Kiyozumi Daiji, Taniguchi Yukimasa, Nakano Itsuko, Toga Junko, Yagi Emiko, Hasuwa Hidetoshi, Ikawa Masahito, Sekiguchi Kiyotoshi
Laboratory of Extracellular Matrix Biochemistry, Institute for Protein Research, Osaka University, Osaka, Japan.
Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.
Life Sci Alliance. 2018 Sep 10;1(5):e201800064. doi: 10.26508/lsa.201800064. eCollection 2018 Oct.
Laminin-integrin interactions regulate various adhesion-dependent cellular processes. γ1C-Glu, the Glu residue in the laminin γ1 chain C-terminal tail, is crucial for the binding of γ1-laminins to several integrin isoforms. Here, we investigated the impact of γ1C Glu to Gln mutation on γ1-laminin binding to all possible integrin partners in vitro, and found that the mutation specifically ablated binding to α3, α6, and α7 integrins. To examine the physiological significance of γ1C-Glu, we generated a knock-in allele, , in which the γ1C Glu to Gln mutation was introduced. Although homozygotes developed into blastocysts and deposited laminins in their basement membranes, they died just after implantation because of disordered extraembryonic development. Given the impact of the allele on embryonic development, we developed a knock-in mouse strain enabling on-demand introduction of the γ1C Glu to Gln mutation by the Cre-loxP system. The present study has revealed a crucial role of γ1C-Glu-mediated integrin binding in postimplantation development and provides useful animal models for investigating the physiological roles of laminin-integrin interactions in vivo.
层粘连蛋白-整合素相互作用调节各种依赖黏附的细胞过程。γ1C-谷氨酸，即层粘连蛋白γ1链C末端尾巴中的谷氨酸残基，对于γ1-层粘连蛋白与几种整合素亚型的结合至关重要。在此，我们研究了γ1C谷氨酸突变为谷氨酰胺对γ1-层粘连蛋白在体外与所有可能的整合素伴侣结合的影响，发现该突变特异性地消除了与α3、α6和α7整合素的结合。为了研究γ1C-谷氨酸的生理意义，我们构建了一个敲入等位基因，其中引入了γ1C谷氨酸突变为谷氨酰胺的突变。尽管纯合子发育成囊胚并在其基底膜中沉积层粘连蛋白，但由于胚外发育紊乱，它们在着床后不久就死亡了。鉴于该等位基因对胚胎发育的影响，我们开发了一种敲入小鼠品系，通过Cre-loxP系统能够按需引入γ1C谷氨酸突变为谷氨酰胺的突变。本研究揭示了γ1C-谷氨酸介导的整合素结合在着床后发育中的关键作用，并为研究层粘连蛋白-整合素相互作用在体内的生理作用提供了有用的动物模型。
