title: The mode and molecular mechanisms of the migration of presumptive PGC in the endoderm cell mass of Xenopus embryos.
abstract: We investigated the mode of migration of presumptive primordial germ cells (pPGC) in the endoderm cell mass of Xenopus embryos at stages 7-40. The molecules underlying the migration were also studied cytochemically and immunocytologically. By examining the relative positions of pPGC and somatic cells derived from the single, fluorescein-dextran lysine (FDL)-injected, germ plasm-bearing cells of stage 6 embryos, pPGC in embryos at stages 7-23 and those at stages later than 24 were assumed to passively and actively migrate in the endoderm cell mass, respectively. This assumption was supported by the observation that F-actin, essential for active cell migration, was recognized on pPGC of the latter stages, but never on those of the former ones. In addition, the molecule like CXC chemokine receptor 4 (CXCR4) found on directionally migrating PGC in mouse and zebrafish, probably Xenopus CXCR4 (xCXCR4), was detected on pPGC only at latter stages. Accordingly, F-actin and xCXCR4, and probably beta1-integrin and collagen type IV, which are indispensable for the formation of F-actin, are thought to be involved in the active migration of pPGC in the endoderm cell mass.
authors.affiliation: Department of Biology, Graduate School of Science, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi, Osaka 558-8585, Japan.
authors.forename: Fumiko
authors.initials: F
authors.lastname: Nishiumi
authors.forename: Tohru
authors.initials: T
authors.lastname: Komiya
authors.forename: Kohji
authors.initials: K
authors.lastname: Ikenishi
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002465:Cell Movement / Q000502:physiology*; D002846:Chromatography, Affinity; D017931:DNA Primers; D004625:Embryo, Nonmammalian / Q000378:metabolism / Q000502:physiology; D004707:Endoderm / Q000502:physiology*; D005854:Germ Cells / Q000378:metabolism / Q000502:physiology*; D007150:Immunohistochemistry; D019718:Receptors, CXCR4 / Q000378:metabolism; D014981:Xenopus / Q000196:embryology*
chemical_list: D000199:Actins; D017931:DNA Primers; D019718:Receptors, CXCR4