Meeting Abstract
P1.94 Saturday, Jan. 4 15:30 Investigating the cis-regulation of the cnidarian endomesoderm GRN WIJESENA, N*; SIMMONS, D; ROTTINGER, E; MARTINDALE, M.Q.; Whitney Laboratory of Marine Bioscience; Whitney Laboratory of Marine Bioscience; Institute for Research on Cancer and Aging, Nice, France; Whitney Laboratory of Marine Bioscience naveenw@whitney.ufl.edu
A characteristic feature of metazoan development is the formation of distinct germ layers that subsequently differentiate in to specialized adult tissues. The fate of the cells that gives rise to these different germ layers is determined by the transcriptional activators/repressors whose activity is governed by the inputs of intracellular and/or extracellular signals. Canonical Wnt/ß-catenin (cWnt) pathway provides crucial inputs during germ layer specification in metazoans. A recent study in the basal metazoan Nematostella vectensis has characterized the NvTcf/cWnt signaling inputs in to this cnidarian endomesodermal gene regulatory network (GRN). A detailed understanding of transcriptional control by inputs of NvTCF/cWnt during mesendoderm formation requires a cis-regulatory analysis of key genes in the network to identify transcription factor binding sites. We have used a combination of experimental and bioinformatic (phylogenetic footprinting using the Acropora digitifera genome) approaches to isolate the cis-regulatory modules controlling the expression of two genes in the endomesodermal GRN, NvFrizzled10 and NvStrabismus. Genomic DNA fragments upstream of the start codon of both these genes were cloned into a transgenesis vector driving the expression of the reporter protein mCherry. Injecting these constructs in to zygotes results in the transient expression of mCherry in developing embryos. The functional importance of these identified sites will be validated by generating mutagenized cis-regulatory sequences and testing their activity by transient transgenesis assays. This approach will provide critical information for a detailed understanding of the architecture of the Nematostella endomesodermal GRN.
