Kumar J M, Bond J S
Department of Biochemistry and Molecular Biology, H171, Pennsylvania State University, College of Medicine, 500 University Drive, 17033-0850, Hershey, PA, USA.
Biochim Biophys Acta. 2001 Mar 19;1518(1-2):106-14. doi: 10.1016/s0167-4781(01)00188-9.
Meprins are secreted and membrane-bound metalloendopeptidases highly expressed in kidney and intestinal epithelial cells. They are oligomeric glycoproteins composed of evolutionarily related alpha and/or beta subunits. The present work revealed that the messages for both meprin subunits were expressed in intestine and kidney in ICR and C3H/He mouse embryos (as early as day 11), indicating developmental functions for both subunits. During the first 2 weeks after birth, the mRNA levels for both subunits increased in ICR mice, but between 10 days and 3 weeks (time of weaning) the alpha subunit level in the intestine fell markedly. In adult ICR mice, meprin beta mRNA was consistently expressed in both kidney and intestine, whereas meprin alpha mRNA was highly expressed in kidney but only present at low levels in intestine. In C3H/He mice, the pattern of meprin alpha and beta subunit mRNA expression was similar to that of ICR mice, except that meprin alpha was barely detectable in kidney after birth. The results of postnatal studies indicate that the meprin alpha subunit has a role in the intestine during suckling but is not essential after weaning, and that the beta homooligomer is the major meprin form after weaning in both kidney and intestine.
膜金属蛋白酶是分泌型和膜结合型金属内肽酶，在肾脏和肠道上皮细胞中高度表达。它们是由进化相关的α和/或β亚基组成的寡聚糖蛋白。目前的研究表明，在ICR和C3H/He小鼠胚胎中（早在第11天），肠道和肾脏中均表达了两种膜金属蛋白酶亚基的信息提示这两种亚基均具有发育功能。出生后的前2周，两种亚基的mRNA水平在ICR小鼠中均升高，但在10天至3周（断奶时间）之间，肠道中的α亚基水平明显下降。在成年ICR小鼠中，膜金属蛋白酶β mRNA在肾脏和肠道中均持续表达，而膜金属蛋白酶α mRNA在肾脏中高表达，但在肠道中仅以低水平存在。在C3H/He小鼠中，膜金属蛋白酶α和β亚基mRNA的表达模式与ICR小鼠相似，只是出生后在肾脏中几乎检测不到膜金属蛋白酶α。产后研究结果表明，膜金属蛋白酶α亚基在哺乳期间在肠道中起作用，但断奶后并非必需，并且β同型寡聚体是断奶后肾脏和肠道中主要的膜金属蛋白酶形式。
