A zebrafish nanos-related gene is essential for the development of primordial germ cells

Asymmetrically distributed cytoplasmic determinants collectively termed germ plasm have been shown to play an essential role in the development of primordial germ cells (PGCs). Here, we report the identification of a nanos-like (nanos1) gene, which is expressed in the germ plasm and in the PGCs of the zebrafish. We find that several mechanisms act in concert to restrict the activity of Nanos1 to the germ cells including RNA localization and control over the stability and translatability of the RNA. Reducing the level of Nanos1 in zebrafish embryos revealed an essential role for the protein in ensuring proper migration and survival of PGCs in this vertebrate model organism.

Applications of Confocal Microscopy to Study the Roles of the Cytoskeleton During Early Embryogenesis In Amphibians

Because of their great size, availability, and capacity to develop autonomously in culture, amphibian eggs have become a productive system for a wide variety of experimental studies of animal cells. Their use has advanced our understanding of fundamental molecular and cellular processes such as transcription and translation, regulation of the cell cycle, and the function of the cytoskeleton. The amphibian egg, particularly that of the frog Xenopus laevis,has further served as an excellent system for studying complex developmental phenomena, including the roles of growth factors, signal transduction, and transcription regulation in cell determination, morphogenesis, and tissue differentiation.Despite these advantages, the frog egg's great size and opacity have made it a challenging subject for microscopy. Thus, many problems in early development, such as how maternal cytoplasmic determinants become localized during cell division, have resisted traditional optical approaches.