Meeting Abstract

33.5  Friday, Jan. 4  Gone with the Wnts: Genomic insights into Wnt signaling in the ctenophore, Pleurobrachia bachei BRUDERS, R*; KOHN, A.B.; KOCOT, K.M.; SWALLA, B.J.; NOREKIAN, T; MOROZ, L.L.; Univ of Washington; Univ of Florida; Auburn Univ; Univ of Washington; Univ of Florida; Univ of Florida rebeccabruders@gmail.com

Wnt signaling is known to be critical for proper embryonic development in most animals studied to date. Still, a key evolutionary question involves the origin and evolution of this pathway in the last common ancestor of metazoan. Recently, the genome of Pleurobrachia bachei, a member of the early branching metazoan linage Ctenophora, has been sequenced. Insights into the function of the Wnt pathway in P. bachei will provide information on early evolution of this key pathway. First, only three Wnt ligand genes (PbWnt6, PbWnt9, and PbWntX) were identified and cloned in P. bachei compared the ctenophore Mnemiopsis leidyi which has 4 Wnt ligand genes. Second, using in situ hybridization these genes showed differential expression in the combs, tentacles, mouth, ciliated grooves and polar fields of the adult P. bachei. However, surprisingly there were very low levels of expression in all the Wnt ligands in the P. bachei embryos. A genomic survey for other members of the canonical Wnt pathway revealed components of the destruction complex and antagonists were incomplete or missing from the genome as was also in Mnemiopsis. The extensive expression of Wnt ligands in the adult P. bachei indicates that Wnt could also be playing a role in neurotransmission in the adult.