Researchers discover RNA repair system in bacteria

October 12, 2009

In new papers appearing this month in Science and the Proceedings of the National Academy of Sciences, University of Illinois biochemistry professor Raven H. Huang and his colleagues describe the first RNA repair system to be discovered in bacteria. This is only the second RNA repair system discovered to date (with two proteins from T4 phage, a virus that attacks bacteria, as the first).

The novelty of the newly discovered bacterial repair system is that, before the damaged RNA is sealed, a methyl group is added to the two-prime hydroxyl group at the cleavage site of the damaged RNA, making it impossible to cleave the site again. Thus, the repaired RNA is "better than new."

This discovery has implications for protecting cells against ribotoxins, a class of toxins that kills cells by cleaving essential RNAs involved in protein translation. Because the enzyme responsible for methylation in the newly-discovered RNA repair system is the Hen1 homolog in bacteria, the finding has also implications for the understanding of and in plants, animals, and other eukaryotes. The eukaryotic Hen1 is one of three enzymes (along with Dicer and Argonaute) essential for the generation of small noncoding RNAs of 19-30 in RNA interference.

While the Science paper describes the mechanism of the entire RNA repair process, the article in PNAS focuses on the chemistry of the methylation reaction, specifically the of the methyltransferase domain of bacterial Hen1. Because the eukaryotic Hen1 carries out the same chemical reaction, the study should further understanding of RNA interference in eukaryotic organisms.

"Hen1 is one of three essential enzymes in generating small noncoding RNAs for RNA interference in eukaryotes," Huang said. "We found out that Hen1 homologs exist in bacteria, but bacteria have no RNA interference. Therefore, we were very curious to find out what bacterial Hen1 is used for."

"Our studies demonstrated that bacterial Hen1 carries out the same chemical reaction as its counterpart in eukaryotes, which was not surprising," he said. "What surprised us was that, instead of involvement in RNA interference, the bacterial Hen1 is part of a RNA repair and modification system. And Hen1 is responsible for producing the repaired RNA that is 'better than new.'"

Source: University of Illinois at Urbana-Champaign (news : web)

Explore further: Prediction of RNA pseudoknots using heuristic modeling with mapping and sequential folding

Related Stories

Class of antibiotics can enhance gene-silencing tool

July 20, 2008

A way to turn off one gene at a time has earned acceptance in biology laboratories over the last decade. Doctors envision the technique, called RNA interference, as a tool to treat a variety of diseases if it can be adapted ...

Researchers Studying Little-Known Genetic Sequences

November 13, 2008

( -- University of Arizona researchers are among a group of scientists who have discovered a source of previously scarce small RNA molecules. Their finding, which was recently published in the Proceedings of the ...

Recommended for you

'Hog-nosed rat' discovered in Indonesia

October 6, 2015

Museum of Natural Science Curator of Mammals Jake Esselstyn at Louisiana State University and his international collaborators have discovered a new genus and species on a remote, mountainous island in Indonesia. This new ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.