microRNA-9 multitasking near organizing centers

Abstract

A new study shows that microRNA-9 regulates multiple processes near the organizing centers during early brain development in zebrafish, revealing previously unknown modes of action for microRNAs in the nervous system.

Figure 1

The functions of miR-9 near the MHB. (a) miR-9 delimits the MHB through inhibition of fgf8 and fgfr1. The Fgf signaling pathway is highly active in the MHB (highlighted in green) and miR-9 is expressed in adjacent domains (highlighted in pink and orange) but not in the MHB. The bars above each gene indicate their expression domains. GOF, gain of function; LOF, loss of function. (b) Differential actions of miR-9 in zebrafish and Drosophila. In fish, miR-9 suppresses the expression of its anti-target her5 and its target her9, which are suppressors of neurogenesis. In fly, miR-9a downregulates Senseless (sens), whose high level of expression in the presumptive sensory organ precursors promotes the formation of neuronal precursors. In both cases, miR-9 expression avoids the progenitor pool.