|Nature Structural aamp; Molecular Biology - Issue - nature.com science feeds|
Unlike in animals in which gastrulation marks the onset of zygotic transcription and a transition from random to site-specific localization of replication origins, transcription and origin specification in Caenorhabditis elegans are in place before gastrulation. Nonetheless, origin-site redistribution takes place after gastrulation, and is coordinated with changes in the sites of active transcription.
This Review highlights recent breakthroughs in X-chromosome inactivation and discusses how the multitasking RNA Xist can structurally and functionally transform an active chromosome into uniquely organized facultative heterochromatin.
Crystal structures of the linker region of TRPML1 reveal that the luminal domain forms a tetrameric pore. Along with electrophysiology studies, this work provides insight into the mechanism of channel regulation by Ca2+ and H+.
The cryo-EM structure of pre-60S purified via Nmd3 provides molecular insights into the roles of assembly factors Nmd3, Lsg1, Tif6 and Reh1 in the last steps of ribosomal large-subunit maturation.
Using a family of spectrin domain variants and a combination of structural, biochemical and biophysical approaches, it is shown that cotranslational folding cannot be predicted on the basis of the folding behavior of isolated proteins.
Single-cell RNA sequencing of preimplantation mouse embryos demonstrates that lack of paternal Xist leads to genome-wide transcriptional misregulation in the early blastocyst and a failure to activate the extraembryonic pathway.
The molecular chaperone HSP90 is found to affect the expression of mouse endogenous retrovirus elements and neighboring genes through the KAP1–SETDB1 epigenetic-repression machinery.
Guanine-rich sequences with a tendency to form G4 structures are a hallmark of hominoid-specific L1 retrotransposons, and their stabilization increases L1 mobility, thus potentially affecting genome evolution.
Structural, biochemical and in vivo analyses reveal that Rad50 zinc-hook and coiled-coil domains form a novel dimerization interface essential for Mre11-complex function in DNA damage response and repair.
A genetic screen in C. elegans identifies a suppressor of siRNA and a new subset of 22G-RNAs that act through the nuclear RNAi pathway to downregulate pre-rRNA under stress conditions.
The specificity of USP18's deconjugating activity toward ISG15, a ubiquitin-like protein induced by interferon, is revealed by structural and biochemistry studies of the mouse proteins.
STAT2, previously known as a positive effector of interferon signaling, is now shown to participate in negative feedback and suppression of this signaling pathway, by recruiting USP18 to the type I IFN receptor subunit IFNAR2.
Nascent-strand mapping of active DNA replication origins before and after gastrulation in C. elegans reveals that replication initiation is coordinated with transcriptional programs during embryonic development.
A high-resolution cryo-EM structure of the heptameric Cdt1–Mcm2–7 complex of the replicative helicase from budding yeast suggests a ‘spring-action’ DNA-unwinding mechanism.
smFRET analysis and colocalization spectroscopy reveal the mechanism of DNA entry into the Mcm2–7 helicase ring during replication origin licensing.
A 3.9-Å-resolution cryo-EM structure of the S. cerevisiae OCCM replicative helicase loading complex bound to DNA shows how ORC and Cdc6 recognize DNA origins, and reveals details of how the Mcm2–7 hexamer ring is loaded onto the DNA helix.
A comprehensive analysis of the human SUMO proteome, in HeLa and U2OS cell lines and under different conditions, identifies new SUMOylated sites and reveals cross-talk between SUMO and other post-translational modifications, such as phosphorylation.
|Nature Structural aamp; Molecular Biology - AOP - nature.com science feeds|
A cytosolic isoform of Ezh1 that lacks the catalytic domain controls nuclear PRC2 activity in response to atrophic oxidative stress in skeletal muscle cells by trapping Eed in the cytoplasm.
Human OGA forms an unusual arm-in-arm homodimer with a substrate-binding cleft that affords extensive interactions with the peptide substrate in a recognition mode distinct from that of its bacterial homologs.
A 20S proteasome complex localizes to neuronal plasma membrane, where it produces and releases extracellular peptides that induce neuronal calcium signaling.
Capture Hi-C analysis reveals that DNA double-strand breaks within transcriptionally active regions of the human genome form clusters that exhibit delayed repair in the G1 phase of the cell cycle.
Cryo-EM analyses provide a near-atomic view of the C. elegans securin–separase complex, with insights into the mechanism by which securin inhibits separase's protease activity.
TOP2 collaborates with the BAF complex genome-wide to form and resolve facultative heterochromatin at transcriptional regulatory elements recognized by pluripotency factors.
Crystal structure analysis combined with sequencing approaches uncover a broad T cell receptor repertoire and reveal the structural basis of influenza M1 epitope recognition.
HIV Tat binding to the exterior of Aβ fibrils induces lateral aggregation and formation of fibers with increased adhesion, rigidity and mechanical resistance, thus potentially accounting for their higher neurotoxicity.
Cryo-EM analyses of the initial contact of the HIV-1 Env trimer with the CD4 receptor reveal that CD4 interacts with two gp120 protomers; these quaternary contacts are important for viral infectivity.
The interaction of Hsp90 with misfolded monomeric transthyretin is characterized via biophysical approaches, and the data indicate that Hsp90 may have a distinct recognition mode for aggregation-prone proteins.
Structural determination and analysis of HLA-I that presents an HIV-derived peptide to an NK cell receptor reveal that N-terminal extended epitope conformations contribute to immune recognition and mechanisms of HIV immune escape.