Downregulation of the Host Gene jigr1 by miR-92 Is Essential for Neuroblast Self-Renewal in Drosophila.

• Main Authors: Yeliz Yuva-Aydemir, Xia-Lian Xu, Ozkan Aydemir, Eduardo Gascon, Serkan Sayin, Wenke Zhou, Yang Hong, Fen-Biao Gao
• Format: Article
• Language: English
• Published: Public Library of Science (PLoS) 2015-05-01
• Series: PLoS Genetics
• Online Access: http://europepmc.org/articles/PMC4441384?pdf=render

Intragenic microRNAs (miRNAs), located mostly in the introns of protein-coding genes, are often co-expressed with their host mRNAs. However, their functional interaction in development is largely unknown. Here we show that in Drosophila, miR-92a and miR-92b are embedded in the intron and 3'UTR of jigr1, respectively, and co-expressed with some jigr1 isoforms. miR-92a and miR-92b are highly expressed in neuroblasts of larval brain where Jigr1 expression is low. Genetic deletion of both miR-92a and miR-92b demonstrates an essential cell-autonomous role for these miRNAs in maintaining neuroblast self-renewal through inhibiting premature differentiation. We also show that miR-92a and miR-92b directly target jigr1 in vivo and that some phenotypes due to the absence of these miRNAs are partially rescued by reducing the level of jigr1. These results reveal a novel function of the miR-92 family in Drosophila neuroblasts and provide another example that local negative feedback regulation of host genes by intragenic miRNAs is essential for animal development.