Nitric oxide directly regulates gene expression during Drosophila development: need some gas to drive into metamorphosis?: Figure 1.

Abstract

Nitric oxide (NO) is an important second messenger involved in numerous biological processes, but how it regulates gene expression is not well understood. In this issue of Genes & Development, Cáceres and colleagues (pp. 1476–1485) report a critical requirement of NO as a direct regulator of gene expression through its binding to a heme-containing nuclear receptor in Drosophila. This may be an anciently evolved mechanism to coordinate behavior and metabolism during animal development.

Ecdysone triggered PGRP-LC expression controls Drosophila innate immunity

“…Consistent with this observation, Eip75B is known to repress some aspects of the 20E-induced regulatory network through its ability to heterodimerize and interfere with transcriptional activation mediated by another nuclear hormone receptor, HR46 (Thummel, 1997;White et al, 1997;Yamanaka and O'Connor, 2011). Interestingly, HR46 and Eip75B are homologs of ROR and Rev-Erb respectively, that regulate mammalian immune responses.…”

Direct effects of hypoxia and nitric oxide on ecdysone secretion by insect prothoracic glands

“…In Drosophila, the PG express high levels of NOS, and knockdown of NOS in the PG prolongs larval feeding, increases lipid storage, and blocks metamorphosis (Caceres et al, 2011). The pathway by which NO regulates the PG appears to be through bFTZ-F1, the insect homolog of the vertebrate steroidogenic factor 1, which regulates vertebrate steroidogenic enzyme transcription (Asahina et al, 2000;von Hofsten and Olsson, 2005;Yamanaka and O'Connor, 2011). The model whereby NO has been postulated to regulate steroid secretion in Drosophila is schematized in Fig.…”

“…Other recent studies in Drosophila have focused on the involvement of nitric oxide gas (NO) on PG function. NO is a product of nitric oxide synthase (NOS) and is a diffusible second messenger that influences a variety of cellular functions in vertebrates and invertebrates (Alderton et al, 2001;Davies, 2000;Koch et al, 1994;Yamanaka and O'Connor, 2011). In insects, NO has been implicated in the regulation of fluid production, cell proliferation, synapse formation, and innate immunity (Davies, 2000;Yamanaka and O'Connor, 2011).…”

The role of reduced oxygen in the developmental physiology of growth and metamorphosis initiation inDrosophila melanogaster

“…Finally, in mealworms, the duration of a juvenile instar is linearly correlated with atmospheric oxygen level (Greenberg and Ar, 1996). In addition, nitric oxide signaling (NOS) is known to be critical for metamorphosis initiation (Cáceres et al, 2011;Yamanaka and O'Connor, 2011). NO-mediated E75 inactivation in the prothoracic gland is necessary to promote ecdysteroidogenesis.…”

“…NO-mediated E75 inactivation in the prothoracic gland is necessary to promote ecdysteroidogenesis. NOS can be induced by low-oxygen conditions (Cáceres et al, 2011;Yamanaka and O'Connor, 2011). This provides a potential molecular mechanism by which declining internal oxygen levels might modulate ecdysteroidogenesis, and therefore growth rate and developmental transitions.…”