RNAi: A Success Story
It all started in the 1980s when plant scientists first observed the effects of transcriptional inhibition by antisense RNA expressed in transgenic plants (Ecker, J.R. and Davis, R.W., 1986). Several unexpected findings in plant genomics demonstrated the induction of post-transcriptional inhibition after transfecting specific RNA into the system (Napoli, C. et al, 1990, Romano, N. and Macino, G., 1992). About a decade later, scientists gained sufficient understanding of the RNAi phenomenon to apply this natural process as a research tool to both cell culture and living organisms. The successful introduction of a synthetic double stranded RNA into the nematode worm C. elegans to deliberately induce suppression of specific genes of interest gained Andrew Fire and Craig C. Mello the shared Nobel Prize in Physiology or Medicine in 2006.
RNAi is the method of choice for loss-of-function studies to unravel the function of a gene in vivo by selectively turning down their expression or activity.
Screening in days rather than weeks
High throughput cell imaging technology and advanced analysis methods have successfully improved RNAi methodologies. It is enabling fast genome-wide screening and helping us to better understand the complexity of many biological processes, such as apoptosis and cell cycle analysis, that are, despite great scientific efforts, still not fully understood.
The application of RNAi in genome-wide cell-based assay screens allows for the simultaneous analysis of thousands of genes, to identify those playing a critical role in cellular processes or events such as:
- Protein kinase activity
- Cell cycle
- Organism development
- Spheroid formation
Efficient cell imagers like the acumen® (TTP Labtech) are capable of combining fast whole well imaging – up to 300,000 samples screened per day – with cell number measurements, allowing you to normalise responses to total cell number. This approach has been particularly successful for the observation of cell-division phenotypes, such as cell cycle arrest or altered ploidy. In this study, for example, novel functions to genes in mitosis and cytokinesis has allowed genes to be grouped into functional classes (Kittler et al. (2007), Nature Cell Biology).
If you are interested in how our acumen has been successfully applied in other fields such as Immunity (Karlas et al. (2010) Nature) or Oncogenesis (Gerlinger et al. (2012), The Journal of Pathology), please follow the links to the original publications or find out more about acumen on the acumen product pages.