title: Medaka vasa is required for migration but not survival of primordial germ cells.
abstract: Vasa is essential for germline development. However, the precise processes in which vasa involves vary considerably in diverse animal phyla. Here we show that vasa is required for primordial germ cell (PGC) migration in the medakafish. vasa knockdown by two morpholinos led to the PGC migration defect that was rescued by coinjection of vasa RNA. Interestingly, vasa knockdown did not alter the PGC number, identity, proliferation and motility even at ectopic locations. We established a cell culture system for tracing PGCs at the single cell level in vitro. In this culture system, control and morpholino-injected gastrulae produced the same PGC number and the same time course of PGC survival. Importantly, vasa-depleted PGCs in culture had similar motility and locomotion to normal PGCs. Expression patterns of wt1a, sdf1b and cxcr4b in migratory tissues remained unchanged by vasa knockdown. By chimera formation we show that PGCs from vasa-depleted blastulae failed to migrate properly in the normal environment, whereas control PGCs migrated normally in vasa-disrupted embryos. Furthermore, ectopic PGCs in vasa-depleted embryos also retained all the PGC properties examined. Taken together, medaka vasa is cell-autonomously required for PGC migration, but dispensable to PGC proliferation, motility, identity and survival.
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Center for Developmental Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Wuhan, China.
authors.forename: Mingyou
authors.initials: M
authors.lastname: Li
authors.forename: Ni
authors.initials: N
authors.lastname: Hong
authors.forename: Hongyan
authors.initials: H
authors.lastname: Xu
authors.forename: Meisheng
authors.initials: M
authors.lastname: Yi
authors.forename: Changming
authors.initials: C
authors.lastname: Li
authors.forename: Jianfang
authors.initials: J
authors.lastname: Gui
authors.forename: Yunhan
authors.initials: Y
authors.lastname: Hong
mesh_terms: D000818:Animals; D001483:Base Sequence; D002465:Cell Movement / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D053487:DEAD-box RNA Helicases / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D055785:Gene Knockdown Techniques; D005854:Germ Cells / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D008954:Models, Biological; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000494:pharmacology; D009990:Oryzias / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype
chemical_list: D016376:Oligonucleotides, Antisense; D053487:DEAD-box RNA Helicases