Developmental Regulation of Locomotive Activity in Xenopus Primordial Germ Cells

Dev Growth Differ. 2013 Feb;55(2):217-28. doi: 10.1111/dgd.12018. Epub 2012 Dec 20.

Abstract

Primordial germ cells (PGCs) arise in the early embryo and migrate toward the future gonad through species-specific pathways. They are assumed to change their migration properties dependent on their own genetic program and/or environmental cues, though information concerning the developmental change in PGC motility is limited. First, we re-examined the distribution of PGCs in the endodermal region of Xenopus embryos at various stages by using an antibody against Xenopus Daz-like protein, and found four stages of migration, namely clustering, dispersing, directionally migrating and re-aggregating. Next, we isolated living PGCs at each stage and directly examined their morphology and locomotive activity in cell cultures. PGCs at the clustering stage were round in shape with small blebs and showed little motility. PGCs in both the dispersing and the directionally migrating stages alternated between the locomotive phase with an elongated morphology and the pausing phase with a rugged morphology. The locomotive activity of the elongated PGCs was accompanied by the persistent formation of a large bleb at the leading front. The duration of the locomotive phase was shortened gradually with the transition from the dispersing stage to the directionally migrating stage. At the re-aggregating stage, PGCs became round in shape and showed no motility. Thus, we directly showed that the locomotive activity of PGCs changes dynamically depending upon the migrating stage. We also showed that the locomotion and blebbing of the PGCs required F-actin, myosin II activity and RhoA/Rho-associated protein kinase (ROCK) signaling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Animals
  • Cell Movement*
  • Cell Shape
  • Cells, Cultured
  • Ectoderm / cytology
  • Ectoderm / embryology
  • Ectoderm / metabolism
  • Embryo, Nonmammalian / cytology*
  • Embryo, Nonmammalian / embryology
  • Embryo, Nonmammalian / metabolism
  • Endoderm / cytology
  • Endoderm / embryology
  • Endoderm / metabolism
  • Germ Cells / cytology*
  • Germ Cells / metabolism
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Microscopy, Confocal
  • Myosin Type II / metabolism
  • Signal Transduction
  • Time Factors
  • Time-Lapse Imaging / methods
  • Xenopus Proteins / metabolism
  • Xenopus laevis / embryology*
  • rho-Associated Kinases / metabolism

Substances

  • Actins
  • Luminescent Proteins
  • Xenopus Proteins
  • rho-Associated Kinases
  • Myosin Type II