La Jolla, CA Cells keep a close watch over the transcriptome the totality of all parts of the genome that are expressed in any given cell at any given time. Researchers at the Salk Institute for Biological Studies and the University of Missouri-Kansas City teamed up to peel back another layer of transcriptional regulation and gain new insight into how genomes work.
Converting the genetic blueprint into molecular building blocks requires two basic processes: transcription, which copies the information from DNA into RNA transcripts and takes place in the cells nucleus, and translation, where the RNA serves as a template to manufacture proteins outside the nucleus.
But before transcripts can guide protein synthesis or take on regulatory functions, they have to undergo a strict mRNA surveillance system that degrades defective, obsolete, and surplus transcripts. In their study, published in the Dec. 28 issue of Cell, the scientists zoomed in on a specific subclass of transcripts that are under the control of the exosome, a molecular machine in charge of controlled RNA degradation.
We found evidence for widespread exosome-mediated RNA quality control in plants and a deeply hidden layer of the transcriptome that is tightly regulated by exosome activity, says Joseph R. Ecker, Ph.D., professor in the Plant Biology Laboratory and director of the Salk Institute Genomic Analysis Laboratory.
Since the exosome is in the business of chewing things up, the scientists inactivated the multi-unit complex to bring its otherwise invisible substrates to the fore. Then they combed the transcriptional landscape for hitherto unseen peaks of transcripts that now were untouched by the degrading force of the exosome complex and came up with a genome-wide atlas of Arabidopsis exosome targets.
Our careful design and rigorous validation of the system for conditionally and quickly inactivating the exosome turned out to be really crucial
|Contact: Gina Kirchweger|