Researchers Show How DNA Repair Proteins
Researchers from the Salk Institute for Biological Studies recently discovered critical details regarding how DNA repair proteins. The study, according to researchers, reveals fundamental mechanisms that distinguish DNA breaks at cellular and viral genomes to trigger different responses that protect the host. The findings also help explain why certain conditions like aging, cancer immunotherapy and inflammation make viral infection more likely. Many factors, such as radiation, can cause a break in our DNA. The team detailed how a cluster of proteins — collectively called the MRN complex — detects both DNA and viral breaks and amplifies its response through histones, packaging proteins that wrap genetic material into small bundles. MRN starts a domino effect, activating histones on surrounding chromosomes, which summons a cascade of additional proteins, resulting in a cell-wide, all-hands-on-deck alarm to help mend the DNA. Typically, a common DNA virus enters the cell’s nucleus and turns on genes to replicate its own DNA. The cell detects the unauthorized replication and the MRN complex grabs and selectively neutralizes viral DNA without triggering a global response that would arrest or kill the cell. The difference in the intensity of its response, explained the Salk researchers, is similar to sending a text message for a local flood warning (in the case of the DNA virus) versus a citywide tsunami siren (DNA break). The MRN response to the virus stays localized and only selectively prevents viral, but not cellular, replication. If every incoming virus spurred a similarly strong response, our cells would be frequently paused, hampering our growth. To read more about this study, click here.
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