Fujita Makiko, Itoh Mari, Shibata Mikihito, Taira Sumiko, Taira Masanori
Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.
Gene Expr Patterns. 2002 Nov;2(1-2):23-6. doi: 10.1016/s0925-4773(02)00348-9.
To study how epithelial layers are formed during early development in Xenopus embryos, we have focused on Claudin, the major component of the tight junction. So far, 19 claudin genes have been found in the mouse, expressed in different epithelial tissues. However, though a number of cytological studies have been done for the roles of Claudins, their expression patterns and functions during early embryogenesis are largely unknown. We found three novel Xenopus claudin genes, which are referred to as claudin-4L1, -4L2, and -7L1. At the early gastrula stage, claudin-4L1, -4L2, and -7L1 mRNAs were detected in the ectoderm and in the mesoderm. At the late gastrula stage, claudin mRNAs were detected in the ectoderm through the involuting archenteron roof. At the neurula stage, claudin-4L1/4L2 and -7L1 mRNAs were differentially expressed in the neural groove and the epidermal ectoderm. At the tailbud stage, the claudin mRNAs were found in the branchial arches, the otic vesicles, the sensorial layer of the epidermis, and along the dorsal midline of the neural tube. In addition, claudin-4L1/4L2 mRNAs were detected in the pronephros and the endoderm, whereas claudin-7L1 mRNA was observed in the epithelial layer of the epidermis.
为了研究非洲爪蟾胚胎早期发育过程中上皮层是如何形成的，我们聚焦于紧密连接的主要成分——闭合蛋白。到目前为止，已在小鼠中发现19个闭合蛋白基因，它们在不同的上皮组织中表达。然而，尽管已经针对闭合蛋白的作用开展了大量细胞学研究，但它们在早期胚胎发生过程中的表达模式和功能仍 largely未知。我们发现了三个新的非洲爪蟾闭合蛋白基因，分别称为闭合蛋白 - 4L1、-4L2和 - 7L1。在原肠胚早期阶段，在外胚层和中胚层中检测到闭合蛋白 - 4L1、-4L2和 - 7L1的mRNA。在原肠胚晚期阶段，通过内卷的原肠顶在外胚层中检测到闭合蛋白mRNA。在神经胚阶段，闭合蛋白 - 4L1/4L2和 - 7L1的mRNA在神经沟和表皮外胚层中差异表达。在尾芽阶段，在鳃弓、耳泡、表皮感觉层以及神经管背中线沿线发现了闭合蛋白mRNA。此外，在原肾和内胚层中检测到闭合蛋白 - 4L1/4L2的mRNA，而在表皮的上皮层中观察到闭合蛋白 - 7L1的mRNA。
