Meeting Abstract

S5.8  Monday, Jan. 5  Exploring the role of cell fate specification in chordate heart evolution. DAVIDSON, Brad*; SWEENEY, Sarah; ZHEN, Yisong; RAGKOUSI, Katerina; Univ. of Arizona; Univ. of Arizona; Univ. of Arizona; Univ. of Arizona bjd18@email.arizona.edu

Chordate heart evolution appears to involve a gradual increase in complexity; from the simple peristaltic tubes of basal chordates to the four-chambered hearts of amniotes. To better understand this process, we study heart development in the basal chordate Ciona intestinalis. We have previously shown that Fibroblast Growth Factor (FGF) signaling plays a crucial role in Ciona heart specification. Targeted manipulations of this specification event increase heart cell progenitor number. Surprisingly, this increase in progenitor cells can result in the emergence of a novel, functional two-compartment heart phenotype. To better understand this intriguing result, we are analyzing two interlinked roles for FGF in Ciona heart specification; regulation of cell polarity and gene expression. Our data indicates that FGF initially regulates cell polarity thereby refining the transcriptional response of cells to subsequent FGF signaling. This dual role for FGF may provide a robust yet flexible mechanism for cell fate specification.