Paper shredder part of surveillance system
by MikeGeneCells 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 cell's 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"¦"¦"¦"¦"¦ "It is likely that these RNAs that are usually "˜deeply hidden' become important for genome function or stability under some circumstances", adds co-first author Julia Chekanova, an assistant at the University of Missouri-Kansas City. "We need to do more work to figure out what these circumstances are."
December 28th, 2007 at 10:51 am
This was a fascinating bit of research and should be humbling to those who think our theoretical conceptualizations of how cells functions are all neatly explained and tucked away for ready reference. Possibilities are rich for design inferences if one is willing to ask the right questions.
Comment by Bradford — December 28, 2007 @ 10:51 am
December 28th, 2007 at 1:33 pm
This is very cool and analogous to how data communication protocols are engineered to detect and compensate for errors. I wonder if there are other predictions that could be made regarding cellular mechanisms starting with the assumption that the cell is largely an engineered system.
For example, it seems to me that genes are comparable to the data that computer programs operate on. However, are there epigenetic mechanisms similar to a computer program or state machine that specify higher level processes such as the sequence in which genes are transcribed, and what to do with the resulting proteins.
Comment by David — December 28, 2007 @ 1:33 pm
December 28th, 2007 at 1:47 pm
David:
Those upper level processes can become experimental focal points about which causal flow is assessed. It is currently presummed that lower level events generate higher level processes and without a great deal of observational support. Supporting evidence is primarily comparative sequences. Actual biological functions demonstrate a necessity for higher level controls without revealing specific pathways to them that would result from lower level events.
Comment by Bradford — December 28, 2007 @ 1:47 pm
December 29th, 2007 at 12:16 am
Why Mike, this reminds me of a little e-mail exchange we had the other day…
Comment by Wonders For Oyarsa — December 29, 2007 @ 12:16 am