Garaulet, D.L., Castellanos, M.C., Bejarano, F., Sanfilippo, P., Tyler, D.M., Allan, D.W., Sánchez-Herrero, E., Lai, E.C. (2014). Homeotic Function of Drosophila Bithorax-Complex miRNAs Mediates Fertility by Restricting Multiple Hox Genes and TALE Cofactors in the CNS.  Dev. Cell 29(6): 635--648.

FBrf0225399

Research paper

The Drosophila Bithorax complex (BX-C) Hox cluster contains a bidirectionally transcribed miRNA locus, and a deletion mutant (Δmir) lays no eggs and is completely sterile. We show these miRNAs are expressed and active in distinct spatial registers along the anterior-posterior axis in the CNS. Δmir larvae derepress a network of direct homeobox gene targets in the posterior ventral nerve cord (VNC), including BX-C genes and their TALE cofactors. These are phenotypically critical targets, because sterility of Δmir mutants was substantially rescued by heterozygosity of these genes. The posterior VNC contains Ilp7+ oviduct motoneurons, whose innervation and morphology are defective in Δmir females, and substantially rescued by heterozygosity of Δmir targets, especially within the BX-C. Collectively, we reveal (1) critical roles for Hox miRNAs that determine segment-specific expression of homeotic genes, which are not masked by transcriptional regulation; and (2) that BX-C miRNAs are essential for neural patterning and reproductive behavior.

PMC4111139 (PMC) (EuropePMC)