Meeting Abstract

50-1  Friday, Jan. 5 10:15 – 10:30  Patterning the freshwater sponge aquiferous system: Wnt signaling and Pax networks HILL, AL*; HALL, C; RIVERA, A; POSFAI, D; RODRIGUEZ, M; GARCIA, J; HILL, April; Univ. of Richmond, Virginia; Univ. of Virginia; Univ. of the Pacific, Stockton, California; Duke Univ., Durham, North Carolina; Univ. of Richmond, Virginia; Univ. of Richmond, Virginia ahill2@richmond.edu http://biology.richmond.edu/faculty/ahill2/

Canonical and non-canonical Wnt signaling, as well as the Pax/Six gene network, are involved in pattering of the freshwater sponge aquiferous system. Here, we describe a regulatory connection between the demosponge Pax transcription factor and components of the Wnt signaling pathway, suggesting that regulation of Wnt signaling by Pax family members may predate the divergence of sponges. We also functionally demonstrate a further role for Wnt signaling in aquiferous system development, showing that a Secreted Frizzled Related Protein (SFRP) likely acts as a Wnt antagonist. Finally, we find that SFRP localizes to a subpopulation of mesenchymal stem cells (archeocytes with filipodia) in the sponge mesohyl and suggest a role for SFRP in initiating morphogenetic processes.