In Science Advances this week, a Broad Institute team reports data showing that adenine base editors (ABEs) — which are used to convert target A-T base pairs to G-C base pairs in genomic DNA with minimal byproducts — also unexpectedly edit cellular RNA. To address this, they developed new ABE variants that retain their ability to edit DNA efficiently but show greatly reduced RNA editing activity, lower off-target DNA editing activity, and reduced indel byproduct formation in three mammalian cell lines. "By decoupling DNA and RNA editing activities, these ABE variants increase the precision of adenine base editing by minimizing both RNA and DNA off-target editing activity," they write. GenomeWeb has more on this study here.
Also in Science Advances, a group of French investigators publish new details about the structure of the measles virus phosphoprotein, a key component for RNA synthesis of the virus, which may yield insights into the gene expression pathways of other viruses and, potentially, new drug targets. The scientists created a map of the of the phosphoprotein and its interactions with the large protein necessary for RNA polymerization, and found structural motifs associated with viral RNA synthesis. They also discovered that measles gene expression requires cohesiveness and a structural kink in the coiled-coil multimerization domain of the phosphoprotein.