A Differential Transcriptomic Approach to Compare Target Genes of Homologous Transcription Factors in Echinoderm Species

Embryonic development is controlled by differential gene expression throughout developmental time. The ParaHox genes, Cdx and Xlox have been shown to be involved in the formation of the properly functioning gut in the sea urchin Strongylocentrotus purpuratus and the sea star Patiria miniata. Several genes involved in the gene regulatory network (GRN) are known, however, the network is still incomplete. With the current state of sequencing technology, we are now able to expand the network and gain further insight into the process of gut development on a more global scale. Through the use of high-throughput sequencing technology and knockdown experiments we have further characterized the effects of Cdx and Xlox on the GRN involved in gut development at different developmental stages. Additionally, we have conducted a cross-species comparison to identify genes that are more likely to be evolutionarily important for the development of the echinoderm gut. Within those genes we found a number of transcription factors that could potentially have important roles in the formation of the echinoderm gut. Using both RNA-seq and gene homology, we have set the foundation for further studies of echinoderm gut and the ParaHox GRN downstream of Xlox and Cdx.