Genome complexity: how riboswitches work to control genes (Introduction)

by David Turell , Monday, March 28, 2022, 20:57 (753 days ago) @ David Turell

Great new study:

https://phys.org/news/2022-03-unprecedented-videos-rna.html

"Similar to a light switch, RNA switches (called riboswitches) determine which genes turn "on" and "off." Although this may seem like a simple process, the inner workings of these switches have confounded biologists for decades.

"Now researchers led by Northwestern University and the University at Albany discovered one part of RNA smoothly invades and displaces another part of the same RNA, enabling the structure to rapidly and dramatically change shape. Called "strand displacement," this mechanism appears to switch genetic expression from "on" to "off."

"Using a simulation they launched last year, the researchers made this discovery by watching a slow-motion simulation of a riboswitch up close and in action. Affectionately called R2D2 (short for "reconstructing RNA dynamics from data"), the new simulation models RNA in three dimensions as it binds to a compound, communicates along its length and folds to turn a gene "on" or "off."

***

"Although RNA folding takes place in the human body more than 10 quadrillion times per second—every time a gene is expressed in a cell—researchers know very little about the process. To help visualize and understand the mysterious yet crucial process, Lucks and Chen unveiled R2D2 last year, in a paper published in the journal Molecular Cell. (my bold)

***

"Riboswitches have two basic parts. One part binds to a compound. Then, depending on how the compound is bound, the second part causes the RNA to fold into a shape that allows it to control gene expression. While these two parts are intertwined and overlapping in many riboswitches, the Bacillus subtilis is different.

"'What's strange is that they are separated by a long distance, but the bound molecule can cause large functional changes," Lucks said. "If the chemical binds at one end, then how is that communicated downstream to the other end of the RNA? It's been a mystery."

***

"Lucks, Chen and their teams found the riboswitch likely communicates downstream through the strand displacement mechanism. In response to the chemical binding, the strand exchange process triggers structural switching between "on" and "off" states."

Comment: Another level of complexity in genome design in control of gene activation or suppression. Another of God's designed switch mechanisms for precise controls. Note the required speed! Not surprising, a mistake can happen. dhw doesn't understand the import in theodicy discussions.