Cachaço Ana Sofia, Pereira Carlos Silva, Pardal Rita G, Bajanca Fernanda, Thorsteinsdóttir Sólveig
Departamento de Biologia Animal, Centro de Biologia Ambiental, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal.
Dev Dyn. 2005 Apr;232(4):1069-78. doi: 10.1002/dvdy.20280.
Cells interact with the extracellular matrix through receptors, most commonly of the integrin family. We (Cachaco et al. [2003] Development 130:1659-1671) and others (Schwander et al. [2003] Dev. Cell 4:673-685) have demonstrated a role for beta1 integrins in mouse primary myogenesis. However, it is unclear what alpha subunits pair with beta1 during this process in vivo. Here, we determined alpha subunit expression patterns at embryonic day (E) 11.5-E14.5. Differentiated myotomal myocytes express all alpha subunits studied. As the muscle masses form both in trunk (E12.5) and limbs (E11.5-E12.5), laminin receptors alpha6beta1 and alpha7beta1 are undetectable, and an assembled laminin matrix is absent. Instead alpha1beta1, alpha4beta1, alpha5beta1, and an alpha v-containing integrin are expressed and unassembled laminin and fibronectin are abundant around myogenic cells. At E13.5-E14.5, alpha6beta1 and alpha7beta1 are expressed, and a laminin matrix forms around individual myotubes. Thus, myogenic cells change their integrin expression pattern during the course of primary myogenesis in the mouse, suggesting different roles for fibronectin- and laminin-containing matrices in this process.
细胞通过受体与细胞外基质相互作用，其中最常见的是整合素家族的受体。我们（Cachaco等人，[2003]《发育》130:1659 - 1671）以及其他研究人员（Schwander等人，[2003]《发育细胞》4:673 - 685）已经证明β1整合素在小鼠原发性肌生成中发挥作用。然而，在此过程中体内与β1配对的α亚基是什么尚不清楚。在这里，我们确定了胚胎第（E）11.5 - E14.5天α亚基的表达模式。分化的肌节肌细胞表达所有研究的α亚基。随着躯干（E12.5）和四肢（E11.5 - E12.5）的肌肉块形成，层粘连蛋白受体α6β1和α7β1无法检测到，并且不存在组装好的层粘连蛋白基质。相反，α1β1、α4β1、α5β1以及一种含αv的整合素表达，并且未组装的层粘连蛋白和纤连蛋白在成肌细胞周围大量存在。在E13.5 - E14.5时，α6β1和α7β1表达，并且在单个肌管周围形成层粘连蛋白基质。因此，在小鼠原发性肌生成过程中，成肌细胞改变其整合素表达模式，这表明含纤连蛋白和层粘连蛋白的基质在此过程中具有不同作用。
