Search

The spliceosome is shown to catalyse splicing through the RNA and not the protein components of the spliceosome; pre-messenger RNA splicing requires U6 snRNA acting by a mechanism similar to that used by group II self-splicing introns.

The high-resolution crystal structures of apo and self-alkylated ribozymes demonstrate the structural and biochemical basis of carbon–nitrogen bond formation between a specific guanine within the ribozyme and a 2,3-disubstituted epoxide substrate.

Picornaviruses use modular RNA domains in their internal ribosome entry sites (IRESs) for translation through non-canonical, cap-independent mechanisms. Here the authors report the crystal structure of domain V from the IRES of hepatitis A virus (HAV) ssRNA genome, suggesting that the functional homology among different types of picornaviral IRESs is structure-based.

Here the authors report genome-wide profiling of tRNA modifications using Induro-tRNAseq and uncover coordinated changes across cell types and tissues that underlie the basis of protein homeostasis.

Here the authors show that the m¹G9 post-transcriptional methylation differentially regulates the stability of the native and the MELAS variants of human mt-Leu(UAA) tRNA, contributing to mitochondrial pathology.

Non-enzymatic copying of an RNA template is appealing as a transition from pre-life to an RNA world, but it has been difficult to demonstrate in the laboratory. Now, two separate studies focusing on RNA's backbone connectivity offer partial solutions to some of the problems raised with this hypothesis for the origin of life.

The DIR2s RNA aptamer activates the fluorescence of cyanine dyes allowing detection of two well-resolved emission colors. Here authors solve the crystal structures of the apo and OTB-SO3 fluorophore-bound DIR2s and show how the fluorophore ligand is bound.

Spinach is an RNA aptamer analog of GFP that is widely used for fluorescent labeling of cellular RNAs. Crystal structures of Spinach–fluorophore complexes uncover an unusual G-quadruplex RNA fold that is involved in ligand recognition and tuning of Spinach fluorescence properties.

It has long been thought that the catalytic RNAs of self-splicing group II introns and the spliceosome function by similar mechanisms. Now, a combination of genetic, cross-linking, and biochemical analyses of yeast U6 snRNA provide compelling evidence that spliceosomal RNAs form triplex structures similar to those used by group II introns to catalyze splicing.

The results of the Fifth RNA-Puzzles contest highlights advances in RNA three-dimensional structure prediction and uncovers new insights into RNA folding and structure.

An RNA enzyme has been generated that can assemble a mirror-image version of itself. The finding helps to answer a long-standing conundrum about how RNA molecules could have proliferated on prebiotic Earth. See Letter p.440

The first high-resolution views of group II intron maturases illuminate the architectural and functional roles of these multidomain proteins in splicing and DNA invasion. The maturases show striking structural and functional homology to a central protein involved in spliceosomal pre–messenger RNA splicing, thus reinforcing the idea that group II introns and the spliceosome descended from a common ancestor.

In vivo, complex topologies have been identified in proteins and DNA, while their existence in RNA is still unclear. Here, the authors design synthetic topological structures containing single stranded RNA, offering tools for investigating biologically relevant questions about RNA topology.

ROCK (RNA oligomerization-enabled cryo-EM via installing kissing loops) enables improved single-particle cryo-EM of RNAs. ROCK was used to generate high-quality structures of three diverse RNAs, including the Tetrahymena group I intron.

Homooligomerization systems can be used to construct nanoarchitectures and to aid understanding of natural analogues. But the formation of such artificial systems with structural diversity and complexity comparable to that of biological systems is challenging. Now, an artificial branched kissing-loop motif has been designed, which links tiles folded from a single strand of RNA to give diverse homooligomeric nanostructures.

The Varkud satellite ribozyme, which catalyses site-specific RNA cleavage and ligation, is an important model to understand RNA catalysis. Now, a combination of theoretical and experimental work has revealed new details about its catalytic mechanism. Mg²⁺ is shown to play an important role in organizing the active site, and the proton transfers in the transition state have also been identified.

Crystal structures of the full-length VS ribozyme show a domain-swapped dimer that reveals potential mechanisms for cis and trans processing, and suggest convergent evolution in the active site motifs across multiple ribozymes.

Crystallization of RNA molecules can pose a challenge, and the U1A RNA binding protein has been used to facilitate the process. Now a different portable RNA sequence and a synthetic Fab are presented as tools for RNA structural determination. In addition to functioning as a crystallization chaperone, the Fab also serves as the search model to provide phase information.

Drug-resistant bacteria are a growing challenge to world health, and new approaches to antibiotic development are needed. Riboswitches, regulatory elements of mRNA, are shown to be a potential new target for antibiotic drugs.

The CRISPR system uses small RNAs to provide bacteria and archaea with an adaptive defence mechanism against foreign nucleic acids. Recent studies have increased the understanding of mechanisms of CRISPR interference, its roles in microbial physiology and evolution and its potential applications.