Researcher(s)
- Olivia Cameron, Biological Sciences, University of Delaware
Faculty Mentor(s)
- Malcolm Arnott, Biological Sciences, University of Delaware
- Jia Song, Biological Sciences, University of Delaware
Abstract
MicroRNAs (miRNA) are small, non-coding RNAs that regulate numerous biological processes, including cell cycle progression and mitotic fidelity. miRNAs modulate gene expression by binding to target mRNAs to induce the degradation of mRNAs or inhibit translation. Using the sea urchin embryo as a model, we found miR-31 and its target transcripts (Fascin, Rab35, gelsolin, and β-actin) are enriched on the mitotic spindle. When miR-31 is inhibited, embryos display developmental delay and increased cytoskeletal and chromosomal defects. Prior experiments have demonstrated that miR-31 target localization at the spindle is critical for regulating RNAs that encode proteins involved in mitosis. Using Oligonucleotide-directed proximity interactome mapping (O-MAP), we identified proteins proximal to miR-31 target RNAs. These proteins include G3BP2, hnRNP-K, and Caprin-1. G3BP2 is a scaffold enzyme that has a role in forming stress granules; hnRNP-K is responsible for heterogeneous ribonucleoprotein formation, promotion and repression of translation as well as neuronal development and tumorigenesis; Caprin-1 forms stress granule and is involved in mRNA localization. We plan to examine the temporal and spatial expression of G3BP2, hnRNP-K, and Caprin-1 throughout embryogenesis using RNA in situ hybridization (ISH). G3BP2, hnRNP-K, and Caprin-1 sequences have been cloned from urchin cDNA into the zero-blunt vector, and transcribed into RNA probes to be used for ISH. My preliminary results indicate that Caprin-1 is ubiquitous and enriched on the mitotic spindle, and we will follow with hnRNP-K and G3BP2 to assay their expression. This research will provide insight into how miR-31 target mRNAs are transported to facilitate mitosis during early development.