhtala P, Hurskainen T, Thesleff I, Tryggvason K
Biocenter Oulu, University of Oulu, Finland.
J Biol Chem. 1992 Apr 15;267(11):7856-62.
We report the isolation of a cDNA clone providing the first and complete sequence of mouse 72-kDa type IV collagenase. The clone contains 2800 nucleotides with a 1986-nucleotide open reading frame coding for 662 amino acids. The amino acid sequence includes a 29-residue signal peptide, an 80-residue propeptide, and a 553-residue enzyme proper. The sequence identity between the mouse and human enzymes is 96% with all cysteine residues conserved. The carboxyl-terminal domain of the mouse enzyme contains two more residues than the human enzyme. Northern hybridization analysis revealed considerable expression of the enzyme gene in newborn mouse lung, heart, kidney, and psoas muscle tissues, whereas only weak or no signals were observed in liver, spleen, and brain. Expression of the gene was substantially reduced in the same tissues of 3-month-old mice. In situ hybridization analysis of 72-kDa type IV collagenase expression in 10-15-day-old mouse embryos showed that the gene was intensely expressed in mesenchymal cells. Brain and surface ectoderm were completely negative. The epithelial tissue component of developing organs was negative with the exception of salivary gland. Although the expression varied somewhat between different mesenchymal tissues, no temporal or spatial changes could be associated with the advancement of epithelial branching morphogenesis. These findings together with our previous data on the expression of 72-kDa type IV collagenase in human tumors indicate that this enzyme has some very specific roles both in the physiological and pathological degradation of extracellular matrix. Furthermore, it has become clear that the closely related 92-kDa type IV collagenase differs completely with respect to expression pattern as well as gene regulation. The mouse cDNA clones reported in this study may provide important tools unraveling the actual roles of these enzymes in vivo.
我们报道了一个cDNA克隆的分离，它提供了小鼠72 kDa IV型胶原酶的首个完整序列。该克隆包含2800个核苷酸，有一个1986个核苷酸的开放阅读框，编码662个氨基酸。氨基酸序列包括一个29个残基的信号肽、一个80个残基的前肽和一个553个残基的酶本身。小鼠和人类酶之间的序列同一性为96%，所有半胱氨酸残基均保守。小鼠酶的羧基末端结构域比人类酶多两个残基。Northern杂交分析显示该酶基因在新生小鼠肺、心脏、肾脏和腰大肌组织中有大量表达，而在肝脏、脾脏和大脑中仅观察到微弱或无信号。在3个月大的小鼠的相同组织中，该基因的表达大幅降低。对10 - 15天大的小鼠胚胎中72 kDa IV型胶原酶表达的原位杂交分析表明，该基因在间充质细胞中强烈表达。脑和表面外胚层完全呈阴性。除唾液腺外，发育器官的上皮组织成分呈阴性。尽管不同间充质组织之间的表达有所差异，但上皮分支形态发生的进展与时间或空间变化无关。这些发现以及我们之前关于72 kDa IV型胶原酶在人类肿瘤中表达的数据表明，该酶在细胞外基质的生理和病理降解中具有一些非常特殊的作用。此外，已经清楚的是，密切相关的92 kDa IV型胶原酶在表达模式和基因调控方面完全不同。本研究报道的小鼠cDNA克隆可能为揭示这些酶在体内的实际作用提供重要工具。
