Meeting Abstract

P1.84  Monday, Jan. 4  Evolution of the Wnt pathway, insights from the annelid Capitella teleta AMIEL, A.*; SEAVER, E.C.; Kewalo Marine Laboratory, Honolulu, Hawaii, USA; Kewalo Marine Laboratory, Honolulu, Hawaii, USA aamiel@hawaii.edu

The Wnt pathway is crucial for orchestrating a number of events during metazoan embryogenesis, from early cleavage stages to tissue differentiation. Wnt genes are well conserved from cnidarians to vertebrates, and it is likely that they have important conserved developmental roles. The complexity of the Wnt pathway leaves a number of unresolved questions and current models are insufficient to explain the complex responses often observed in developing organisms. Within spiralians, investigations of the role of the intracellular mediator of the canonical Wnt pathway, β-catenin, have revealed substantial species-specific differences during early development. For example, in the nemertean Cerebratulus, β-catenin functions as an important factor in determining vegetal embryonic fates, and later in tissue layer formation. In contrast, in the annelid Platynereis, β-catenin functions in binary cell fate specification. In this study, we focus on Capitella teleta, a well-suited polychaete model to study developmental biology. Compared to some other protostomes, lophotrochozoan genomes appear to have retained a large complement of wnt gene subfamilies. In the C. teleta genome, there are 12 Wnt ligands, representing 12 of the 13 established subfamilies. Expression analysis of 5 Wnt ligands reveals distinct patterns during larval stages, suggesting diverse roles for each Wnt gene. We are currently focusing on characterizing expression and roles of the Wnt pathway members during early cleavage stages to understand the integration of signaling pathways during early development, which is generally not well understood in spiralians. Our results contribute to an understanding of the variation of early developmental roles of this signaling pathway has in different spiralian species.