Meeting Abstract
P1.95 Saturday, Jan. 4 15:30 Understanding animal polarity: Functional studies during early embryogenesis of the sea anemone Nematostella vectensis. SALINAS-SAAVEDRA, M*; MARTINDALE, MQ; University of Florida, Florida mssaavedra@whitney.ufl.edu
How germinal layers are specified during early development of non-bilaterian animals is unclear. In bilaterian animals, rearrangements of the egg’s cytoplasm and cortical domains polarize the embryo and direct proper partitioning of maternal determinants into distinct daughter cells often in relationship to a regular cleavage program. In some bilaterian animals, Lethal Giant Larvae (LGL) and PARtitioning-defective proteins (Par) are conserved components of cellular polarization during early embryogenesis. Par proteins and their role in establishing embryonic asymmetry have been widely studied in bilaterian development but not in more basally branching animals. Interestingly, the basally branching cnidarian sea anemone Nematostella vectensis shows a “random” cleavage pattern and it undergoes gastrulation at the animal (not vegetal) pole of the egg; begging the question of whether the same molecular mechanisms are conserved for specifying the site of gastrulation. We address this question by characterizing the localization and function of different components of the Par complex during early development of the sea anemone N. vectensis. The mRNAs of Par proteins are asymmetrically localized. However, Immunostaining using antibodies made against NvLGL and NvaPKC shows that these proteins distribute throughout the egg and embryo without any clear polarization confirming results obtained when we over expressed them using mRNA injections. In addition, the over expression of the full length and dominant negative version of some Par proteins affect cleavage divisions and gastrulation but do not have a clear effect on embryonic polarity. These data will provide a glimpse into the evolution of cell polarity and the organization of metazoan embryonic germ layer formation.
