Roles of miRNAs During Early Zebrafish Development

Abstract

microRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at the post-transcriptional level by specific binding to recognition elements in the 3’ untranslated regions (UTRs) of target mRNAs. In zebrafish embryonic development, miRNAs coordinately interact with many target transcripts to fin-tune overall gene expression. However, their expression profiles and critical functions during early zebrafish development remain to be elucidated. In order to understand miRNA expression and function, I first characterized the temporal expression of all miRNAs during very early zebrafish embryonic development using high-throughput sequencing and identified 8 novel miRNAs. I also identified an unexpected abundance of piRNAs during early developmental. To analyze specific targets and understand the rationale for miRNA regulation, I focused on mRNA targets for miR-153 and miR-27. I show that miR-153 regulates snap25 during synaptic transmission and motor neuron development. In addition, I also show that miR-27 targets ptk2.2 to regulate pharyngeal arch morphogenesis.