The International Journal of Developmental Biology

Int. J. Dev. Biol. 49: 843 - 850 (2005)

Vol 49, Issue 7

The formation of primordial germ cells from germline cells in spherical embryos derived from the blastodisc of 2-cell embryos in goldfish, Carassius auratus

Open Access | Original Article | Published: 1 September 2005

Satoshi Otani1,4, Tomoe Kitauchi2, Taiju Saito1, Suzu Sakao1, Shingo Maegawa3, Kunio Inoue3, Katsutoshi Arai1 and Etsuro Yamaha*,2,4

1Laboratory of Breeding Science, 2Laboratory of Cellular Information Science, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Japan, 3Molecular and Developmental Biology, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Japan and 4Nanae Fresh Water Laboratory, Field Science Center for Northern Biosphere, Hokkaido University, Nanae, Japan


The property of primordial germ cells (PGCs) in fragmented goldfish embryos was investigated. When 1- and 2- cell embryos were cut at several perpendicular levels at the animal-vegetal axis, cells expressing vas mRNA were observed in the resultant embryos derived from all kinds of animal fragments. Blastodisc fragments from the 1- to 2-cell stage developed to spherical embryos containing yolk body with a yolk syncytial layer (YSL). Germ ring and no tail expression were not observed in the spherical embryo. When the spherical embryo labeled with tracer dye or GFP-nos1 3'UTR mRNA was transplanted onto the animal part of the blastoderm in a host embryo at the blastula stage, PGCs of spherical embryo origin were detected around the gonadal ridges in the resultant embryos which developed normally. These results suggest that small animal fragments should contain factors sufficient for PGC differentiation and that PGCs differentiate without mesoderm induction, since mesoderm is not induced in a spherical embryo.


goldfish, PGCs, vas, nanos, maternal cytoplasmic component

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