Department of Biological Function, Faculty of Science, Osaka City University, Sumiyoshi, Osaka, Japan.
Mech Dev. 2010 Jan-Feb;127(1-2):146-58. doi: 10.1016/j.mod.2009.09.005. Epub 2009 Sep 19.
Directional migration of primordial germ cells (PGCs) toward future gonads is a common feature in many animals. In zebrafish, mouse and chicken, SDF-1/CXCR4 chemokine signaling has been shown to have an important role in PGC migration. In Xenopus, SDF-1 is expressed in several regions in embryos including dorsal mesoderm, the target region that PGCs migrate to. CXCR4 is known to be expressed in PGCs. This relationship is consistent with that of more well-known animals. Here, we present experiments that examine whether chemokine signaling is involved in PGC migration of Xenopus. We investigate: (1) Whether injection of antisense morpholino oligos (MOs) for CXCR4 mRNA into vegetal blastomere containing the germ plasm or the precursor of PGCs disturbs the migration of PGCs? (2) Whether injection of exogenous CXCR4 mRNA together with MOs can restore the knockdown phenotype? (3) Whether the migratory behavior of PGCs is disturbed by the specific expression of mutant CXCR4 mRNA or SDF-1 mRNA in PGCs? We find that the knockdown of CXCR4 or the expression of mutant CXCR4 in PGCs leads to a decrease in the PGC number of the genital ridges, and that the ectopic expression of SDF-1 in PGCs leads to a decrease in the PGC number of the genital ridges and an increase in the ectopic PGC number. These results suggest that SDF-1/CXCR4 chemokine signaling is involved in the migration and survival or in the differentiation of PGCs in Xenopus.
原始生殖细胞(PGCs)向未来性腺的定向迁移是许多动物的共同特征。在斑马鱼、小鼠和鸡中,SDF-1/CXCR4 趋化因子信号已被证明在 PGC 迁移中具有重要作用。在非洲爪蟾中,SDF-1 在胚胎的几个区域表达,包括背中胚层,这是 PGC 迁移的目标区域。已知 CXCR4 在 PGC 中表达。这种关系与更为知名的动物一致。在这里,我们提出了实验来检验趋化因子信号是否参与了非洲爪蟾 PGC 的迁移。我们研究了:(1)向含有生殖质或 PGC 前体的植物半球胚泡注射 CXCR4 mRNA 的反义形态发生素寡核苷酸(MOs)是否会干扰 PGC 的迁移?(2) 注射外源性 CXCR4 mRNA 能否与 MOs 一起恢复敲低表型?(3) PGC 中特异表达突变型 CXCR4 mRNA 或 SDF-1 mRNA 是否会干扰 PGC 的迁移行为?我们发现,CXCR4 的敲低或 PGC 中突变型 CXCR4 的表达导致生殖嵴中 PGC 数量减少,而 PGC 中 SDF-1 的异位表达导致生殖嵴中 PGC 数量减少和异位 PGC 数量增加。这些结果表明,SDF-1/CXCR4 趋化因子信号参与了非洲爪蟾中 PGC 的迁移、存活或分化。