Drosophila (fly)

Julia Wang, Rami Al-Ouran, Yanhui Hu, Seon-Young Kim, Ying-Wooi Wan, Michael F Wangler, Shinya Yamamoto, Hsiao-Tuan Chao, Aram Comjean, Stephanie E Mohr, Undiagnosed Diseases Network, Norbert Perrimon, Zhandong Liu, and Hugo J Bellen. 6/1/2017. “MARRVEL: Integration of Human and Model Organism Genetic Resources to Facilitate Functional Annotation of the Human Genome.” Am J Hum Genet, 100, 6, Pp. 843-853.Abstract
One major challenge encountered with interpreting human genetic variants is the limited understanding of the functional impact of genetic alterations on biological processes. Furthermore, there remains an unmet demand for an efficient survey of the wealth of information on human homologs in model organisms across numerous databases. To efficiently assess the large volume of publically available information, it is important to provide a concise summary of the most relevant information in a rapid user-friendly format. To this end, we created MARRVEL (model organism aggregated resources for rare variant exploration). MARRVEL is a publicly available website that integrates information from six human genetic databases and seven model organism databases. For any given variant or gene, MARRVEL displays information from OMIM, ExAC, ClinVar, Geno2MP, DGV, and DECIPHER. Importantly, it curates model organism-specific databases to concurrently display a concise summary regarding the human gene homologs in budding and fission yeast, worm, fly, fish, mouse, and rat on a single webpage. Experiment-based information on tissue expression, protein subcellular localization, biological process, and molecular function for the human gene and homologs in the seven model organisms are arranged into a concise output. Hence, rather than visiting multiple separate databases for variant and gene analysis, users can obtain important information by searching once through MARRVEL. Altogether, MARRVEL dramatically improves efficiency and accessibility to data collection and facilitates analysis of human genes and variants by cross-disciplinary integration of 18 million records available in public databases to facilitate clinical diagnosis and basic research.
Yanhui Hu, Aram Comjean, Stephanie E Mohr, The FlyBase Consortium, and Norbert Perrimon. 8/7/2017. “Gene2Function: An Integrated Online Resource for Gene Function Discovery.” G3 (Bethesda).Abstract
One of the most powerful ways to develop hypotheses regarding biological functions of conserved genes in a given species, such as in humans, is to first look at what is known about function in another species. Model organism databases (MODs) and other resources are rich with functional information but difficult to mine. Gene2Function (G2F) addresses a broad need by integrating information about conserved genes in a single online resource.
Screenshot of a 2015 Science paper from Payre and colleagues

Francois Payre's plenary talk at ADRC 2017 features results from DRSC cell-based screen

March 30, 2017

Those of us lucky enough to be at the Annual Drosophila Research Conference this morning saw a great talk by Francois Payre about regulation of Shavenbaby by small ORFs. A genome-wide cell-based screen done at the DRSC by Emilie Benrabah identified the mechanism of regulation. As this exemplifies, cell screens can help identify key pathways and factors that can then be followed up with in vivo studies.

J Zanet, E Benrabah, T Li, A Pélissier-Monier, H Chanut-Delalande, B Ronsin, HJ Bellen, F Payre, and S Plaza. 2015. “Pri sORF peptides induce selective proteasome-mediated protein processing.” Science, 349, 6254, Pp. 1356-8.Abstract

A wide variety of RNAs encode small open-reading-frame (smORF/sORF) peptides, but their functions are largely unknown. Here, we show that Drosophila polished-rice (pri) sORF peptides trigger proteasome-mediated protein processing, converting the Shavenbaby (Svb) transcription repressor into a shorter activator. A genome-wide RNA interference screen identifies an E2-E3 ubiquitin-conjugating complex, UbcD6-Ubr3, which targets Svb to the proteasome in a pri-dependent manner. Upon interaction with Ubr3, Pri peptides promote the binding of Ubr3 to Svb. Ubr3 can then ubiquitinate the Svb N terminus, which is degraded by the proteasome. The C-terminal domains protect Svb from complete degradation and ensure appropriate processing. Our data show that Pri peptides control selectivity of Ubr3 binding, which suggests that the family of sORF peptides may contain an extended repertoire of protein regulators.

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.

New stocks added to the TRiP in vivo RNAi library

January 6, 2017

The TRiP has updated and curated our list of in vivo RNAi reagents for gene knockdown in fruitflies. To date, we have produced over 13,000 stocks for the benefit of the scientific community.

Visit the in vivo RNAi fly stocks and vectors page to download an excel file with the full list of fly stocks now available for order from the Bloomington Drosophila Stock Center (BDSC) and the...

Read more about New stocks added to the TRiP in vivo RNAi library

CRISPR sgRNA design tool now based on Drosophila genome assembly 6

December 21, 2016

We have updated our CRISPR sgRNA design tool. The results and JBrowse display are now based on Drosophila melanogaster FlyBase genome assembly release 6. We have also added seed scores in addition to efficiency prediction scores and other values available on detailed views of sgRNA designs. Quick tips: start a search with a gene symbol or other identifier, use the...

Read more about CRISPR sgRNA design tool now based on Drosophila genome assembly 6
Chen X and Xu L. 2016. “Genome-Wide RNAi Screening to Dissect the TGF-β Signal Transduction Pathway.” Methods in Molecular Biology. Publisher's VersionAbstract

The transforming growth factor-β (TGF-β) family of cytokines figures prominently in regulation of embryonic development and adult tissue homeostasis from Drosophila to mammals. Genetic defects affecting TGF-β signaling underlie developmental disorders and diseases such as cancer in human. Therefore, delineating the molecular mechanism by which TGF-β regulates cell biology is critical for understanding normal biology and disease mechanisms. Forward genetic screens in model organisms and biochemical approaches in mammalian tissue culture were instrumental in initial characterization of the TGF-β signal transduction pathway. With complete sequence information of the genomes and the advent of RNA interference (RNAi) technology, genome-wide RNAi screening emerged as a powerful functional genomics approach to systematically delineate molecular components of signal transduction pathways. Here, we describe a protocol for image-based whole-genome RNAi screening aimed at identifying molecules required for TGF-β signaling into the nucleus. Using this protocol we examined >90 % of annotated Drosophila open reading frames (ORF) individually and successfully uncovered several novel factors serving critical roles in the TGF-β pathway. Thus cell-based high-throughput functional genomics can uncover new mechanistic insights on signaling pathways beyond what the classical genetics had revealed.