title: RNA chaperones buffer deleterious mutations in E. coli.
abstract: Both proteins and RNAs can misfold into non-functional conformations. Protein chaperones promote native folding of nascent polypeptides and refolding of misfolded species, thereby buffering mutations that compromise protein structure and function. Here, we show that RNA chaperones can also act as mutation buffers that enhance organismal fitness. Using competition assays, we demonstrate that overexpression of select RNA chaperones, including three DEAD box RNA helicases (DBRHs) (CsdA, SrmB, RhlB) and the cold shock protein CspA, improves fitness of two independently evolved Escherichia coli mutator strains that have accumulated deleterious mutations during short- and long-term laboratory evolution. We identify strain-specific mutations that are deleterious and subject to buffering when introduced individually into the ancestral genotype. For DBRHs, we show that buffering requires helicase activity, implicating RNA structural remodelling in the buffering process. Our results suggest that RNA chaperones might play a fundamental role in RNA evolution and evolvability.
authors: Mediterranean Institute for Life Sciences, Split, Croatia.
authors: Marina
authors: M
authors: Rudan
authors: Laboratoire Adaptation et Pathogénie des Microorganismes, Université Grenoble Alpes, Grenoble, France.
authors: Dominique
authors: D
authors: Schneider
authors: Molecular Systems Group, MRC Clinical Sciences Centre, Imperial College, London, United Kingdom.
authors: Tobias
authors: T
authors: Warnecke
authors: Mediterranean Institute for Life Sciences, Split, Croatia.
authors: Anita
authors: A
authors: Krisko
mesh_terms: D053487:DEAD-box RNA Helicases / Q000737:chemistry; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000378:metabolism; D056084:Genetic Fitness; D018832:Molecular Chaperones / Q000378:metabolism*; D009154:Mutation / Q000235:genetics*; D012329:RNA, Bacterial / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D018832:Molecular Chaperones; D012329:RNA, Bacterial; D053487:DEAD-box RNA Helicases
keywords: E. coli; chaperones; evolution; evolutionary biology; genomics; mutation buffering