Damage to our DNA can lead to serious, sometimes fatal consequences, which is why understanding the different response mechanisms used by our body is of crucial importance. 

Now, a team of researchers from Ludwig Maximilians University, Munich, led by Professor Klaus Förstemann, have found a novel mechanism by which fruit flies deal with damage to their DNA. Their work appears online on the July 30 issue of the journal Nucleic Acids Research.

Every cell in our body host double-stranded genomic DNA. RNA is molecule derived from DNA, which play many different roles, from replication DNA to translating its genetic code into proteins. But RNA does a lot more, and one type of RNA, known as short-interfering RNA, or siRNA is now shown to serve a repair function when a specific type of DNA damage occurs. Most errors affecting DNA occurs on one of the two strands, and usually the unaffected strand is used as template to repair the one. But sometimes damage occurs on both strands, the so called double-strand breaks or DSBs, which represent a major problem for DNA function. "These lesions are so dangerous because the likelihood of imprecise repair is higher, and parts of the hereditary information can wind up in the wrong context," says Prof. Förstemann. "We have now shown in Drosophila that this type of damage induces the production of siRNAs." In this work siRNA is shown, for the first time, to be involved in the repair response of the cell, at least in fruit flies.

Understanding the full details of this mechanism will still require much research, and researchers think this mechanism is likely also present in other groups such as plants, fungi, and even human cells. "How siRNAs function in the recognition and repair of DNA damage has not been conclusively established," Förstemann explains."But clearly, this is a mechanism that has been highly conserved during evolution."

Original article: A small RNA response at DNA ends in Drosophila