Spatiotemporal expression of miR-1 target transcripts during sea urchin development

• Ariana Ali, Biological Sciences, University of Delaware

• Jia Song, Biological Sciences, University of Delaware

Following fertilization, the embryo undergoes rapid mitotic cell divisions that require precise regulation. Flaws in this process can negatively affect embryonic development and health. MicroRNAs (miRNA) are short non-coding RNAs known to regulate gene expression through translational repression or degradation of mRNA transcripts. miR-1 is an evolutionary conserved microRNA that is known to regulate cardiovascular development and skeletal muscle differentiation. miR-1 was found by our lab to regulate genes important for proper chromosomal segregation and spindle formation, including Cdc42 and NuMA. To discover additional functions of miR-1 during early development, we used quantitative, comparative proteomics in miR-1 overexpressed and inhibited embryos. Preliminary results indicate miR-1 may regulate genes that encode proteins involved in mitosis (Tubulin alpha-1 chain; Ta-1C), mitochondrial metabolism (Ndufs4), and cell motility (outer dense fiber protein 3; ODF3). The goal of this study is to determine the temporal and spatial expression of potential miR-1 target transcripts throughout development. Ta-1C assists in forming microtubules in the mitotic spindle complex. Ndufs4 is a subunit in Complex I of the mitochondrial electron transport chain. ODF3 encodes fiber proteins necessary for sperm motility. Preliminary work indicates that Ta-1C is expressed in mesodermal and endodermal cells during the blastula and gastrula stages, while it is expressed in the midgut of the larval stage. We are working on determining Ndufs4 and ODF3 expression patterns. Future studies will validate Ndufs4 and Ta-1C as direct targets of miR-1. This work provides insight into miR-1’s regulation in early developmental stages.