title: Gene expression pattern analysis of the tight junction protein, Claudin, in the early morphogenesis of Xenopus embryos.
abstract: 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.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Makiko
authors.initials: M
authors.lastname: Fujita
authors.forename: Mari
authors.initials: M
authors.lastname: Itoh
authors.forename: Mikihito
authors.initials: M
authors.lastname: Shibata
authors.forename: Sumiko
authors.initials: S
authors.lastname: Taira
authors.forename: Masanori
authors.initials: M
authors.lastname: Taira
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D062506:Claudin-4; D057167:Claudins; D004475:Ectoderm / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000378:metabolism*; D020869:Gene Expression Profiling; D017403:In Situ Hybridization; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D014981:Xenopus; D029867:Xenopus Proteins
chemical_list: D062506:Claudin-4; D057167:Claudins; C568158:Cldn4 protein, mouse; D008565:Membrane Proteins; D029867:Xenopus Proteins; C422906:claudin protein, Xenopus