CRISPR genome editing

Raghuvir Viswanatha, Roderick Brathwaite, Yanhui Hu, Zhongchi Li, Jonathan Rodiger, Pierre Merckaert, Verena Chung, Stephanie E Mohr, and Norbert Perrimon. 2019. “Pooled CRISPR Screens in Drosophila Cells.” Curr Protoc Mol Biol, 129, 1, Pp. e111.Abstract
High-throughput screens in Drosophila melanogaster cell lines have led to discovery of conserved gene functions related to signal transduction, host-pathogen interactions, ion transport, and more. CRISPR/Cas9 technology has opened the door to new types of large-scale cell-based screens. Whereas array-format screens require liquid handling automation and assay miniaturization, pooled-format screens, in which reagents are introduced at random and in bulk, can be done in a standard lab setting. We provide a detailed protocol for conducting and evaluating genome-wide CRISPR single guide RNA (sgRNA) pooled screens in Drosophila S2R+ cultured cells. Specifically, we provide step-by-step instructions for library design and production, optimization of cytotoxin-based selection assays, genome-scale screening, and data analysis. This type of project takes ∼3 months to complete. Results can be used in follow-up studies performed in vivo in Drosophila, mammalian cells, and/or other systems. © 2019 by John Wiley & Sons, Inc. Basic Protocol: Pooled-format screening with Cas9-expressing Drosophila S2R+ cells in the presence of cytotoxin Support Protocol 1: Optimization of cytotoxin concentration for Drosophila cell screening Support Protocol 2: CRISPR sgRNA library design and production for Drosophila cell screening Support Protocol 3: Barcode deconvolution and analysis of screening data.
Oguz Kanca, Jonathan Zirin, Jorge Garcia-Marques, Shannon Marie Knight, Donghui Yang-Zhou, Gabriel Amador, Hyunglok Chung, Zhongyuan Zuo, Liwen Ma, Yuchun He, Wen-Wen Lin, Ying Fang, Ming Ge, Shinya Yamamoto, Karen L Schulze, Yanhui Hu, Allan C Spradling, Stephanie E Mohr, Norbert Perrimon, and Hugo J Bellen. 2019. “An efficient CRISPR-based strategy to insert small and large fragments of DNA using short homology arms.” Elife, 8.Abstract
We previously reported a CRISPR-mediated knock-in strategy into introns of genes, generating an - transgenic library for multiple uses (Lee et al., 2018b). The method relied on double stranded DNA (dsDNA) homology donors with ~1 kb homology arms. Here, we describe three new simpler ways to edit genes in flies. We create single stranded DNA (ssDNA) donors using PCR and add 100 nt of homology on each side of an integration cassette, followed by enzymatic removal of one strand. Using this method, we generated GFP-tagged proteins that mark organelles in S2 cells. We then describe two dsDNA methods using cheap synthesized donors flanked by 100 nt homology arms and gRNA target sites cloned into a plasmid. Upon injection, donor DNA (1 to 5 kb) is released from the plasmid by Cas9. The cassette integrates efficiently and precisely . The approach is fast, cheap, and scalable.
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
Photo of 384-well assay plates

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.

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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.
flySAM

Missed us at ADRC 2018? View our workshop slides!

April 19, 2018
Thank you to all those who attended our workshop at last week's Annual Drosophila Research Conference in Philadelphia, PA, USA. It was great to talk fly stocks, cell screens, and bioinformatics with the community. We are here to help and look forward to continued feedback on the resources we are building to empower your research. PDFs of our workshop presentations are attached to this news item. The slides will help you learn more about our in vivo resources for CRISPR, new pooled cell-based CRISPR screen technology, and bioinformatics resources at our facility.  Feel free to contact... Read more about Missed us at ADRC 2018? View our workshop slides!
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
Ben Ewen-Campen, Stephanie E Mohr, Yanhui Hu, and Norbert Perrimon. 10/9/2017. “Accessing the Phenotype Gap: Enabling Systematic Investigation of Paralog Functional Complexity with CRISPR.” Dev Cell, 43, 1, Pp. 6-9.Abstract
Single-gene knockout experiments can fail to reveal function in the context of redundancy, which is frequently observed among duplicated genes (paralogs) with overlapping functions. We discuss the complexity associated with studying paralogs and outline how recent advances in CRISPR will help address the "phenotype gap" and impact biomedical research.
Huajin Wang, Michel Becuwe, Benjamin E Housden, Chandramohan Chitraju, Ashley J Porras, Morven M Graham, Xinran N Liu, Abdou Rachid Thiam, David B Savage, Anil K Agarwal, Abhimanyu Garg, Maria-Jesus Olarte, Qingqing Lin, Florian Fröhlich, Hans Kristian Hannibal-Bach, Srigokul Upadhyayula, Norbert Perrimon, Tomas Kirchhausen, Christer S Ejsing, Tobias C Walther, and Robert V Farese. 2016. “Seipin is required for converting nascent to mature lipid droplets.” Elife, 5.Abstract

How proteins control the biogenesis of cellular lipid droplets (LDs) is poorly understood. Using Drosophila and human cells, we show here that seipin, an ER protein implicated in LD biology, mediates a discrete step in LD formation-the conversion of small, nascent LDs to larger, mature LDs. Seipin forms discrete and dynamic foci in the ER that interact with nascent LDs to enable their growth. In the absence of seipin, numerous small, nascent LDs accumulate near the ER and most often fail to grow. Those that do grow prematurely acquire lipid synthesis enzymes and undergo expansion, eventually leading to the giant LDs characteristic of seipin deficiency. Our studies identify a discrete step of LD formation, namely the conversion of nascent LDs to mature LDs, and define a molecular role for seipin in this process, most likely by acting at ER-LD contact sites to enable lipid transfer to nascent LDs.

Benjamin E Housden, Matthias Muhar, Matthew Gemberling, Charles A Gersbach, Didier YR Stainier, Geraldine Seydoux, Stephanie E Mohr, Johannes Zuber, and Norbert Perrimon. 10/31/2016. “Loss-of-function genetic tools for animal models: cross-species and cross-platform differences.” Nat Rev Genet. Publisher's VersionAbstract

Our understanding of the genetic mechanisms that underlie biological processes has relied extensively on loss-of-function (LOF) analyses. LOF methods target DNA, RNA or protein to reduce or to ablate gene function. By analysing the phenotypes that are caused by these perturbations the wild-type function of genes can be elucidated. Although all LOF methods reduce gene activity, the choice of approach (for example, mutagenesis, CRISPR-based gene editing, RNA interference, morpholinos or pharmacological inhibition) can have a major effect on phenotypic outcomes. Interpretation of the LOF phenotype must take into account the biological process that is targeted by each method. The practicality and efficiency of LOF methods also vary considerably between model systems. We describe parameters for choosing the optimal combination of method and system, and for interpreting phenotypes within the constraints of each method.

Benjamin E Housden, Shuailiang Lin, and Norbert Perrimon. 2014. “Cas9-based genome editing in Drosophila.” Methods Enzymol, 546, Pp. 415-39.Abstract

Our ability to modify the Drosophila genome has recently been revolutionized by the development of the CRISPR system. The simplicity and high efficiency of this system allows its widespread use for many different applications, greatly increasing the range of genome modification experiments that can be performed. Here, we first discuss some general design principles for genome engineering experiments in Drosophila and then present detailed protocols for the production of CRISPR reagents and screening strategies to detect successful genome modification events in both tissue culture cells and animals.

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