Meeting Abstract
99.2 Monday, Jan. 6 13:45 miRNAs in hemichordate development GRAY, J.*; FREEMAN, JR. , R.M.; GERHART, J.; KIRSCHNER, M.W.; Harvard Medical School; Harvard Medical School; University of California, Berkeley; Harvard Medical School jessica_gray@hms.harvard.edu
miRNAs act as post-transcriptional regulators of gene expression networks in a number of developmental processes, and multiple evolutionary expansions of miRNAs are associated with body plan innovations. However, despite growing evidence for the role of miRNAs in model organism development and genome-wide small RNA studies in numerous species, data is lacking for a functional role of miRNAs in the development of non-model organisms. The question remains whether the evolution of targets and functions of miRNAs might have driven the evolution of developmental pathways or if they are instead uniquely regulated in different lineages. We are investigating the developmental expression and function of microRNAs in the direct-developing hemichordate Saccoglossus kowalevskii. As deuterostomes, hemichordates and vertebrates share a common ancestor and many developmental signaling pathways, making Saccoglossus an ideal model for uncovering how ancestral miRNAs may have contributed to evolution of development in the deuterostome lineage. Small RNA sequencing revealed that Saccoglossus miRNAs are dynamically expressed throughout development, suggesting potential roles in a number of developmental processes. An initial functional screen based upon these sequencing results has confirmed a conserved role for miR-1 in muscle development and revealed a potentially novel role for the neural miRNA miR-124 in dorsal/ventral patterning. The targets and functions of both conserved and non-conserved Saccoglossus miRNAs will be compared with their homologs and functional counterparts in vertebrates. Our work provides a first exploration of miRNA function in hemichordate development, which will contribute to understanding how the role of miRNA regulation in development has changed through evolution.
