Many enhancers control gene expression by assembling regulatory factor clusters, also referred to as condensates. This process is vital for facilitating enhancer communication and establishing cellular identity. However, how DNA sequence and transcription factor (TF) binding instruct the formation of high regulatory factor environments remains poorly understood. Here we developed a new approach leveraging enhancer-centric chromatin accessibility quantitative trait loci (caQTLs) to nominate regulatory factor clusters genome-wide. By analyzing TF-binding signatures within the context of caQTLs and comparing episomal versus endogenous enhancer activities, we discovered a class of regulators, 'context-only' TFs, that amplify the activity of cell type-specific caQTL-binding TFs, that is, 'context-initiator' TFs. Similar to super-enhancers, enhancers enriched for context-only TF-binding sites display high coactivator binding and sensitivity to bromodomain-inhibiting molecules. We further show that binding sites for context-only and context-initiator TFs underlie enhancer coordination, providing a mechanistic rationale for how a loose TF syntax confers regulatory specificity.

• MeSH
• chromatin * genetika   metabolismus   MeSH
• lidé MeSH
• lokus kvantitativního znaku * MeSH
• myši MeSH
• regulace genové exprese MeSH
• transkripční faktory * metabolismus   genetika   MeSH
• vazba proteinů MeSH
• vazebná místa genetika   MeSH
• zesilovače transkripce * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Tandem donor splice sites (5'ss) are unique regions with at least two GU dinucleotides serving as splicing cleavage sites. The Δ3 tandem 5'ss are a specific subclass of 5'ss separated by 3 nucleotides which can affect protein function by inserting/deleting a single amino acid. One 5'ss is typically preferred, yet factors governing particular 5'ss choice are not fully understood. A highly conserved exon 21 of the STAT3 gene was chosen as a model to study Δ3 tandem 5'ss splicing mechanisms. Based on multiple lines of experimental evidence, endogenous U1 snRNA most likely binds only to the upstream 5'ss. However, the downstream 5'ss is used preferentially, and the splice site choice is not dependent on the exact U1 snRNA binding position. Downstream 5'ss usage was sensitive to exact nucleotide composition and dependent on the presence of downstream regulatory region. The downstream 5'ss usage could be best explained by two novel interactions with endogenous U6 snRNA. U6 snRNA enables the downstream 5'ss usage in STAT3 exon 21 by two mechanisms: (i) binding in a novel non-canonical register and (ii) establishing extended Watson-Crick base pairing with the downstream regulatory region. This study suggests that U6:5'ss interaction is more flexible than previously thought.

• MeSH
• exony * MeSH
• HeLa buňky MeSH
• lidé MeSH
• místa sestřihu RNA * MeSH
• RNA malá jaderná * metabolismus   genetika   MeSH
• sekvence nukleotidů MeSH
• sestřih RNA MeSH
• transkripční faktor STAT3 * metabolismus   genetika   MeSH
• vazba proteinů MeSH
• vazebná místa genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

UNLABELLED: Adenovirus (AdV) infection of the respiratory epithelium is common but poorly understood. Human AdV species C types, such as HAdV-C5, utilize the Coxsackie-adenovirus receptor (CAR) for attachment and subsequently integrins for entry. CAR and integrins are however located deep within the tight junctions in the mucosa where they would not be easily accessible. Recently, a model for CAR-independent AdV entry was proposed. In this model, human lactoferrin (hLF), an innate immune protein, aids the viral uptake into epithelial cells by mediating interactions between the major capsid protein, hexon, and yet unknown host cellular receptor(s). However, a detailed understanding of the molecular interactions driving this mechanism is lacking. Here, we present a new cryo-EM structure of HAdV-5C hexon at high resolution alongside a hybrid structure of HAdV-5C hexon complexed with human lactoferrin (hLF). These structures reveal the molecular determinants of the interaction between hLF and HAdV-C5 hexon. hLF engages hexon primarily via its N-terminal lactoferricin (Lfcin) region, interacting with hexon's hypervariable region 1 (HVR-1). Mutational analyses pinpoint critical Lfcin contacts and also identify additional regions within hLF that critically contribute to hexon binding. Our study sheds more light on the intricate mechanism by which HAdV-C5 utilizes soluble hLF/Lfcin for cellular entry. These findings hold promise for advancing gene therapy applications and inform vaccine development. IMPORTANCE: Our study delves into the structural aspects of adenovirus (AdV) infections, specifically HAdV-C5 in the respiratory epithelium. It uncovers the molecular details of a novel pathway where human lactoferrin (hLF) interacts with the major capsid protein, hexon, facilitating viral entry, and bypassing traditional receptors such as CAR and integrins. The study's cryo-EM structures reveal how hLF engages hexon, primarily through its N-terminal lactoferricin (Lfcin) region and hexon's hypervariable region 1 (HVR-1). Mutational analyses identify critical Lfcin contacts and other regions within hLF vital for hexon binding. This structural insight sheds light on HAdV-C5's mechanism of utilizing soluble hLF/Lfcin for cellular entry, holding promise for gene therapy and vaccine development advancements in adenovirus research.

• MeSH
• adenovirové infekce lidí metabolismus   virologie   MeSH
• biologické modely MeSH
• elektronová kryomikroskopie MeSH
• internalizace viru * MeSH
• laktoferrin * chemie   genetika   metabolismus   ultrastruktura   MeSH
• lidé MeSH
• lidské adenoviry * chemie   genetika   metabolismus   ultrastruktura   MeSH
• mutace MeSH
• respirační sliznice cytologie   metabolismus   virologie   MeSH
• rozpustnost MeSH
• vazba proteinů MeSH
• vazebná místa genetika   MeSH
• virové plášťové proteiny * chemie   genetika   metabolismus   ultrastruktura   MeSH
• virové receptory * chemie   genetika   metabolismus   ultrastruktura   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Genome-wide association studies (GWAS) are a powerful tool for detecting variants associated with complex traits and can help risk stratification and prevention strategies against pancreatic ductal adenocarcinoma (PDAC). However, the strict significance threshold commonly used makes it likely that many true risk loci are missed. Functional annotation of GWAS polymorphisms is a proven strategy to identify additional risk loci. We aimed to investigate single-nucleotide polymorphisms (SNP) in regulatory regions [transcription factor binding sites (TFBSs) and enhancers] that could change the expression profile of multiple genes they act upon and thereby modify PDAC risk. We analyzed a total of 12,636 PDAC cases and 43,443 controls from PanScan/PanC4 and the East Asian GWAS (discovery populations), and the PANDoRA consortium (replication population). We identified four associations that reached study-wide statistical significance in the overall meta-analysis: rs2472632(A) (enhancer variant, OR 1.10, 95%CI 1.06,1.13, p = 5.5 × 10-8), rs17358295(G) (enhancer variant, OR 1.16, 95%CI 1.10,1.22, p = 6.1 × 10-7), rs2232079(T) (TFBS variant, OR 0.88, 95%CI 0.83,0.93, p = 6.4 × 10-6) and rs10025845(A) (TFBS variant, OR 1.88, 95%CI 1.50,1.12, p = 1.32 × 10-5). The SNP with the most significant association, rs2472632, is located in an enhancer predicted to target the coiled-coil domain containing 34 oncogene. Our results provide new insights into genetic risk factors for PDAC by a focused analysis of polymorphisms in regulatory regions and demonstrating the usefulness of functional prioritization to identify loci associated with PDAC risk.

• MeSH
• celogenomová asociační studie MeSH
• duktální karcinom slinivky břišní * genetika   patologie   MeSH
• genetická predispozice k nemoci MeSH
• jednonukleotidový polymorfismus genetika   MeSH
• lidé MeSH
• nádory slinivky břišní * genetika   epidemiologie   patologie   MeSH
• regulační oblasti nukleových kyselin MeSH
• transkripční faktory genetika   metabolismus   MeSH
• vazebná místa genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

One of the principal mechanisms of chemotherapy resistance in highly frequent solid tumors, such as colorectal cancer (CRC), is the decreased activity of drug transport into tumor cells due to low expression of important membrane proteins, such as solute carrier (SLC) transporters. Sequence complementarity is a major determinant for target gene recognition by microRNAs (miRNAs). Single-nucleotide polymorphisms (SNPs) in target sequences transcribed into messenger RNA may therefore alter miRNA binding to these regions by either creating a new site or destroying an existing one. miRSNPs may explain the modulation of expression levels in association with increased/decreased susceptibility to common diseases as well as in chemoresistance and the consequent inter-individual variability in drug response. In the present study, we investigated whether miRSNPs in SLC transporter genes may modulate CRC susceptibility and patient's survival. Using an in silico approach for functional predictions, we analyzed 26 miRSNPs in 9 SLC genes in a cohort of 1368 CRC cases and 698 controls from the Czech Republic. After correcting for multiple tests, we found several miRSNPs significantly associated with patient's survival. SNPs in SLCO3A1, SLC22A2 and SLC22A3 genes were defined as prognostic factors in the classification and regression tree analysis. In contrast, we did not observe any significant association between miRSNPs and CRC risk. To the best of our knowledge, this is the first study investigating miRSNPs potentially affecting miRNA binding to SLC transporter genes and their impact on CRC susceptibility or patient's prognosis.

• MeSH
• 3' nepřekládaná oblast genetika   MeSH
• adjuvantní chemoterapie MeSH
• genetická predispozice k nemoci MeSH
• jednonukleotidový polymorfismus MeSH
• kolorektální nádory krev   genetika   mortalita   terapie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• lokální recidiva nádoru epidemiologie   prevence a kontrola   MeSH
• messenger RNA krev   genetika   MeSH
• mikro RNA krev   metabolismus   MeSH
• následné studie MeSH
• přenašeče organických aniontů genetika   MeSH
• prognóza MeSH
• proteiny přenášející organické kationty genetika   MeSH
• regulace genové exprese u nádorů MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• transportér organických kationtů 2 genetika   MeSH
• vazebná místa genetika   MeSH
• výpočetní biologie MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• pozorovací studie MeSH
• práce podpořená grantem MeSH

BACKGROUND: The Hsp70 proteins maintain proteome integrity through the capacity of their nucleotide- and substrate-binding domains (NBD and SBD) to allosterically regulate substrate affinity in a nucleotide-dependent manner. Crystallographic studies showed that Hsp70 allostery relies on formation of contacts between ATP-bound NBD and an interdomain linker, accompanied by SBD subdomains docking onto distinct sites of the NBD leading to substrate release. However, the mechanics of ATP-induced SBD subdomains detachment is largely unknown. METHODS: Here, we investigated the structural and allosteric properties of human HSPA1A using hydrogen/deuterium exchange mass spectrometry, ATPase assays, surface plasmon resonance and fluorescence polarization-based substrate binding assays. RESULTS: Analysis of HSPA1A proteins bearing mutations at the interface of SBD subdomains close to the interdomain linker (amino acids L399, L510, I515, and D529) revealed that this region forms a folding unit stabilizing the structure of both SBD subdomains in the nucleotide-free state. The introduced mutations modulate HSPA1A allostery as they localize to the NBD-SBD interfaces in the ATP-bound protein. CONCLUSIONS: These findings show that residues forming the hydrophobic structural unit stabilizing the SBD structure are relocated during ATP-activated detachment of the SBD subdomains to different NBD-SBD docking interfaces enabling HSPA1A allostery. GENERAL SIGNIFICANCE: Mutation-induced perturbations tuned HSPA1A sensitivity to peptide/protein substrates and to Hsp40 in a way that is common for other Hsp70 proteins. Our results provide an insight into structural rearrangements in the SBD of Hsp70 proteins and highlight HSPA1A-specific allostery features, which is a prerequisite for selective targeting in Hsp-related pathologies.

• MeSH
• adenosintrifosfát chemie   genetika   MeSH
• alosterická regulace genetika   MeSH
• konformace proteinů * MeSH
• lidé MeSH
• mutace genetika   MeSH
• proteinové domény genetika   MeSH
• proteiny tepelného šoku HSP70 chemie   genetika   MeSH
• vazba proteinů genetika   MeSH
• vazebná místa genetika   MeSH
• vodík-deuteriová výměna MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

RNA-binding proteins (RBPs) are critical to posttranscriptional gene regulation. Therefore, characterization of the RNA molecules bound by RBPs in vivo represent a key step in elucidating their function. The recently developed iCLIP technique allows single nucleotide resolution of the RNA binding footprints of RBPs. We present the iCLIP technique modified for its application to Trypanosoma brucei and most likely other kinetoplastid flagellates. By using the immuno- or affinity purification approach, it was successfully applied to the analysis of several RBPs. Furthermore, we also provide a detailed description of the iCLIP/iCLAP protocol that shall be particularly suitable for the studies of trypanosome RBPs.

• MeSH
• imunoprecipitace metody   MeSH
• nukleotidy genetika   metabolismus   MeSH
• parazitologie metody   MeSH
• proteiny vázající RNA analýza   genetika   metabolismus   MeSH
• protozoální proteiny analýza   genetika   metabolismus   MeSH
• RNA protozoální genetika   metabolismus   MeSH
• RNA genetika   metabolismus   MeSH
• Trypanosoma brucei brucei genetika   MeSH
• ultrafialové záření MeSH
• vazba proteinů genetika   účinky záření   MeSH
• vazebná místa genetika   MeSH
• zobrazení jednotlivé molekuly metody   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Staufen1 (STAU1) is a dsRNA binding protein mediating mRNA transport and localization, translational control and STAU1-mediated mRNA decay (SMD). The STAU1 binding site (SBS) within human ADP-ribosylation factor1 (ARF1) 3'UTR binds STAU1 and this downregulates ARF1 cytoplasmic mRNA levels by SMD. However, how STAU1 recognizes specific mRNA targets is still under debate. Our structure of the ARF1 SBS-STAU1 complex uncovers target recognition by STAU1. STAU1 dsRNA binding domain (dsRBD) 4 interacts with two pyrimidines and one purine from the minor groove side via helix α1, the β1-β2 loop anchors the dsRBD at the end of the dsRNA and lysines in helix α2 bind to the phosphodiester backbone from the major groove side. STAU1 dsRBD3 displays the same binding mode with specific recognition of one guanine base. Mutants disrupting minor groove recognition of ARF1 SBS affect in vitro binding and reduce SMD in vivo. Our data thus reveal how STAU1 recognizes minor groove features in dsRNA relevant for target selection.

• MeSH
• ADP-ribosylační faktor 1 chemie   genetika   MeSH
• cytoplazma chemie   genetika   MeSH
• cytoskeletální proteiny chemie   genetika   MeSH
• dvouvláknová RNA chemie   genetika   MeSH
• konformace proteinů MeSH
• lidé MeSH
• proteiny vázající RNA chemie   genetika   MeSH
• stabilita RNA genetika   MeSH
• vazebná místa genetika   MeSH
• vazebný motiv pro dvoušroubovici RNA genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Among all species, caspase-2 (C2) is the most evolutionarily conserved caspase required for effective initiation of apoptosis following death stimuli. C2 is activated through dimerization and autoproteolytic cleavage and inhibited through phosphorylation at Ser139 and Ser164 , within the linker between the caspase recruitment and p19 domains of the zymogen, followed by association with the adaptor protein 14-3-3, which maintains C2 in its immature form procaspase (proC2). However, the mechanism of 14-3-3-dependent inhibition of C2 activation remains unclear. Here, we report the structural characterization of the complex between proC2 and 14-3-3 by hydrogen/deuterium mass spectrometry and protein crystallography to determine the molecular basis for 14-3-3-mediated inhibition of C2 activation. Our data reveal that the 14-3-3 dimer interacts with proC2 not only through ligand-binding grooves but also through other regions outside the central channel, thus explaining the isoform-dependent specificity of 14-3-3 protein binding to proC2 and the substantially higher binding affinity of 14-3-3 protein to proC2 than to the doubly phosphorylated peptide. The formation of the complex between 14-3-3 protein and proC2 does not induce any large conformational change in proC2. Furthermore, 14-3-3 protein interacts with and masks both the nuclear localization sequence and the C-terminal region of the p12 domain of proC2 through transient interactions in which both the p19 and p12 domains of proC2 are not firmly docked onto the surface of 14-3-3. This masked region of p12 domain is involved in C2 dimerization. Therefore, 14-3-3 protein likely inhibits proC2 activation by blocking its dimerization surface. DATABASES: Structural data are available in the Protein Data Bank under the accession numbers 6SAD and 6S9K.

• MeSH
• fosforylace MeSH
• kaspasa 2 chemie   genetika   metabolismus   MeSH
• konformace proteinů * MeSH
• krystalografie rentgenová MeSH
• lidé MeSH
• molekulární modely * MeSH
• multimerizace proteinu * MeSH
• mutace MeSH
• protein - isoformy genetika   metabolismus   MeSH
• proteinové prekurzory chemie   genetika   metabolismus   MeSH
• proteiny 14-3-3 chemie   genetika   metabolismus   MeSH
• rekombinantní proteiny chemie   metabolismus   MeSH
• vazba proteinů MeSH
• vazebná místa genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

FOXO transcription factors are critical regulators of cell homeostasis and steer cell death, differentiation and longevity in mammalian cells. By combined pharmacophore-modeling-based in silico and fluorescence polarization-based screening we identified small molecules that physically interact with the DNA-binding domain (DBD) of FOXO3 and modulate the FOXO3 transcriptional program in human cells. The mode of interaction between compounds and the FOXO3-DBD was assessed via NMR spectroscopy and docking studies. We demonstrate that compounds S9 and its oxalate salt S9OX interfere with FOXO3 target promoter binding, gene transcription and modulate the physiologic program activated by FOXO3 in cancer cells. These small molecules prove the druggability of the FOXO-DBD and provide a structural basis for modulating these important homeostasis regulators in normal and malignant cells.

• MeSH
• DNA chemie   genetika   metabolismus   MeSH
• genetická transkripce účinky léků   MeSH
• genový knockdown MeSH
• HEK293 buňky MeSH
• knihovny malých molekul chemie   metabolismus   farmakologie   MeSH
• konformace nukleové kyseliny MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie MeSH
• molekulární modely MeSH
• nádorové buněčné linie MeSH
• promotorové oblasti (genetika) genetika   MeSH
• protein FOXO3 chemie   genetika   metabolismus   MeSH
• proteinové domény MeSH
• simulace molekulového dockingu MeSH
• stanovení celkové genové exprese metody   MeSH
• vazba proteinů MeSH
• vazebná místa genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH