In a recent Cell article, Baluapuri et al.1 show that loss of the Integrator (INT) complex activates the integrated stress response via double-stranded RNA from incomplete pre-mRNAs, revealing a link to INT-related neurodevelopmental diseases and potential therapeutic targets.

• MeSH
• dvouvláknová RNA metabolismus   genetika   MeSH
• fyziologický stres * MeSH
• lidé MeSH
• neurovývojové poruchy * genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dvouvláknová RNA MeSH

Phase separation forms membraneless compartments, including heterochromatin "domains" and repair foci. Pericentromeric heterochromatin mostly comprises repeated sequences prone to aberrant recombination. In Drosophila cells, "safe" homologous recombination (HR) repair of these sequences requires their relocalization to the nuclear periphery before Rad51 recruitment and strand invasion. How this mobilization initiates is unknown, and the contribution of phase separation is unclear. Here, we show that Nup98 nucleoporin is recruited to repair sites before relocalization by Sec13 or Nup88, and downstream of the Smc5/6 complex and heterochromatin protein 1 (HP1). Remarkably, Nup98 condensates are immiscible with HP1 condensates, and they are required and sufficient to mobilize repair sites and exclude Rad51, thus preventing aberrant recombination while promoting HR repair. Disrupting this pathway results in heterochromatin repair defects and widespread chromosome rearrangements, revealing an "off-pore" role for nucleoporins and phase separation in nuclear dynamics and genome integrity in a multicellular eukaryote.

• Klíčová slova
• Nup88, Nup98 condensates, Sec13, double-strand break repair, droplets, heterochromatin repair, homologous recombination, nuclear dynamics, nucleoplasmic nucleoporins, phase separation,
• MeSH
• chromozomální proteiny, nehistonové metabolismus   genetika   MeSH
• Drosophila melanogaster * genetika   metabolismus   MeSH
• dvouřetězcové zlomy DNA MeSH
• heterochromatin * genetika   metabolismus   MeSH
• homolog proteinu s chromoboxem 5 MeSH
• komplex proteinů jaderného póru * metabolismus   genetika   MeSH
• proteiny buněčného cyklu metabolismus   genetika   MeSH
• proteiny Drosophily * metabolismus   genetika   MeSH
• rekombinační oprava DNA * MeSH
• rekombinasa Rad51 * metabolismus   genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chromozomální proteiny, nehistonové MeSH
• heterochromatin * MeSH
• homolog proteinu s chromoboxem 5 MeSH
• komplex proteinů jaderného póru * MeSH
• nuclear pore complex protein 98 MeSH Prohlížeč
• proteiny buněčného cyklu MeSH
• proteiny Drosophily * MeSH
• rekombinasa Rad51 * MeSH

Somatic hypermutation (SHM) and class switch recombination (CSR) diversify immunoglobulin (Ig) genes and are initiated by the activation-induced deaminase (AID), a single-stranded DNA cytidine deaminase thought to engage its substrate during RNA polymerase II (RNAPII) transcription. Through a genetic screen, we identified numerous potential factors involved in SHM, including elongation factor 1 homolog (ELOF1), a component of the RNAPII elongation complex that functions in transcription-coupled nucleotide excision repair (TC-NER) and transcription elongation. Loss of ELOF1 compromises SHM, CSR, and AID action in mammalian B cells and alters RNAPII transcription by reducing RNAPII pausing downstream of transcription start sites and levels of serine 5 but not serine 2 phosphorylated RNAPII throughout transcribed genes. ELOF1 must bind to RNAPII to be a proximity partner for AID and to function in SHM and CSR, and TC-NER is not required for SHM. We propose that ELOF1 helps create the appropriate stalled RNAPII substrate on which AID acts.

• Klíčová slova
• AID, ELOF1, RNA polymerase II, class switch recombination, somatic hypermutation, transcription,
• MeSH
• AICDA (aktivací indukovaná cytidindeamináza) MeSH
• B-lymfocyty * imunologie   metabolismus   MeSH
• cytidindeaminasa metabolismus   genetika   MeSH
• fosfoproteiny * genetika   metabolismus   MeSH
• fosforylace MeSH
• genetická transkripce MeSH
• lidé MeSH
• myši knockoutované MeSH
• myši MeSH
• oprava DNA MeSH
• přesmyk imunoglobulinových tříd * MeSH
• RNA-polymerasa II metabolismus   genetika   MeSH
• somatická hypermutace imunoglobulinových genů * MeSH
• transkripční elongační faktory * genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• AICDA (aktivací indukovaná cytidindeamináza) MeSH
• cytidindeaminasa MeSH
• fosfoproteiny * MeSH
• RNA-polymerasa II MeSH
• transkripční elongační faktory * MeSH

N6-Methyladenosine (m6A) is the predominant internal RNA modification in eukaryotic messenger RNAs (mRNAs) and plays a crucial role in mRNA stability. Here, using human cells, we reveal that m6A sites in the coding sequence (CDS) trigger CDS-m6A decay (CMD), a pathway that is distinct from previously reported m6A-dependent degradation mechanisms. Importantly, CDS m6A sites act considerably faster and more efficiently than those in the 3' untranslated region, which to date have been considered the main effectors. Mechanistically, CMD depends on translation, whereby m6A deposition in the CDS triggers ribosome pausing and transcript destabilization. The subsequent decay involves the translocation of the CMD target transcripts to processing bodies (P-bodies) and recruitment of the m6A reader protein YT521-B homology domain family protein 2 (YTHDF2). Our findings highlight CMD as a previously unknown pathway, which is particularly important for controlling the expression of developmental regulators and retrogenes.

• Klíčová slova
• P-bodies, RNA decay, RNA modification, YTHDF2, coding sequence, m6A, ribosomal A site, ribosome pausing, translation,
• MeSH
• 3' nepřekládaná oblast MeSH
• adenosin * analogy a deriváty   metabolismus   genetika   MeSH
• HEK293 buňky MeSH
• HeLa buňky MeSH
• lidé MeSH
• messenger RNA * genetika   metabolismus   MeSH
• otevřené čtecí rámce * MeSH
• proteiny vázající RNA * genetika   metabolismus   MeSH
• proteosyntéza * MeSH
• ribozomy metabolismus   genetika   MeSH
• stabilita RNA * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 3' nepřekládaná oblast MeSH
• adenosin * MeSH
• messenger RNA * MeSH
• N-methyladenosine MeSH Prohlížeč
• proteiny vázající RNA * MeSH
• YTHDF2 protein, human MeSH Prohlížeč

UV irradiation induces "bulky" DNA photodimers such as (6-4)-photoproducts and cyclobutane pyrimidine dimers that are removed by nucleotide excision repair, a complex process defective in the sunlight-sensitive and cancer-prone disease xeroderma pigmentosum. Some bacteria and lower eukaryotes can also repair photodimers by enzymatically simpler mechanisms, but such pathways have not been reported in normal human cells. Here, we have identified such a mechanism. We show that normal human cells can employ a DNA base excision repair process involving NTH1, APE1, PARP1, XRCC1, and FEN1 to rapidly remove a subset of photodimers at early times following UVC irradiation. Loss of these proteins slows the early rate of repair of photodimers in normal cells, ablates their residual repair in xeroderma pigmentosum cells, and increases UVC sensitivity ∼2-fold. These data reveal that human cells can excise photodimers using a long-patch base excision repair process that functions additively but independently of nucleotide excision repair.

• Klíčová slova
• PARP1, base excision repair, nucleotide excision repair, photoproducts, single-strand break repair,
• MeSH
• DNA genetika   MeSH
• lidé MeSH
• oprava DNA genetika   MeSH
• poškození DNA genetika   MeSH
• protein XRCC1 metabolismus   MeSH
• pyrimidinové dimery genetika   metabolismus   MeSH
• ultrafialové záření MeSH
• xeroderma pigmentosum * genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA MeSH
• protein XRCC1 MeSH
• pyrimidinové dimery MeSH
• XRCC1 protein, human MeSH Prohlížeč

MicroRNA (miRNA) and RNA interference (RNAi) pathways rely on small RNAs produced by Dicer endonucleases. Mammalian Dicer primarily supports the essential gene-regulating miRNA pathway, but how it is specifically adapted to miRNA biogenesis is unknown. We show that the adaptation entails a unique structural role of Dicer's DExD/H helicase domain. Although mice tolerate loss of its putative ATPase function, the complete absence of the domain is lethal because it assures high-fidelity miRNA biogenesis. Structures of murine Dicer•-miRNA precursor complexes revealed that the DExD/H domain has a helicase-unrelated structural function. It locks Dicer in a closed state, which facilitates miRNA precursor selection. Transition to a cleavage-competent open state is stimulated by Dicer-binding protein TARBP2. Absence of the DExD/H domain or its mutations unlocks the closed state, reduces substrate selectivity, and activates RNAi. Thus, the DExD/H domain structurally contributes to mammalian miRNA biogenesis and underlies mechanistical partitioning of miRNA and RNAi pathways.

• Klíčová slova
• DExD, Dicer, PKR, RNAi, TARBP2, cryo-EM, dsRBD, dsRNA, helicase, miRNA, mirtron,
• MeSH
• mikro RNA * genetika   metabolismus   MeSH
• myši MeSH
• ribonukleasa III * metabolismus   MeSH
• RNA interference MeSH
• savci metabolismus   MeSH
• transportní proteiny metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• komentáře MeSH
• práce podpořená grantem MeSH
• Názvy látek
• mikro RNA * MeSH
• ribonukleasa III * MeSH
• transportní proteiny MeSH

In animals and plants, Dicer enzymes collaborate with double-stranded RNA-binding domain (dsRBD) proteins to convert precursor-microRNAs (pre-miRNAs) into miRNA duplexes. We report six cryo-EM structures of Drosophila Dicer-1 that show how Dicer-1 and its partner Loqs‑PB cooperate (1) before binding pre-miRNA, (2) after binding and in a catalytically competent state, (3) after nicking one arm of the pre-miRNA, and (4) following complete dicing and initial product release. Our reconstructions suggest that pre-miRNA binds a rare, open conformation of the Dicer‑1⋅Loqs‑PB heterodimer. The Dicer-1 dsRBD and three Loqs‑PB dsRBDs form a tight belt around the pre-miRNA, distorting the RNA helix to place the scissile phosphodiester bonds in the RNase III active sites. Pre-miRNA cleavage shifts the dsRBDs and partially closes Dicer-1, which may promote product release. Our data suggest a model for how the Dicer‑1⋅Loqs‑PB complex affects a complete cycle of pre-miRNA recognition, stepwise endonuclease cleavage, and product release.

• Klíčová slova
• Dcr-1, Dicer, Dicer-partner proteins, Loqs-PB, Loquacious, RNase III, cryo-EM, dsRBD, isomiR, miRNA, microRNA,
• MeSH
• Drosophila genetika   MeSH
• mikro RNA * genetika   metabolismus   MeSH
• proteiny Drosophily * genetika   metabolismus   MeSH
• proteiny vázající RNA metabolismus   MeSH
• ribonukleasa III genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, N.I.H., Intramural MeSH
• Názvy látek
• mikro RNA * MeSH
• proteiny Drosophily * MeSH
• proteiny vázající RNA MeSH
• ribonukleasa III MeSH

Calcium influx through plasma membrane calcium release-activated calcium (CRAC) channels, which are formed of hexamers of Orai1, is a potent trigger for many important biological processes, most notably in T cell-mediated immunity. Through a bioinformatics-led cell biological screen, we have identified Orai1 as a substrate for the rhomboid intramembrane protease RHBDL2. We show that RHBDL2 prevents stochastic calcium signaling in unstimulated cells through conformational surveillance and cleavage of inappropriately activated Orai1. A conserved disease-linked proline residue is responsible for RHBDL2's recognizing the active conformation of Orai1, which is required to sharpen switch-like signaling triggered by store-operated calcium entry. Loss of RHBDL2 control of CRAC channel activity causes severe dysregulation of downstream CRAC channel effectors, including transcription factor activation, inflammatory cytokine expression, and T cell activation. We propose that this surveillance function may represent an ancient activity of rhomboid proteases in degrading unwanted signaling proteins.

• Klíčová slova
• CRAC channel, Orai1, RHBDL2, T cell, calcium, rhomboid protease, signalling, transmembrane,
• MeSH
• aktivace lymfocytů MeSH
• buněčná membrána metabolismus   MeSH
• Drosophila melanogaster MeSH
• gating iontového kanálu MeSH
• HEK293 buňky MeSH
• konformace proteinů MeSH
• lidé MeSH
• membránové proteiny metabolismus   MeSH
• mutace MeSH
• proteasy chemie   MeSH
• protein ORAI1 chemie   MeSH
• serinové endopeptidasy metabolismus   MeSH
• signální transdukce MeSH
• stochastické procesy MeSH
• vápník metabolismus   MeSH
• vápníková signalizace fyziologie   MeSH
• vápníkové kanály chemie   MeSH
• vazba proteinů MeSH
• výpočetní biologie MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• membránové proteiny MeSH
• ORAI1 protein, human MeSH Prohlížeč
• Orai1 protein, mouse MeSH Prohlížeč
• proteasy MeSH
• protein ORAI1 MeSH
• RHBDL2 protein, human MeSH Prohlížeč
• RHBDL2 protein, mouse MeSH Prohlížeč
• serinové endopeptidasy MeSH
• vápník MeSH
• vápníkové kanály MeSH

DDX3X is a ubiquitously expressed RNA helicase involved in multiple stages of RNA biogenesis. DDX3X is frequently mutated in Burkitt lymphoma, but the functional basis for this is unknown. Here, we show that loss-of-function DDX3X mutations are also enriched in MYC-translocated diffuse large B cell lymphoma and reveal functional cooperation between mutant DDX3X and MYC. DDX3X promotes the translation of mRNA encoding components of the core translational machinery, thereby driving global protein synthesis. Loss-of-function DDX3X mutations moderate MYC-driven global protein synthesis, thereby buffering MYC-induced proteotoxic stress during early lymphomagenesis. Established lymphoma cells restore full protein synthetic capacity by aberrant expression of DDX3Y, a Y chromosome homolog, the expression of which is normally restricted to the testis. These findings show that DDX3X loss of function can buffer MYC-driven proteotoxic stress and highlight the capacity of male B cell lymphomas to then compensate for this loss by ectopic DDX3Y expression.

• Klíčová slova
• Burkitt lymphoma, DDX3X, MYC, RNA helicase, germinal center, proteotoxic stress, translation,
• MeSH
• B-buněčný lymfom enzymologie   genetika   patologie   MeSH
• B-lymfocyty enzymologie   patologie   MeSH
• DEAD-box RNA-helikasy genetika   metabolismus   MeSH
• dítě MeSH
• dospělí MeSH
• homeostáze proteinů MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mutace ztráty funkce MeSH
• myši transgenní MeSH
• nádorové buněčné linie MeSH
• nádorové proteiny biosyntéza   genetika   MeSH
• předškolní dítě MeSH
• proteom MeSH
• proteosyntéza MeSH
• protoonkogenní proteiny c-myc genetika   metabolismus   MeSH
• regulace genové exprese enzymů MeSH
• regulace genové exprese u nádorů MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• stres endoplazmatického retikula MeSH
• vedlejší histokompatibilní antigeny genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DDX3X protein, human MeSH Prohlížeč
• DDX3Y protein, human MeSH Prohlížeč
• DEAD-box RNA-helikasy MeSH
• MYC protein, human MeSH Prohlížeč
• nádorové proteiny MeSH
• proteom MeSH
• protoonkogenní proteiny c-myc MeSH
• vedlejší histokompatibilní antigeny MeSH

RelA-SpoT Homolog (RSH) enzymes control bacterial physiology through synthesis and degradation of the nucleotide alarmone (p)ppGpp. We recently discovered multiple families of small alarmone synthetase (SAS) RSH acting as toxins of toxin-antitoxin (TA) modules, with the FaRel subfamily of toxSAS abrogating bacterial growth by producing an analog of (p)ppGpp, (pp)pApp. Here we probe the mechanism of growth arrest used by four experimentally unexplored subfamilies of toxSAS: FaRel2, PhRel, PhRel2, and CapRel. Surprisingly, all these toxins specifically inhibit protein synthesis. To do so, they transfer a pyrophosphate moiety from ATP to the tRNA 3' CCA. The modification inhibits both tRNA aminoacylation and the sensing of cellular amino acid starvation by the ribosome-associated RSH RelA. Conversely, we show that some small alarmone hydrolase (SAH) RSH enzymes can reverse the pyrophosphorylation of tRNA to counter the growth inhibition by toxSAS. Collectively, we establish RSHs as RNA-modifying enzymes.

• Klíčová slova
• (p)ppApp, (p)ppGpp, RelA-SpoT Homolog, SAH, SAS, ribosome, tRNA modification, toxSAS, toxin-antitoxin, translation,
• MeSH
• bakteriální toxiny genetika   metabolismus   farmakologie   MeSH
• fosforylace účinky léků   MeSH
• grampozitivní nesporulující tyčinky chemie   metabolismus   MeSH
• guanosinpentafosfát chemie   metabolismus   MeSH
• inhibitory syntézy proteinů farmakologie   MeSH
• ligasy chemie   genetika   metabolismus   MeSH
• proteosyntéza účinky léků   fyziologie   MeSH
• pyrofosfatasy MeSH
• ribozomy metabolismus   MeSH
• RNA transferová metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bakteriální toxiny MeSH
• guanosine 3',5'-polyphosphate synthetases MeSH Prohlížeč
• guanosine-3',5'-bis(diphosphate) 3'-pyrophosphatase MeSH Prohlížeč
• guanosinpentafosfát MeSH
• inhibitory syntézy proteinů MeSH
• ligasy MeSH
• pyrofosfatasy MeSH
• RNA transferová MeSH