Meeting Abstract
The basal chordate Ciona intestinalis has been used to untangle the chordate heart gene regulatory network, because of its rapid development and compact genome. A core set of transcription factors including Mesp, FoxF, Hand-like, and GATAa specify heart fate in Ciona. The enhancers for these heart genes are characterized, but little is known about the evolution of the heart gene regulatory network. Here we characterize conserved enhancers for FoxF and Hand-like using the Corella inflate genome, which we have recently sequenced. Computational analysis reveled conserved binding sites for upstream transcription factors in both enhancers, however the order, spacing, and orientation was more highly conserved in FoxF. Reporter analysis demonstrated that these Corella heart enhancers were functional in both Ciona and Corella. Our results support evolutionary conservation of the Ciona heart gene regulatory network and suggest more selective constraint on FoxF regulation. This work also provides a framework for the identification of novel Ciona heart enhancers based on clustering of conserved transcription factor binding sites.
