Martin D, Zusman S, Li X, Williams E L, Khare N, DaRocha S, Chiquet-Ehrismann R, Baumgartner S
Friedrich Miescher-Institut, CH-4002 Basel, Switzerland.
J Cell Biol. 1999 Apr 5;145(1):191-201. doi: 10.1083/jcb.145.1.191.
We report the molecular and functional characterization of a new alpha chain of laminin in Drosophila. The new laminin chain appears to be the Drosophila counterpart of both vertebrate alpha2 (also called merosin) and alpha1 chains, with a slightly higher degree of homology to alpha2, suggesting that this chain is an ancestral version of both alpha1 and alpha2 chains. During embryogenesis, the protein is associated with basement membranes of the digestive system and muscle attachment sites, and during larval stage it is found in a specific pattern in wing and eye discs. The gene is assigned to a locus called wing blister (wb), which is essential for embryonic viability. Embryonic phenotypes include twisted germbands and fewer pericardial cells, resulting in gaps in the presumptive heart and tracheal trunks, and myotubes detached from their target muscle attachment sites. Most phenotypes are in common with those observed in Drosophila laminin alpha3, 5 mutant embryos and many are in common with those observed in integrin mutations. Adult phenotypes show blisters in the wings in viable allelic combinations, similar to phenotypes observed in integrin genes. Mutation analysis in the eye demonstrates a function in rhabdomere organization. In summary, this new laminin alpha chain is essential for embryonic viability and is involved in processes requiring cell migration and cell adhesion.
我们报道了果蝇中一种新的层粘连蛋白α链的分子和功能特征。这种新的层粘连蛋白链似乎是脊椎动物α2（也称为黑素结合糖蛋白）和α1链在果蝇中的对应物，与α2的同源性略高，这表明该链是α1和α2链的祖先版本。在胚胎发育过程中，该蛋白与消化系统和肌肉附着部位的基底膜相关联，在幼虫阶段，它以特定模式存在于翅和眼盘中。该基因被定位到一个名为翅疱（wb）的位点，这对胚胎存活至关重要。胚胎表型包括扭曲的胚带和较少的心包细胞，导致推测的心脏和气管干出现间隙，以及肌管与其靶肌肉附着部位分离。大多数表型与在果蝇层粘连蛋白α3、5突变胚胎中观察到的表型相同，许多表型与在整合素突变中观察到的表型相同。成年表型在可行的等位基因组合中显示翅上有水泡，类似于在整合素基因中观察到的表型。眼睛中的突变分析表明其在小网膜组织中起作用。总之，这种新的层粘连蛋白α链对胚胎存活至关重要，并参与需要细胞迁移和细胞黏附的过程。
