The Roles of Hox genes in the Corazonergic Neurons of Neuroblast7-3 Sublineage

Abstract

In Drosophila development, Hox genes determine the cell fate in a segment specific manner. Recent studies have shown that Hox genes have a part in causing programmed cell death in neurogenesis at the level of neuroectoderm. This study shed lights on the roles of Hox genes in the NB7-3 sublineages particularly in corazonergic neuronal cell fate specification and apoptosis. By observation of the Ubx and abd-A mutant, these two genes are promoting factor for corazonergic lineage. On the other hand, the overexpression of Abd-B which endogenously expressed in posterior region, PS10-14 caused the lack of corazonin neuron in anterior segment, while extra corazonin neurons in A7-A8 segments were detected in Abd-B loss-of-function mutant. This region is identical to the rescued cell when the programmed cell death was inhibited. This data suggest that Abd-B exerts the pro-apoptotic role in NB7-3 development during embryogenesis. To figure out the effect of altered corazonin neurons caused by Hox gene mutation, we additionally examined the ethanol sedation assay in adult flies. Along the level of corazonin expression, known as a stress regulator, the resistance to the ethanol induced sedation was distinct to sex. Specially, male showed more significant differences than female in the respect of corazonin expression.