Among alternative splicing events in the human transcriptome, tandem NAGNAG acceptor splice sites represent an appreciable proportion. Both proximal and distal NAG can be used to produce two splicing isoforms differing by three nucleotides. In some cases, the upstream exon can be alternatively spliced as well, which further increases the number of possible transcripts. In this study, we showed that NAG choice in tandem splice site depends considerably not only on the concerned acceptor, but also on the upstream donor splice site sequence. Using an extensive set of experiments with systematically modified two-exonic minigene systems of AFAP1L2 or CSTD gene, we recognized the third and fifth intronic upstream donor splice site position and the tandem acceptor splice site region spanning from -10 to +2, including NAGNAG itself, as the main drivers. In addition, competition between different branch points and their composition were also shown to play a significant role in NAG choice. All these nucleotide effects appeared almost additive, which explained the high variability in proximal versus distal NAG usage.

• Klíčová slova
• AFAP1L2, Alternative splicing, NAG choice, RNA splicing, Splicing isoform,
• MeSH
• alternativní sestřih genetika   MeSH
• exony genetika   MeSH
• HeLa buňky MeSH
• introny genetika   MeSH
• lidé MeSH
• místa sestřihu RNA genetika   MeSH
• nádorové buněčné linie MeSH
• nukleotidy genetika   MeSH
• tandemové repetitivní sekvence genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• místa sestřihu RNA MeSH
• nukleotidy MeSH

UNLABELLED: Mutations affecting splicing underlie the development of many human genetic diseases, but rather rarely through mechanisms of pseudoexon activation. Here, we describe a novel c.1092T>A mutation in the iduronate-2-sulfatase (IDS) gene detected in a patient with significantly decreased IDS activity and a clinical diagnosis of mild mucopolysaccharidosis II form. The mutation created an exonic de novo acceptor splice site and resulted in a complex splicing pattern with multiple pseudoexon activation in the patient's fibroblasts. Using an extensive series of minigene splicing experiments, we showed that the competition itself between the de novo and authentic splice site led to the bypass of the authentic one. This event then resulted in activation of several cryptic acceptor and donor sites in the upstream intron. As this was an unexpected and previously unreported mechanism of aberrant pseudoexon inclusion, we systematically analysed and disproved that the patient's mutation induced any relevant change in surrounding splicing regulatory elements. Interestingly, all pseudoexons included in the mature transcripts overlapped with the IDS alternative terminal exon 7b suggesting that this sequence represents a key element in the IDS pre-mRNA architecture. These findings extend the spectrum of mechanisms enabling pseudoexon activation and underscore the complexity of mutation-induced splicing aberrations. KEY MESSAGE: Novel exonic IDS gene mutation leads to a complex splicing pattern. Mutation activates multiple pseudoexons through a previously unreported mechanism. Multiple cryptic splice site (ss) activation results from a bypass of authentic ss. Authentic ss bypass is due to a competition between de novo and authentic ss.

• Klíčová slova
• Complex splicing aberration, De novo splice site, IDS, Pseudoexon, Splice site competition,
• MeSH
• bodová mutace MeSH
• exony MeSH
• glykoproteiny genetika   MeSH
• introny MeSH
• lidé MeSH
• messenger RNA genetika   MeSH
• místa sestřihu RNA MeSH
• mladiství MeSH
• mukopolysacharidóza II genetika   MeSH
• mutace MeSH
• sestřih RNA MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH
• Názvy látek
• glykoproteiny MeSH
• IDS protein, human MeSH Prohlížeč
• messenger RNA MeSH
• místa sestřihu RNA MeSH

Muscarinic receptors are known to play important biological roles and are drug targets for several human diseases. In a pilot study, novel muscarinic antagonists were synthesized and used as chemical probes to obtain additional information of the muscarinic pharmacophore. The design of these ligands made use of current orthosteric and allosteric models of drug-receptor interactions together with chemical motifs known to achieve muscarinic receptor selectivity. This approach has led to the discovery of several non-competitive muscarinic ligands that strongly bind at a secondary receptor site. These compounds were found to be non-competitive antagonists that completely abolished carbachol activation in functional assays. Several of these compounds antagonized functional response to carbachol with great potency at M1 and M4 than at the rest of receptor subtypes.

• Klíčová slova
• G-protein-coupled receptor, N-methylscopolamine, Parkinson's disease, muscarinic acetylcholine receptor, positive allosteric modulator,
• MeSH
• acetylcholinesterasa metabolismus   MeSH
• alosterická regulace MeSH
• antagonisté muskarinových receptorů chemická syntéza   chemie   metabolismus   MeSH
• CHO buňky MeSH
• Cricetulus MeSH
• křečci praví MeSH
• lidé MeSH
• ligandy MeSH
• N-methylskopolamin chemická syntéza   chemie   metabolismus   MeSH
• pilotní projekty MeSH
• protein - isoformy chemie   genetika   metabolismus   MeSH
• pyridiny chemie   MeSH
• racionální návrh léčiv MeSH
• receptory muskarinové chemie   genetika   metabolismus   MeSH
• vazebná místa MeSH
• zvířata MeSH
• Check Tag
• křečci praví MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• antagonisté muskarinových receptorů MeSH
• ligandy MeSH
• N-methylskopolamin MeSH
• protein - isoformy MeSH
• pyridiny MeSH
• receptory muskarinové MeSH

RNA recognition motif (RRM) proteins represent an abundant class of proteins playing key roles in RNA biology. We present a joint atomistic molecular dynamics (MD) and experimental study of two RRM-containing proteins bound with their single-stranded target RNAs, namely the Fox-1 and SRSF1 complexes. The simulations are used in conjunction with NMR spectroscopy to interpret and expand the available structural data. We accumulate more than 50 μs of simulations and show that the MD method is robust enough to reliably describe the structural dynamics of the RRM-RNA complexes. The simulations predict unanticipated specific participation of Arg142 at the protein-RNA interface of the SRFS1 complex, which is subsequently confirmed by NMR and ITC measurements. Several segments of the protein-RNA interface may involve competition between dynamical local substates rather than firmly formed interactions, which is indirectly consistent with the primary NMR data. We demonstrate that the simulations can be used to interpret the NMR atomistic models and can provide qualified predictions. Finally, we propose a protocol for 'MD-adapted structure ensemble' as a way to integrate the simulation predictions and expand upon the deposited NMR structures. Unbiased μs-scale atomistic MD could become a technique routinely complementing the NMR measurements of protein-RNA complexes.

• MeSH
• konformace proteinů MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie MeSH
• molekulární modely MeSH
• motiv rozpoznávající RNA genetika   MeSH
• multiproteinové komplexy chemie   genetika   MeSH
• RNA chemie   genetika   MeSH
• sekvence aminokyselin genetika   MeSH
• serin-arginin sestřihové faktory chemie   genetika   MeSH
• sestřihové faktory chemie   genetika   MeSH
• simulace molekulární dynamiky MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• multiproteinové komplexy MeSH
• RBFOX1 protein, human MeSH Prohlížeč
• RNA MeSH
• serin-arginin sestřihové faktory MeSH
• sestřihové faktory MeSH
• SRSF1 protein, human MeSH Prohlížeč