A Genetic Screen Using theDrosophila melanogasterTRiP RNAi Collection To Identify Metabolic Enzymes Required for Eye Development

Abstract

The metabolic enzymes that compose glycolysis, the citric acid cycle, and other pathways within central carbon metabolism have emerged as key regulators of animal development. These enzymes not only generate the energy and biosynthetic precursors required to support cell proliferation and differentiation, but also moonlight as regulators of transcription, translation, and signal transduction. Many of the genes associated with animal metabolism, however, have never been analyzed in a developmental context, thus highlighting how little is known about the intersection of metabolism and development. Here we address this deficiency by using the Drosophila TRiP RNAi collection to disrupt the expression of over 1,100 metabolism-associated genes within cells of the eye imaginal disc. Our screen not only confirmed previous observations that oxidative phosphorylation serves a critical role in the developing eye, but also implicated a host of other metabolic enzymes in the growth and differentiation of this organ. Notably, our analysis revealed a requirement for glutamine and glutamate metabolic processes in eye development, thereby revealing a role of these amino acids in promoting Drosophila tissue growth. Overall, our analysis highlights how the Drosophila eye can serve as a powerful tool for dissecting the relationship between development and metabolism.

Neural stem cell temporal patterning and brain tumour growth rely on oxidative phosphorylation

“…We used RNAi to knock down subunits of complex I (NDUFS1) or complex V (ATPsynα) in NSCs and tumour cells with a NSC-specific driver, Worniu-GAL4 (Albertson et al, 2004). The complex I RNAi line has been validated previously (Garcia et al, 2017; Hermle et al, 2017; Owusu-Ansah et al, 2013; Pletcher et al, 2019); expression of the complex V RNAi in NSCs strongly reduced the levels of ATPsynα (Figure 1—figure supplement 2a–c). We also assessed mitochondrial morphology by stimulated emission-depletion (STED) super-resolution microscopy of mitochondria-targeted GFP (Rizzuto et al, 1995).…”

Trehalose metabolism confers developmental robustness and stability in Drosophila by regulating glucose homeostasis

“…Consistently, we found that the level of trehalose hydrolysis impacts organ size, although the observed effects are relatively mild. The tissue-specific knockdown of glycolytic genes in eyes and wing imaginal discs have been reported to have little, if any, impacts on normal morphogenesis and organ size 39,40 , suggesting that other metabolic pathways compensate for reduced glycolysis during normal development. However, reductions in glycolytic activity can attenuate JNKinduced cell death and TGFβ/Hipk-driven tissue overgrowth in imaginal discs 39,41,42 .…”

An RNAi Screen for Genes Required for Growth ofDrosophilaWing Tissue

“…Other reports have shown that that Nit2 has an effect on cell proliferation and may be a tumor suppressor (Lin et al 2007; Zheng et al 2015). A recent report showed that knockdown of CG8132 also strongly impaired growth and development of the Drosophila eye (Pletcher et al 2019). Further characterization of the eye and wing phenotypes in flies will further define CG8132 / Nit2 cellular functions.…”

“…In a number of different human populations, alleles of GCDH cause the metabolic disorder glutaric acidemia type I, an early-onset neurodegenerative disorder (Table 3) (Goodman et al 1995; Hedlund et al 2006; Schmiesing et al 2017; Schmiesing et al 2018). In Drosophila , expression of CG9547 is upregulated in response to starvation and oxidative stress, and its knockdown altered eye growth (Fujikawa et al 2009; Gruenewald et al 2009; Pletcher et al 2019).…”

“…Six of the genes fall into the broad class of metabolism and / or organismal physiology ( Cisd2 , CG12171 , CG4459 , CG8132 , CG9547 , CG4459 ). Notably, a recent candidate shRNA screen of genes with known or predicted metabolic function showed that CG8132 , CG9547 , and CG4459 also influence growth of the Drosophila eye disc (Pletcher et al 2019). The cellular activity of these metabolic genes in vivo remains incompletely defined, and an important question is whether their activity is similar among all cells or modulated in concert with the development and function of different cell types.…”