MicroRNA-dependent regulation of Hox gene expression sculpts fine-grain morphological patterns in a appendage.

Disruptions of normal Hox gene expression can lead to severe morphological defects, revealing a link between the regulation of Hox expression and pattern formation. Here, we explore these links, focusing on the impact of microRNA regulation on the expression of the Hox gene () during haltere development. Through a combination of bioinformatic and transcriptomic analyses, we identify the miR-310/313 cluster () as a candidate regulator of Several experiments confirm this. First, and Ubx protein show complementary expression patterns in haltere imaginal discs; second, artificial activation of expression in haltere discs leads to -like phenotypes. Third, expression of a fluorescent reporter bearing 3'UTR sequences is reduced when co-expressed with Fourth, deletion of leads to upregulation and changes the array of mechanosensory sensilla at the base of the haltere. Fifth, an artificial increase of levels within the expression domain phenocopies the mechanosensory defects observed in mutants. We propose that -mediated repression delimits fine-grain expression, contributing to the sculpting of complex morphologies in the haltere with implications for flight control. Our work reveals a novel role of microRNA regulation in the control of Hox gene expression with impact on morphology.