Meeting Abstract
Extensive work has characterized the heart gene regulatory network for invertebrate chordate, Ciona intestinalis. Ciona is used for studying developmental gene regulation due to shared characteristics with vertebrates in initial cardiac development, along with its smaller and more accessible genome. We have recently sequenced the genome of a related species Corella inflata in order to investigate the evolution of gene regulatory networks. Previous computational analysis indicates that the FoxF heart lineage enhancer is highly conserved in sequence and organization of binding sites across Ciona and Corella. However, the evolution of other cardiac developmental enhancers in Ciona and Corella remains largely uncharacterized. Here we show that the Corella Hand-like enhancer is less strictly conserved than FoxF. Specifically, transcription factor binding sites in the Hand-like enhancer are conserved, but their orientation and distribution have diverged. This indicates that the selective evolutionary pressures exerted on different regulatory nodes in a developmental gene network may differ in intensity. Our results provide insight into the complexity of chordate enhancer sequence evolution. Our continuing analysis of the Hand-like enhancer will provide a valuable framework for future comparative analysis.
