Visualizing RNAi at Work
News Jul 06, 2015
The phenomenon of RNAi is expected to find applications in medical treatments. RNAi is mediated by RNA-induced silencing complex (RISC), which contains a small RNA and an Argonaute protein at its core and cleaves the target RNA. However, there were no suitable tools to directly monitor the RNAi reaction and its molecular mechanism by which RISC cleaves the target RNA has remained unclear.
Now, a research group at the University of Tokyo (Professor Takuya Ueda, Professor Yukihide Tomari, Researcher Chunyan Yao and Research Associate Hiroshi M Sasaki,) and at Kyoto University (Researcher Hisashi Tadakuma), has developed a single-molecule imaging assay for observing target RNA cleavage by RISC in a test tube in real time for the first time, showing how RISC accurately cleaves and releases targets. Specifically, their obsercations provide direct evidence for the model that the small RNA in the RISC consists of two parts, one of which quickly binds to the target RNA to be cleaved, while the other proofreads that the correct RNA has been found.
This groundbreaking result reveals RISC’s molecular mechanism of action and the illustration of this process was adopted as the cover design of this issue of the journal. This achievement will also contribute to accelerating the research applications of RNAi such as to the development of RNA-based next-generation drugs, for example as gene therapy to suppress the production of a disease-causing protein.
In a new study in cells, University of Illinois researchers have adapted CRISPR gene-editing technology to cause the cell’s internal machinery to skip over a small portion of a gene when transcribing it into a template for protein building. This gives researchers a way not only to eliminate a mutated gene sequence, but to influence how the gene is expressed and regulated.
Researchers published today a detailed description of the complete genome of bread wheat, the world's most widely-cultivated crop. This work will pave the way for the production of wheat varieties better adapted to climate challenges, with higher yields, enhanced nutritional quality and improved sustainability.