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Using a combination of biochemical, structural and computational analyses, the authors unveil the mechanism of bacterial RNA polymerase pausing and restart mediated by a small-molecule-dependent RNA structural element termed a riboswitch.

The maturation of transfer RNAs requires the splicing of precursor tRNAs by specific endonucleases. New cryo-electron microscopy studies of the human splicing endonuclease bound to tRNAs shed light on how it cleaves and splices its substrates, explaining the function of eukaryote-specific enzyme subunits and rationalizing disease-associated mutations.

The authors perform cryo-EM of pre-tRNA in complex with the human tRNA splicing endonuclease complex TSEN to understand the basis of pre-tRNA recognition and processing by TSEN.

A systematic survey of the budding yeast proteome identifies hundreds of post-transcriptional regulators. Regulatory activity is enriched in RNA-binding proteins but lies outside the RNA-binding domains, often within intrinsically disordered regions.

The authors provide cryo-EM reconstructions of human transfer RNA splicing endonuclease during substrate recognition, rationalizing disease-relevant mutations.

The structure of synapses is critical for brain function. Yu et al. show how the synaptic vesicle protein synaptogyrin binds lipids and helps to ensure that vesicles are uniformly sized, allowing for precise storage of neurotransmitters.

Here, the authors show that anchoring of the PRC2 complex to its own sites requires nuclear condensation of Ccc1, a H3K27me3 reader in the yeast Cryptococcus neoformans, suggesting a functional role for condensates in ensuring heterochromatin fidelity.

The correction of errors during mitochondrial DNA replication by the proofreading function of DNA polymerase-γ is crucial for maintaining the integrity of the mitochondrial genome and the production of cellular energy. Using cryo-electron microscopy, several steps of the DNA polymerase-γ proofreading pathway have been revealed at near-atomic resolution.

Here, the authors show that the lncRNA LoNA links nucleolar structure to epigenetic reprogramming and zygotic genome activation. Loss of LoNA leads to 2C arrest by impairing nucleolar assembly and repression of 2C gene transcription.

Here, using proteomics, molecular biology and sequencing, the authors demonstrate that OGT-dependent O-GlcNAcylation of H4S47 is important for replication-origin activation, presumably through regulating DDK-induced phosphorylation of the MCM complex.

Using cryo-EM, the authors here show that Polγ transitions from replication to error correction by unwinding the DNA, rotating, and backtracking to move the mismatch to the exonuclease site for proofreading.

Here, the authors show that transcripts arising from the X chromosome are less decorated by m⁶A and are more stable than their autosomal counterparts. Consistently, acute depletion of m⁶A preferentially stabilizes autosomal transcripts and thus results in aberrant dosage compensation.

Cilia — or flagella, as they are interchangeably termed — are appendage-like organelles extending from eukaryotic cells. Several recent structural studies on intraflagellar transport (IFT) trains shed light on these fascinating complexes, including their assembly mechanism, stability, cargo recruitment and evolution.

Here the authors show that PIAS3/SENP1-mediated poly-SUMOylation of MAVS regulates its interaction with IRF3, whose SUMO-interacting motif (SIM) guides binding to SUMOylated MAVS. IRF3 phosphorylation, close to its SIM, dismantles SUMO-dependent aggregates and releases activated IRF3.

Here, the authors reveal the architecture of the TRAP complex bound to the translating ribosome and Sec61 translocon, explaining its function in insertion and secretion of proteins, including the insulin hormone, at the endoplasmic reticulum membrane.

The enzymatic activity of PARP1—which adds chains of (poly-ADP)-ribose (PAR) to proteins—initiates DNA repair by leading to more-accessible chromatin and recruitment of PAR-dependent DNA-repair proteins. New work shows that these PARP1-catalysed functions are redirected by the auxiliary factor HPF1 in cells.