Meeting Abstract

P3.77  Friday, Jan. 6  Knockdown of PaxB and Six1/2 by RNAi leads to developmental defects of the aquiferous system in the freshwater sponge Ephydatia muelleri WINTERS, Ian*; RUED, Anna; SIYU , Ding; POSFAI, Dora; GENTILE, Lisa; RIVERA, Ajna; HILL, April; University of Richmond; University of Richmond; University of Richmond; University of Richmond; University of Richmond; University of the Pacific; University of Richmond ahill2@richmond.edu

Sponges belong to an ancient metazoan lineage, and they represent an extant relic of the first experiment in animalian multicellularity. Thus, members of this phylum hold important clues about fundamental aspects of animal development. The genomes of sponges are remarkable because they possess an extensive set of animal-specific genes despite the lack of major animal traits (e.g., neurons, organ systems). Among these animal-specific genes, the demosponge genome is known to encode one Pax and one Six ortholog. Pax and Six genes are two members of a gene regulatory network, which regulates aspects of organogenesis (e.g., sensory organ, kidney). Here we examine the regulation and function of a Pax and Six gene in the freshwater sponge Ephydatia muelleri, an emerging model for behavioral and expression studies. We present data that: 1) Suggests PaxB and Six1/2 are involved in a regulatory network in Ephydatia muelleri which means that this network originated early in the Metazoa 2) Targeted knockdown of PaxB and Six1/2 affects endopinacoyte, choanocyte and oscula development in this species leading to defects of the aquiferous system.