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Hans M. Dalton, Raghuvir Viswanatha, Ricky Brathwaite Jr., Jae Sophia Zuno, Stephanie E Mohr, Norbert Perrimon, and Clement Y. Chow. 12/4/2021. “A genome-wide CRISPR screen identifies the glycosylation enzyme DPM1 as a modifier of DPAGT1 deficiency and ER stress.” BioRxiv. Publisher's VersionAbstract
2021.12.03.471178v1.full_.pdf
Partial loss-of-function mutations in glycosylation pathways underlie a set of rare diseases called Congenital Disorders of Glycosylation (CDGs). In particular, DPAGT1 CDG is caused by mutations in the gene encoding the first step in N-glycosylation, DPAGT1, and this disorder currently lacks effective therapies. To identify potential therapeutic targets for DPAGT1-CDG, we performed CRISPR knockout screens in Drosophila cells for genes associated with better survival and glycoprotein levels under DPAGT1 inhibition. We identified hundreds of candidate genes that may be of therapeutic benefit. Intriguingly, inhibition of the mannosyltransferase Dpm1, or its downstream glycosylation pathways, could rescue two in vivo models of DPAGT1 inhibition and ER stress, even though impairment of these pathways alone usually cause CDGs. While both in vivo models ostensibly cause ER stress (through DPAGT1 inhibition or a misfolded protein), we found a novel difference in fructose metabolism that may indicate glycolysis as a modulator of DPAGT1-CDG. Our results provide new therapeutic targets for DPAGT1-CDG, include the unique finding of Dpm1-related pathways rescuing DPAGT1 inhibition, and reveal a novel interaction between fructose metabolism and ER stress.
Yanhui Hu, Sudhir Gopal Tattikota, Yifang Liu, Aram Comjean, Yue Gao, Corey Forman, Grace Kim, Jonathan Rodiger, Irene Papatheodorou, Gilberto Dos Santos, Stephanie E Mohr, and Norbert Perrimon. 2021. “DRscDB: A single-cell RNA-seq resource for data mining and data comparison across species.” Comput Struct Biotechnol J, 19, Pp. 2018-2026.Abstract
DRscDB.pdf
With the advent of single-cell RNA sequencing (scRNA-seq) technologies, there has been a spike in studies involving scRNA-seq of several tissues across diverse species including Drosophila. Although a few databases exist for users to query genes of interest within the scRNA-seq studies, search tools that enable users to find orthologous genes and their cell type-specific expression patterns across species are limited. Here, we built a new search database, DRscDB (https://www.flyrnai.org/tools/single_cell/web/), to address this need. DRscDB serves as a comprehensive repository for published scRNA-seq datasets for Drosophila and relevant datasets from human and other model organisms. DRscDB is based on manual curation of Drosophila scRNA-seq studies of various tissue types and their corresponding analogous tissues in vertebrates including zebrafish, mouse, and human. Of note, our search database provides most of the literature-derived marker genes, thus preserving the original analysis of the published scRNA-seq datasets. Finally, DRscDB serves as a web-based user interface that allows users to mine gene expression data from scRNA-seq studies and perform cell cluster enrichment analyses pertaining to various scRNA-seq studies, both within and across species.
Yanhui Hu, Verena Chung, Aram Comjean, Jonathan Rodiger, Fnu Nipun, Norbert Perrimon, and Stephanie E Mohr. 2020. “BioLitMine: Advanced Mining of Biomedical and Biological Literature About Human Genes and Genes from Major Model Organisms.” G3 (Bethesda).Abstract
4531.full_.pdf
The accumulation of biological and biomedical literature outpaces the ability of most researchers and clinicians to stay abreast of their own immediate fields, let alone a broader range of topics. Although available search tools support identification of relevant literature, finding relevant and key publications is not always straightforward. For example, important publications might be missed in searches with an official gene name due to gene synonyms. Moreover, ambiguity of gene names can result in retrieval of a large number of irrelevant publications. To address these issues and help researchers and physicians quickly identify relevant publications, we developed BioLitMine, an advanced literature mining tool that takes advantage of the medical subject heading (MeSH) index and gene-to-publication annotations already available for PubMed literature. Using BioLitMine, a user can identify what MeSH terms are represented in the set of publications associated with a given gene of the interest, or start with a term and identify relevant publications. Users can also use the tool to find co-cited genes and a build a literature co-citation network. In addition, BioLitMine can help users build a gene list relevant to a MeSH terms, such as a list of genes relevant to "stem cells" or "breast neoplasms." Users can also start with a gene or pathway of interest and identify authors associated with that gene or pathway, a feature that makes it easier to identify experts who might serve as collaborators or reviewers. Altogether, BioLitMine extends the value of PubMed-indexed literature and its existing expert curation by providing a robust and gene-centric approach to retrieval of relevant information.
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.

...

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.
Stephanie E. Mohr and Norbert Perrimon. 9/27/2019. “Drosophila melanogaster: a simple system for understanding complexity.” Dis Model Mech, 12, 10. Publisher's VersionAbstract
2019_DMM_Mohr.pdf

Understanding human gene function is fundamental to understanding and treating diseases. Research using the model organism Drosophila melanogaster benefits from a wealth of molecular genetic resources and information useful for efficient in vivo experimentation. Moreover, Drosophila offers a balance as a relatively simple organism that nonetheless exhibits complex multicellular activities. Recent examples demonstrate the power and continued promise of Drosophila research to further our understanding of conserved gene functions.

Andrey A Parkhitko, Patrick Jouandin, Stephanie E Mohr, and Norbert Perrimon. 2019. “Methionine metabolism and methyltransferases in the regulation of aging and lifespan extension across species.” Aging Cell, Pp. e13034.Abstract
Methionine restriction (MetR) extends lifespan across different species and exerts beneficial effects on metabolic health and inflammatory responses. In contrast, certain cancer cells exhibit methionine auxotrophy that can be exploited for therapeutic treatment, as decreasing dietary methionine selectively suppresses tumor growth. Thus, MetR represents an intervention that can extend lifespan with a complementary effect of delaying tumor growth. Beyond its function in protein synthesis, methionine feeds into complex metabolic pathways including the methionine cycle, the transsulfuration pathway, and polyamine biosynthesis. Manipulation of each of these branches extends lifespan; however, the interplay between MetR and these branches during regulation of lifespan is not well understood. In addition, a potential mechanism linking the activity of methionine metabolism and lifespan is regulation of production of the methyl donor S-adenosylmethionine, which, after transferring its methyl group, is converted to S-adenosylhomocysteine. Methylation regulates a wide range of processes, including those thought to be responsible for lifespan extension by MetR. Although the exact mechanisms of lifespan extension by MetR or methionine metabolism reprogramming are unknown, it may act via reducing the rate of translation, modifying gene expression, inducing a hormetic response, modulating autophagy, or inducing mitochondrial function, antioxidant defense, or other metabolic processes. Here, we review the mechanisms of lifespan extension by MetR and different branches of methionine metabolism in different species and the potential for exploiting the regulation of methyltransferases to delay aging.
Yanhui Hu, Richelle Sopko, Verena Chung, Marianna Foos, Romain A Studer, Sean D Landry, Daniel Liu, Leonard Rabinow, Florian Gnad, Pedro Beltrao, and Norbert Perrimon. 2019. “iProteinDB: An Integrative Database of Post-translational Modifications.” G3 (Bethesda), 9, 1, Pp. 1-11.Abstract
iProteinDB-G3-journal.pdf
Post-translational modification (PTM) serves as a regulatory mechanism for protein function, influencing their stability, interactions, activity and localization, and is critical in many signaling pathways. The best characterized PTM is phosphorylation, whereby a phosphate is added to an acceptor residue, most commonly serine, threonine and tyrosine in metazoans. As proteins are often phosphorylated at multiple sites, identifying those sites that are important for function is a challenging problem. Considering that any given phosphorylation site might be non-functional, prioritizing evolutionarily conserved phosphosites provides a general strategy to identify the putative functional sites. To facilitate the identification of conserved phosphosites, we generated a large-scale phosphoproteomics dataset from embryos collected from six closely-related species. We built iProteinDB (https://www.flyrnai.org/tools/iproteindb/), a resource integrating these data with other high-throughput PTM datasets, including vertebrates, and manually curated information for At iProteinDB, scientists can view the PTM landscape for any protein and identify predicted functional phosphosites based on a comparative analysis of data from closely-related species. Further, iProteinDB enables comparison of PTM data from to that of orthologous proteins from other model organisms, including human, mouse, rat, , , and .
Screenshot of online tools

Navigating our online tools -- orthologs, literature mining, qPCR primers, and so much more!

February 14, 2019

We have been taking a critical look at how we organize our online tools on the Online Tools Overview page. And more generally, we have been thinking about new ways to spread the word about the many resources in our suite of online tools. One way that we at the DRSC like to think about these tools is how they fit into the start-to-finish order of events in a screen or other experimental project. Various tools help define lists of genes to be studied, help identify reagents for the study,...

Read more about Navigating our online tools -- orthologs, literature mining, qPCR primers, and so much more!
Figure 2 from Housden et al 2017 PNAS

Variable Dose Analysis: a new DRSC-supported cell screen approach that leverages existing reagents to perform robust screens

December 1, 2017

We are excited to report the publication of a paper from Benjamin Housden and colleagues describing development and use of the Variable Dose Analysis (VDA) approach. Ben developed a way to use existing TRiP shRNA plasmids originally developed for fly stock production in a new, effective approach to high-throughput cell screening.

The VDA approach is particularly useful for combinatorial approaches that are acutely sensitive to assay robustness. The screen Ben and colleagues report focused on synthetic effects in Drosophila tumor model cells.  The...

Read more about Variable Dose Analysis: a new DRSC-supported cell screen approach that leverages existing reagents to perform robust screens
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.

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