A class of small RNAs, called microRNAs (miRNAs), has recently been discovered and has been shown to regulate gene expression by binding to the untranslated regions of transcribed genes leading to degradation and/or repression of protein formation. Much remains to be discovered of exactly how these miRNAs function, and consequently very little is known about the importance of miRNA regulation to development and the generation of morphology. MiRNAs evolve rapidly compared to coding genes and they may also acquire and lose targets more rapidly so that they could provide a source of significant variation during evolution. This project will use a variety of molecular and computational approaches to examine the functional role of miRNAs in the sea urchin Strongylocentrotus purpuratus, which was chosen for this study because it has an extremely well characterized gene regulatory network for early development. It will also be determined how this regulation may have evolved, and what developmental consequences this may have, by testing whether miRNAs regulate similar genes in other echinoderms, specifically in the closely related sea urchin Lytechinus variegatus and the distantly related sea star Asterina miniata. A great deal is known of how transcription factor based gene regulatory networks have evolved between the sea star and sea urchins and the consequences of this for their development. It is anticipated that this project will reveal how miRNA regulation can control development and how it changes over evolutionary time in the context of a gene regulatory network. Several women graduate and undergraduate students will be trained in a variety of experimental and computational techniques. Also the PI and graduate students in the PI's lab will run a short lab and lecture course at Ringold High School to introduce these students to the concepts of computational and developmental biology.
