The transcription factor Grainy head and the steroid hormone ecdysone cooperate during differentiation of the skin of Drosophila melanogaster

Abstract

The arthropod epidermis is an epithelium that deposits the apical cuticle, which is a stratified extracellular matrix (ECM) protecting the animal against pathogens, preventing dehydration and also serving as an exoskeleton. Differentiation of the cuticle conceivably implies coordinated production, secretion and localization of its components. The underlying molecular mechanisms are poorly explored. In this work, we show that the transcription factor Grainy head and the steroid hormone ecdysone drive the production of two partially overlapping sets of cuticle factors. Nevertheless, Grainy head is needed to modulate the expression of ecdysone signalling factors; the significance of this cross-talk is yet unclear. In addition, we found that ecdysone signalling negatively regulates its own impact. In conclusion, our findings suggest that at least two independently triggered pathways have evolved in parallel to cooperatively ensure the stereotypic implementation of the cuticle. As Grainy head is also essential for epithelial differentiation in vertebrates, we speculate that it acts to decode the ancient skin programme common to all animals. Full differentiation of the skin necessitates a second, complementing taxon-specific programme that requires its own decoder, which is represented by ecdysone in arthropods, whereas the vertebrate specific one remains to be identified.

Silencing chitin deacetylase 2 impairs larval–pupal and pupal–adult molts in Leptinotarsa decemlineata

“…Consistent with the hypothesis proposed by Yu et al . (), mutation in vermiform ( verm , CDA2 ) in the common fruit fly Drosophila melanogaster leads to elongated and tortuous tracheal tubes (Luschnig et al ., ; Wang et al ., ) and results in disorganized larval cuticle (Gangishetti et al ., ). Moreover, RNAi of CDA2 in the eastern spruce budworm Choristoneura fumiferana (Quan et al ., ), the brown planthopper Nilaparvata lugens (Xi et al ., ), and the red flour beetle Tribolium castaneum (Arakane et al ., ) causes molting failure.…”

Integrin Adhesions Suppress Syncytium Formation in the Drosophila Larval Epidermis

“…After DC is completed, larval epidermal cells secrete apical cuticle [11] to accompany the basal lamina assembled during embryogenesis [12]. In the epidermal plane these endoreduplicated cells [13] pack into a highly regular sheet [10].…”

Conserved Transcription Factors Steer Growth-Related Genomic Programs in Daphnia

“…The curated network contains genes involved in trichome formation, developmental timing and cuticle formation. References to fruit fly literature: 1) Yoshiyama et al (2006); 2) Gauhar et al (2009); 3) Agawa et al (2007); 4) White et al (1997); 5) Chanut-Delalande et al (2014); 6) Kondo et al (2010); 7) Menoret et al (2013); 8) Lee and Adler (2004); 9) Gangishetti et al (2012); 10) Jang et al (2009); 11) Ono et al (2006). ( B ) The heatmap demonstrates coexpression of the genes in the network.…”

“…In Drosophila , Grh is involved in adult epidermis differentiation (Lee and Adler 2004), cuticle organization (Gangishetti et al 2012) and wound healing (Mace et al 2005), and functions together with Svb (Menoret et al 2013). The signal triggering the expression of this factor in insects is still unknown (Gangishetti et al 2012). We found NR motifs in the promoter sequence of grh , indicating that in D. magna , grh is potentially regulated by one or several NRs of the ecdysone-signaling cascade.…”