Meeting Abstract

76.2  Monday, Jan. 6 08:15  Functional conservation of heart-related enhancers in Ciona intestinalis and Corella inflata HWANG, A.E.*; DAVIDSON, B.J.; Swarthmore College; Swarthmore College ahwang2@swarthmore.edu

Cis-regulatory elements (CREs) are responsible for regulating the timing and localization of gene expression. Orthologous CREs from widely disparate species can display conserved regulatory activity despite significant sequence variation. To investigate the evolutionary implications of robust regulatory elements, we have begun to explore functional conservation of heart lineage enhancers between two distantly related tunicate species, Ciona intestinalis and Corella inflata. Using characterized Ciona enhancers, we visualized reporter activity in Corella embryos with beta-galactosidase and immunofluorescent staining. Nearly all of the tested enhancers drove conserved patterns of reporter gene expression in Corella. Additionally, treatment of Corella embryos with the MEK inhibitor U0126 blocked the migration of the heart progenitor cells, indicating that the FGF/Map Kinase dependent induction of progenitor migration, as characterized in Ciona, is conserved in Corella. Our findings suggest that the regulatory network underlying heart progenitor specification may be functionally conserved between these species. We plan to further explore relationships between CRE function and architecture in the development of the tunicate heart and the role that enhancer evolution might play in key morphological changes, such as heart progenitor cell migration and post-larval heart formation.