The RNAi Global Initiative Meets in Barcelona to Discuss Best Practices in High Throughput RNAi-based Screens

Queta Smith, Ph.D.

The members of the RNAi Global Initiative met on 26-28 September 2007 at the Hesperia Presidente Conference Center in Barcelona, Spain, to share experiences with, and data resulting from, genome-wide screening efforts. The RNAi Global Initiative, an academic alliance that includes the R&D team at Thermo Fisher Scientific, has pursued the development and promotion of best practices and strategies for high throughput screening and high content analysis. The entire group utilizes the siGENOME® SMARTpool® siRNA library (Thermo Scientific Dharmacon Products) which covers the whole-human genome and serves as one of their primary tools for genome-wide silencing studies. The ultimate goal of their work is to identify the function of those genes critical for normal and disease processes to facilitate drug development and therapeutic strategies.

At this fifth meeting of the group’s biannual gatherings, representatives from each member institute had the opportunity to report on research developments in their labs in addition to the results of collaborative focus group activities. The Informatics Workgroup reported progress on their efforts to lead the larger community towards establishing standardized reporting methods for RNAi-based screens. This effort, referred to as Minimal Information About RNAi Experiments (MIARE), has focused on facilitating meaningful comparisons of screening results from different laboratories. The workgroup leaders, represented by the University of Edinburgh (Division of Pathway Medicine), Harvard and the German Cancer Center, have created a website where the broader scientific community may comment on these proposed standards. Parallel discussions by group members with interests in high content screening, cancer, and infectious disease took place, allowing the dissemination of new findings and strategies in these fields.

In addition to workgroup activities and reports from individual research groups, members also reviewed common themes that arise in high throughput screening platforms. Of particular interest to many who are actively screening - what are the best strategies to validate candidate gene targets derived from primary RNAi-based screens? The consensus was that this bears closer examination and while this issue will likely evolve over time, researchers currently have a range of choices. These include confirmation of phenotypes with independent reagents or assays – whether independent ON-TARGETplus™ SMARTpool reagents that are enhanced for specificity, novel reagents like SMARTvector™ lentiviral shRNA reagents, non-RNAi reagents like small molecule compounds and/or strategies including rescreens in dominant-negative backgrounds or the application of high content approaches that permit multi-parametric analysis of distinct phenotypes.

The RNAi Global Initiative continues to serve as an example of a true working group where researchers have the opportunity to focus on daily challenges from managing reagent collections, optimizing and implementing assays, and collecting, validating and interpreting screening results.