Molecular dissection of laminin α5 in vivo reveals separable domain-specific roles in embryonic development and kidney function
Molecular dissection of laminin α5 in vivo reveals separable domain-specific roles in embryonic development and kidney function
复制标题
DOI：
10.1016/j.ydbio.2006.04.463
复制
发表时间：
2006-08-01
影响因子：
2.7
通讯作者：
Miner, Jeffrey H.
中科院分区：
文献类型：
--
作者：
Kikkawa, Yamato;Miner, Jeffrey H.
层粘连蛋白是一个基底膜蛋白家族，在上胚极化和原肠胚形成等基本发育过程以及器官发育和功能中发挥着不同的作用。我们已经集中在层粘连蛋白α 1和α 5链上，这是发育所需的祖先层粘连蛋白α链。为了阐明层粘连蛋白α 1和α 5及其COOH-末端LG结构域的独特功能，我们已经产生了表达全长和嵌合层粘连蛋白α 5/α 1链的层粘连蛋白敲除和转基因小鼠的集合。将转基因杂交到Lama 5-/-背景上产生“假敲入”，之所以这样称呼是因为内源性层粘连蛋白α 5被转基因编码的蛋白质取代。整个α 5LG结构域被α 1 LG取代的嵌合体的表达对在Lama 5-/-胚胎中观察到的缺陷具有最小的改善作用。相比之下，仅α 5 LG 3 -5串联体被α 1 LG 3 -5替换的嵌合体的高水平表达完全挽救了指分隔、神经管闭合、胎盘迷路形态、肺叶分隔、毛发生长和肾小球血管化的缺陷。这些小鼠存活了几个月，但它们发展成了致命的肾病综合征。我们的研究结果表明：（1）层粘连蛋白α 5LG 1 -2串联体在发育过程中起重要作用，并具有α 5LG结构域的绝大多数功能;（2）α 5LG 3 -5串联体作为肾脏肾小球滤过屏障对血浆蛋白所需的新决定子。(c)2006年爱思唯尔公司All rights reserved.
Laminins are a family of basement membrane proteins with diverse roles in fundamental developmental processes such as epiblast polarization and gastrulation, as well as in organ development and function. We have focused on the laminin alpha 1 and alpha 5 chains, the ancestral laminin a chains required for development. To elucidate the unique functions of laminin alpha 1 and alpha 5 and their COOH-terminal LG domains, we have produced a collection of laminin knockout and transgenic mice expressing full length and chimeric laminin alpha 5/alpha 1 chains. Crossing the transgenes onto the Lama5-/- background generates "pseudo-knockins", so called because endogenous laminin alpha 5 is replaced by transgene-encoded proteins. Expression of a chimera with the entire alpha 5LG domain replaced by alpha 1LG had minimal ameliorative effects on the defects observed in Lama5-/- embryos. In contrast, high level expression of a chimera with only the alpha 5LG3-5 tandem replaced by alpha 1LG3-5 completely rescued defects in digit septation, neural tube closure, placental labyrinth morphology, lung lobe septation, hair growth, and vascularization of kidney glomeruli. These mice were viable for several months, but they developed a lethal nephrotic syndrome. Our results show that: (1) the laminin alpha 5LG1-2 tandem plays an essential role during development and harbors the great majority of the functionality of the alpha 5LG domain; and (2) the alpha 5LG3-5 tandem serves as a novel determinant required for the kidney's glomerular filtration barrier to plasma protein. (c) 2006 Elsevier Inc. All rights reserved.