Cell-based RNAi

Jiunn Song, Arda Mizrak, Chia-Wei Lee, Marcelo Cicconet, Zon Weng Lai, Chieh-Han Lu, Stephanie E. Mohr, Jr Robert V. Farese, and Tobias C. Walther. 9/15/2021. “Identification of two pathways mediating protein targeting from ER to lipid droplets”. Publisher's VersionAbstract
Pathways localizing proteins to their sites of action within a cell are essential for eukaryotic cell organization and function. Although mechanisms of protein targeting to many organelles have been defined, little is known about how proteins, such as key metabolic enzymes, target from the ER to cellular lipid droplets (LDs). Here, we identify two distinct pathways for ER-to-LD (ERTOLD) protein targeting: early ERTOLD, occurring during LD formation, and late ERTOLD, targeting mature LDs after their formation. By using systematic, unbiased approaches, we identified specific membrane-fusion machinery, including regulators, a tether, and SNARE proteins, that are required for late ERTOLD targeting. Components of this fusion machinery localize to LD-ER interfaces and appear to be organized at ER exit sites (ERES) to generate ER-LD membrane bridges. We also identified multiple cargoes for early and late ERTOLD. Collectively, our data provide a new model for how proteins target LDs from the ER.
Graphical image of tissue culture, fly pushing, and computer, and the team of people who work with them

DRSC/TRiP and DRSC-BTRR Office Hours

September 13, 2021

New this fall: Online office hours!

Do you have questions about modifying Drosophila cell lines with CRISPR or performing large-scale cell screens? Questions about in vivo RNAi with TRiP fly stocks or CRISPR knockout or activation with our sgRNA fly stocks? Questions about our new protocols and resources for CRISPR mosquito cell lines? Pop into our Zoom office hours to say hello and get our expert input! Registration is required (see below).

DRSC/TRiP & DRSC-BTRR Office Hours Schedule:

Mon. Sept. 27, 2021, 12...

Read more about DRSC/TRiP and DRSC-BTRR Office Hours
Xiangzhao Yue, Yongkang Liang, Zhishuang Wei, Jun Lv, Yongjin Cai, Xiaobin Fan, Wenqing Zhang, and Jie Chen. 2021. “Genome-wide in vitro and in vivo RNAi screens reveal Fer3 to be an important regulator of kkv transcription in Drosophila.” Insect Sci.Abstract
Krotzkopf verkehrt (kkv) is a key enzyme that catalyzes the synthesis of chitin, an important component of the Drosophila epidermis, trachea, and other tissues. Here, we report the use of comprehensive RNA interference (RNAi) analyses to search for kkv transcriptional regulators. A cell-based RNAi screen identified 537 candidate kkv regulators on a genome-wide scale. Subsequent use of transgenic Drosophila lines expressing RNAi constructs enabled in vivo validation, and we identified six genes as potential kkv transcriptional regulators. Weakening of the kkvDsRed signal, an in vivo reporter indicating kkv promoter activity, was observed when the expression of Akirin, NFAT, 48 related 3 (Fer3), or Autophagy-related 101(Atg101) was knocked down in Drosophila at the 3rd-instar larval stage; whereas we observed disoriented taenidial folds on larval tracheae when Lines (lin) or Autophagy-related 3(Atg3) was knocked down in the tracheae. Fer3, in particular, has been shown to be an important factor in the activation of kkv transcription via specific binding with the kkv promoter. The genes involved in the chitin synthesis pathway were widely affected by the downregulation of Fer3. Furthermore, Atg101, Atg3, Akirin, Lin, NFAT, Pnr and Abd-A showed the potential complex mechanism of kkv transcription are regulated by an interaction network with bithorax complex components. Our study revealed the hitherto unappreciated diversity of modulators impinging on kkv transcription and opens new avenues in the study of kkv regulation and chitin biosynthesis. This article is protected by copyright. All rights reserved.
Graphical image of tissue culture, fly pushing, and computer, and the team of people who work with them

DRSC-Biomedical Technology Research Resource

October 21, 2019

We are pleased to announce that we have been funded by NIH NIGMS to form the Drosophila Research & Screening Center-Biomedical Technology Research Resource (DRSC-BTRR). The P41-funded DRSC-BTRR (N. Perrimon, PI; S. Mohr, Co-I) builds upon and extends past goals of the Drosophila RNAi Screening Center.

As the DRSC-BTRR, we are working together with collaborators whose 'driving biomedical projects' inform development of new technologies at the DRSC. At the same time, we continue to support Drosophila cell-based RNAi and CRIPSR knockout screens and related...

Read more about DRSC-Biomedical Technology Research Resource
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Drosophila cell screen with DRSC reagent library contributes to identification of new therapeutic target for renal cancer

October 7, 2019

We here at the DRSC/TRiP are thrilled to see this study from Hilary Nicholson et al. published in Science Signaling.

The study provides a great example of how screens in Drosophila cultured cells can be used as part of a cross-species platform aimed at discovery of new targets for disease treatment. The work represents a collaboration between the laboratory of 2019 Nobel Prize winner W. Kaelin and DRSC PI N. Perrimon.

...

Read more about Drosophila cell screen with DRSC reagent library contributes to identification of new therapeutic target for renal cancer
Hilary E Nicholson, Zeshan Tariq, Benjamin E Housden, Rebecca B Jennings, Laura A Stransky, Norbert Perrimon, Sabina Signoretti, and William G Kaelin. 2019. “HIF-independent synthetic lethality between CDK4/6 inhibition and VHL loss across species.” Sci Signal, 12, 601.Abstract
Inactivation of the tumor suppressor gene is the signature initiating event in clear cell renal cell carcinoma (ccRCC), the most common form of kidney cancer, and causes the accumulation of hypoxia-inducible factor 2α (HIF-2α). HIF-2α inhibitors are effective in some ccRCC cases, but both de novo and acquired resistance have been observed in the laboratory and in the clinic. Here, we identified synthetic lethality between decreased activity of cyclin-dependent kinases 4 and 6 (CDK4/6) and inactivation in two species (human and ) and across diverse human ccRCC cell lines in culture and xenografts. Although HIF-2α transcriptionally induced the CDK4/6 partner cyclin D1, HIF-2α was not required for the increased CDK4/6 requirement of ccRCC cells. Accordingly, the antiproliferative effects of CDK4/6 inhibition were synergistic with HIF-2α inhibition in HIF-2α-dependent ccRCC cells and not antagonistic with HIF-2α inhibition in HIF-2α-independent cells. These findings support testing CDK4/6 inhibitors as treatments for ccRCC, alone and in combination with HIF-2α inhibitors.
Cartoon of fly host cells with virus or endosymbiotic bacteria

Cell-based RNAi screening helps reveal host-microbe interactions--two new screen reports

November 19, 2018

Laboratories at the Skirball Institute at New York University and the Boyce Thompson Institute at Cornell University reported results of two different cell-based Drosophila RNAi screens in papers published this week. The screens have in common that they looked at interactions between the host insect cells and a microbe -- the endosymbiont Wolbachia in one study and baculovirus in the other. For more, check out the newly published studies. For both these screens, the DRSC provided libraries for screens that were then performed at the host institution.

 

... Read more about Cell-based RNAi screening helps reveal host-microbe interactions--two new screen reports
Hirotaka Kanoh, Li-Li Tong, Takayuki Kuraishi, Yamato Suda, Yoshiki Momiuchi, Fumi Shishido, and Shoichiro Kurata. 2015. “Genome-wide RNAi screening implicates the E3 ubiquitin ligase Sherpa in mediating innate immune signaling by Toll in Drosophila adults.” Sci Signal, 8, 400, Pp. ra107.Abstract
The Drosophila Toll pathway plays important roles in innate immune responses against Gram-positive bacteria and fungi. To identify previously uncharacterized components of this pathway, we performed comparative, ex vivo, genome-wide RNA interference screening. In four screens, we overexpressed the Toll adaptor protein dMyd88, the downstream kinase Pelle, or the nuclear factor κB (NF-κB) homolog Dif, or we knocked down Cactus, the Drosophila homolog of mammalian inhibitor of NF-κB. On the basis of these screens, we identified the E3 ubiquitin ligase Sherpa as being necessary for the activation of Toll signaling. A loss-of-function sherpa mutant fly exhibited compromised production of antimicrobial peptides and enhanced susceptibility to infection by Gram-positive bacteria. In cultured cells, Sherpa mediated ubiquitylation of dMyd88 and Sherpa itself, and Sherpa and Drosophila SUMO (small ubiquitin-like modifier) were required for the proper membrane localization of an adaptor complex containing dMyd88. These findings highlight a role for Sherpa in Drosophila host defense and suggest the SUMOylation-mediated regulation of dMyd88 functions in Toll innate immune signaling.
Hirotaka Kanoh, Takayuki Kuraishi, Li-Li Tong, Ryo Watanabe, Shinji Nagata, and Shoichiro Kurata. 2015. “Ex vivo genome-wide RNAi screening of the Drosophila Toll signaling pathway elicited by a larva-derived tissue extract.” Biochem Biophys Res Commun, 467, 2, Pp. 400-6.Abstract
Damage-associated molecular patterns (DAMPs), so-called "danger signals," play important roles in host defense and pathophysiology in mammals and insects. In Drosophila, the Toll pathway confers damage responses during bacterial infection and improper cell-fate control. However, the intrinsic ligands and signaling mechanisms that potentiate innate immune responses remain unknown. Here, we demonstrate that a Drosophila larva-derived tissue extract strongly elicits Toll pathway activation via the Toll receptor. Using this extract, we performed ex vivo genome-wide RNAi screening in Drosophila cultured cells, and identified several signaling factors that are required for host defense and antimicrobial-peptide expression in Drosophila adults. These results suggest that our larva-derived tissue extract contains active ingredients that mediate Toll pathway activation, and the screening data will shed light on the mechanisms of damage-related Toll pathway signaling in Drosophila.
2018 Apr 13

DRSC & TRiP Workshop at ADRC

1:45pm to 3:45pm

Location: 

Philadelphia, PA, USA
The DRSC & TRiP will be hosting a workshop at the Annual Drosophila Research Conference in Philadelphia, PA. The workshop is scheduled for Friday, April 13th from 1:45 to 3:45 PM. Come hear from DRSC & TRiP leaders Norbert Perrimon, Jonathan Zirin (organizer), Claire Yanhui Hu, and Stephanie Mohr. At the workshop, you will learn about new opportunities for community nomination and experiments using CRISPR knockout and activation, as well as learn what's new and popular among our online software and database tools. There will be something for everyone -- we will provide information... Read more about DRSC & TRiP Workshop at ADRC
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Congrats to Sung, Shears, and colleagues: "Cytokine signaling through Drosophila Mthl10 ties lifespan to environmental stress"

December 13, 2017

Eui Jae Sung, Stephen Shears, and colleagues have published a research report that includes a screen of dsRNAs from the DRSC reagent collection using S2 cells. We shipped dsRNA reagents to the lab for a screen at their home institution, in addition to providing consultation and data management support. The resulting study by Sung et al. was published on Dec. 11, 2017: Sung EJ, Ryuda M, Matsumoto H, Uryu O, Ochiai M, Cook ME, Yi NY, Wang H, Putney JW, Bird GS, Shears SB, Hayakawa Y. Cytokine signaling through Drosophila Mthl10 ties lifespan to environmental stress...

Read more about Congrats to Sung, Shears, and colleagues: "Cytokine signaling through Drosophila Mthl10 ties lifespan to environmental stress"
Stephanie E Mohr, Kirstin Rudd, Yanhui Hu, Wei R Song, Quentin Gilly, Michael Buckner, Benjamin E Housden, Colleen Kelley, Jonathan Zirin, Rong Tao, Gabriel Amador, Katarzyna Sierzputowska, Aram Comjean, and Norbert Perrimon. 12/9/2017. “Zinc Detoxification: A Functional Genomics and Transcriptomics Analysis in Drosophila melanogaster Cultured Cells.” G3 (Bethesda).Abstract
Cells require some metals, such as zinc and manganese, but excess levels of these metals can be toxic. As a result, cells have evolved complex mechanisms for maintaining metal homeostasis and surviving metal intoxication. Here, we present the results of a large-scale functional genomic screen in Drosophila cultured cells for modifiers of zinc chloride toxicity, together with transcriptomics data for wildtype or genetically zinc-sensitized cells challenged with mild zinc chloride supplementation. Altogether, we identified 47 genes for which knockdown conferred sensitivity or resistance to toxic zinc or manganese chloride treatment, and more than 1800 putative zinc-responsive genes. Analysis of the 'omics data points to the relevance of ion transporters, glutathione-related factors, and conserved disease-associated genes in zinc detoxification. Specific genes identified in the zinc screen include orthologs of human disease-associated genes CTNS, PTPRN (also known as IA-2), and ATP13A2 (also known as PARK9). We show that knockdown of red dog mine (rdog; CG11897), a candidate zinc detoxification gene encoding an ABCC-type transporter family protein related to yeast cadmium factor (YCF1), confers sensitivity to zinc intoxication in cultured cells and that rdog is transcriptionally up-regulated in response to zinc stress. As there are many links between the biology of zinc and other metals and human health, the 'omics datasets presented here provide a resource that will allow researchers to explore metal biology in the context of diverse health-relevant processes.

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