Chitinase 10 controls chitin amounts and organization in the wing cuticle of Drosophila

Abstract

Wings are essential for insect fitness. A number of proteins and enzymes have been identified to be involved in wing terminal differentiation, which is characterized by the formation of the wing cuticle. Here, we addressed the question whether chitinase 10 (Cht10) may play an important role in chitin organization in the wings of the fruit fly Drosophila melanogaster. Initially, we first found that Cht10 expression coincides with the expression of the chitin synthase coding gene kkv. This suggests that the respective proteins may cooperate during wing differentiation. In tissue-specific RNA interference experiments, we demonstrate that suppression of Cht10 causes an excess in chitin amounts in the wing cuticle. Chitin organization is severely disrupted in these wings. Based on these data, we hypothesize that Cht10 restricts chitin amounts produced by Kkv in order to ensure normal chitin organization and wing cuticle formation. In addition, we found by scanning electron microscopy that Cht10 suppression also affects the cuticle surface. In turn, cuticle inward permeability is enhanced in Cht10-less wings. Moreover, flies with reduced Cht10 function are unable to fly. In conclusion, Cht10 is essential for wing terminal differentiation and function.

Characterization and functional analysis of chitinase family genes involved in nymph–adult transition of Sogatella furcifera

“…In a recent study, Dong et al . (2020) showed that Cht10 is involved in regulating the morphology and function of the D . melanogaster wing cuticle, which in turn affects its flying ability.…”

“…In this study, SfCht10 silencing also induced phenotypic defects and high mortality during nymph-adult transition of S. furcifera, which indicates that SfCht10 is essential for nymph-adult transition of S. furcifera. In a recent study, Dong et al (2020) showed that Cht10 is involved in regulating the morphol-ogy and function of the D. melanogaster wing cuticle, which in turn affects its flying ability. In S. furcifera, we found that, when SfCht10 was suppressed by RNAi, the lethal rate at 96 h was 77% in the nymph stage and the surviving 23% of insects could normally emerge as adults with no visible wing malformation; this indicates that SfCht10 is a lethal gene.…”

Insect group II chitinase OfChtII promotes chitin degradation during larva–pupa molting

“…The group II chitinase (ChtII, also known as Cht10) is a very large chitinase containing 4–5 catalytic domains (CADs) and 4–7 chitin‐binding domains (CBDs). The function of this gene has been studied in many insect species (Royer et al ., 2002; Zhu et al ., 2004; Zhu et al ., 2008a; Nakabachi et al ., 2010; Zhang et al ., 2011b; Pan et al ., 2012; Tetreau et al ., 2015; Liao et al ., 2016; Dong et al ., 2020). It was mainly expressed in the integument during molting and was essential for molting in L. migratoria (Li et al ., 2015), N. lugens (Xi et al ., 2015), Chilo suppressalis (Su et al ., 2016) and O. furnacalis (He et al ., 2013) as assessed by RNAi.…”

Integrated transcriptome sequencing and RNA interference reveals molecular changes in Diaphorina citri after exposure to validamycin

“…An insect's cuticle has multiple functions, such as shaping the inner organs and protecting against dehydration and penetration by xenobiotics and pathogens (Dong et al ., 2020). A main component of the cuticle is polysaccharide chitin, which interacts with chitin‐binding proteins (Moussian et al ., 2006).…”