Vasa protein expression and localization in the zebrafish

Primordial germ cell (PGC) development in the zebrafish is poorly understoo d. The expression of vasa RNA, the only molecular marker so far found to be expressed in fish PGCs, suggests its function in the establishment of the germline. The protein product of vasa is present throughout the life cycle in the germline of Drosophila, Caenorhabditis and Xenopus. The expression p attern of the Vasa protein in zebrafish, is still unresolved. We generated an anti-Vasa polyclonal antibody and show that it is maternally expressed i nitially throughout the embryo. Interestingly, from the two-cell- to the 10 00-cell stage the protein is highly concentrated in two 'dots' near the cen ter of the blastomeres and as such remains longest detectable in the animal pole blastomeres. The first distinct cell-specific expression occurs at 60 % epiboly on one side of the blastoderm margin. The Vasa protein in the PGC s is organized in a subcellular granular-like conformation which is dynamic throughout development. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.