Tuesday, April 30, 2019

in vivo RNAi screen for metabolic enzymes required for eye development

Rose C. Pletcher, Sara L. Hardman, Sydney F. Intagliata, Rachel L. Lawson, Aumunique Page and Jason M. Tennessen

A Genetic Screen Using the Drosophila melanogaster TRiP RNAi Collection To Identify Metabolic Enzymes Required for Eye Development

G3: GENES, GENOMES, GENETICS Early online April 29, 2019; https://doi.org/10.1534/g3.119.400193

http://www.g3journal.org/content/early/2019/04/29/g3.119.400193

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."

RNAi screen for genes in escort cells related to germ cell maintenance and differentiation

Gao Y, Mao Y, Xu RG, Zhu R, Zhang M, Sun J, Shen D, Peng P, Xie T, Ni JQ. Defining gene networks controlling the maintenance and function of the differentiation niche by an in vivo systematic RNAi screen. J Genet Genomics. 2019 Jan 20;46(1):19-30. PMID: 30745214.

Abstract: "In the Drosophila ovary, escort cells (ECs) extrinsically control germline stem cell (GSC) maintenance and progeny differentiation. However, the underlying mechanisms remain poorly understood. In this study, we identified 173 EC genes for their roles in controlling GSC maintenance and progeny differentiation by using an in vivo systematic RNAi approach. Of the identified genes, 10 and 163 are required in ECs to promote GSC maintenance and progeny differentiation, respectively. The genes required for progeny differentiation fall into different functional categories, including transcription, mRNA splicing, protein degradation, signal transduction and cytoskeleton regulation. In addition, the GSC progeny differentiation defects caused by defective ECs are often associated with BMP signaling elevation, indicating that preventing BMP signaling is a general functional feature of the differentiation niche. Lastly, exon junction complex (EJC) components, which are essential for mRNA splicing, are required in ECs to promote GSC progeny differentiation by maintaining ECs and preventing BMP signaling. Therefore, this study has identified the major regulators of the differentiation niche, which provides important insights into how stem cell progeny differentiation is extrinsically controlled."

Optogenetic tools for Drosophila S2 cells

Osswald M, Santos AF, Morais-de-Sá E. Light-Induced Protein Clustering for Optogenetic Interference and Protein Interaction Analysis in Drosophila S2 Cells. Biomolecules. 2019 Feb 12;9(2). pii: E61. doi: 10.3390/biom9020061. PubMed PMID: 30759894; PubMed Central PMCID: PMC6406598.

Abstract: "Drosophila Schneider 2 (S2) cells are a simple and powerful system commonly used in cell biology because they are well suited for high resolution microscopy and RNAi-mediated depletion. However, understanding dynamic processes, such as cell division, also requires methodology to interfere with protein function with high spatiotemporal control. In this research study, we report the adaptation of an optogenetic tool to Drosophila S2 cells. Light-activated reversible inhibition by assembled trap (LARIAT) relies on the rapid light-dependent heterodimerization between cryptochrome 2 (CRY2) and cryptochrome-interacting bHLH 1 (CIB1) to form large protein clusters. An anti-green fluorescent protein (GFP) nanobody fused with CRY2 allows this method to quickly trap any GFP-tagged protein in these light-induced protein clusters. We evaluated clustering kinetics in response to light for different LARIAT modules, and showed the ability of GFP-LARIAT to inactivate the mitotic protein Mps1 and to disrupt the membrane localization of the polarity regulator Lethal Giant Larvae (Lgl). Moreover, we validated light-induced co-clustering assays to assess protein-protein interactions in S2 cells. In conclusion, GFP-based LARIAT is a versatile tool to answer different biological questions, since it enables probing of dynamic processes and protein-protein interactions with high spatiotemporal resolution in Drosophila S2 cells."

Monday, February 11, 2019

Screen explores possible roles of ion channels in Drosophila wing development

George LF, Pradhan SJ, Mitchell D, Josey M, Casey J, Belus MT, Dahal GR, Bates EA. Ion Channel Contributions to Wing Development in Drosophila melanogaster. G3 (Bethesda). 2019 Feb 7. pii: g3.400028.2019. doi: 10.1534/g3.119.400028. PMID: 30733380.

Abstract: "During morphogenesis, cells communicate with each other to shape tissues and organs. Several lines of recent evidence indicate that ion channels play a key role in cellular signaling and tissue morphogenesis. However, little is known about the scope of specific ion-channel types that impinge upon developmental pathways. The Drosophila melanogaster wing is an excellent model in which to address this problem as wing vein patterning is acutely sensitive to changes in developmental pathways. We conducted a screen of 180 ion channels expressed in the wing using loss-of-function mutant and RNAi lines. Here we identify 44 candidates that significantly impacted development of the Drosophila melanogaster wing. Calcium, sodium, potassium, chloride, and ligand-gated cation channels were all identified in our screen, suggesting that a wide variety of ion channel types are important for development. Ion channels belonging to the pickpocket family, the ionotropic receptor family, and the bestrophin family were highly represented among the candidates of our screen. Seven new ion channels with human orthologs that have been implicated in human channelopathies were also identified. Many of the human orthologs of the channels identified in our screen are targets of common general anesthetics, anti-seizure and anti-hypertension drugs, as well as alcohol and nicotine. Our results confirm the importance of ion channels in morphogenesis and identify a number of ion channels that will provide the basis for future studies to understand the role of ion channels in development."

Large-scale RNAi screen in red flour beetle (Tribolium) to identify genes involved in muscle development

Schultheis D, Weißkopf M, Schaub C, Ansari S, Dao VA, Grossmann D, Majumdar U, Hakeemi MS, Troelenberg N, Richter T, Schmitt-Engel C, Schwirz J, Ströhlein N, Teuscher M, Bucher G, Frasch M. A Large Scale Systemic RNAi Screen in the Red Flour Beetle Tribolium castaneum Identifies Novel Genes Involved in Insect Muscle Development. G3 (Bethesda). 2019 Feb 7. pii: g3.200995.2018. PMID: 30733381.


Schultheis D, Schwirz J, Frasch M. RNAi Screen in Tribolium Reveals Involvement of F-BAR Proteins in Myoblast Fusion and Visceral Muscle Morphogenesis in Insects. G3 (Bethesda). 2019 Feb 7. pii: g3.200996.2018. doi: 10.1534/g3.118.200996. PMID: 30733382.

Monday, November 26, 2018

Report of detection of miRNAs in cell-free media from cultured Drosophila cells

Van den Brande S, Gijbels M, Wynant N, Santos D, Mingels L, Gansemans Y, Van Nieuwerburgh F, Vanden Broeck J. The presence of extracellular microRNAs in the media of cultured Drosophila cells. Sci Rep. 2018 Nov 23;8(1):17312. PMID: 30470777.

Abstract: "While regulatory RNA pathways, such as RNAi, have commonly been described at an intracellular level, studies investigating extracellular RNA species in insects are lacking. In the present study, we demonstrate the presence of extracellular microRNAs (miRNAs) in the cell-free conditioned media of two Drosophila cell lines. More specifically, by means of quantitative real-time PCR (qRT-PCR), we analysed the presence of twelve miRNAs in extracellular vesicles (EVs) and in extracellular Argonaute-1 containing immunoprecipitates, obtained from the cell-free conditioned media of S2 and Cl.8 cell cultures. Next-generation RNA-sequencing data confirmed our qRT-PCR results and provided evidence for selective miRNA secretion in EVs. To our knowledge, this is the first time that miRNAs have been identified in the extracellular medium of cultured cells derived from insects, the most speciose group of animals."

Monday, November 19, 2018

RNAi screen used to identify host cell factors required for baculovirus entry

Hodgson JJ, Buchon N, Blissard GW. Identification of insect genes involved in baculovirus AcMNPV entry into insect cells. Virology. 2018 Nov 13;527:1-11. doi: 10.1016/j.virol.2018.10.022. PMID: 30445201.

Abstract: "The baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a model enveloped DNA virus that infects and replicates in lepidopteran insect cells, and can efficiently enter a wide variety of non-host cells. Budded virions of AcMNPV enter cells by endocytosis and traffic to the nucleus where the virus initiates gene expression and genome replication. While trafficking of nucleocapsids by actin propulsion has been studied in detail, other important components of trafficking during entry remain poorly understood. We used a recombinant AcMNPV virus expressing an EGFP reporter in combination with an RNAi screen in Drosophila DL1 cells, to identify host proteins involved in AcMNPV entry. The RNAi screen targeted 86 genes involved in vesicular trafficking, including genes coding for VPS and ESCRT proteins, Rab GTPases, Exocyst proteins, and Clathrin adaptor proteins. We identified 24 genes required for efficient virus entry and reporter expression, and 4 genes that appear to restrict virus entry. "