Significant proportion of human diseases is genetically determined and successful treatment is dependent on precise diagnosis of causal mutations. However, their identification is not always so unambiguous, although relevant sequence data is available. Modern genomic methods are able to uncover a considerable number of sequence variants with unknown impact on disease. Sequence variants frequently influence the gene expression through alteration of pre-mRNA splicing, but this effect can be hidden, if the splicing regulatory function of mutated regions was not proven in advance. The identification of splicing regulatory elements (SREs) is therefore a crucial step in evaluation of each mutation as potentially pathogenic. The aim of the project is to localize functional SREs and to try to define some rules for their occurrence by performing a systematic experimental analysis of ten regions in genes involved in disease development. Acquired „hot spot“ map of splicing affecting regions should act as an additional tool for diagnostics of aberrant splicing in newly identified gene variants.

Značná část lidských chorob má genetickou příčinu a pro úspěšnou léčbu je často nezbytné přesně určit, která mutace chorobu způsobuje. Identifikace kauzálních mutací však není vždy jednoznačná, a to i tehdy, máme-li k dispozici relevantní sekvence DNA. Moderní celogenomové metody odhalí řadu sekvenčních variant, u kterých není příčinná souvislost s chorobou zřejmá. Mnohé varianty ovlivňují genovou expresi změnou sestřihu pre-mRNA, ale tento efekt nemusí být odhalen, pokud nebylo již dříve prokázáno, že daná oblast obsahuje regulační elementy sestřihu (SRE). Jejich identifikace je proto klíčovým faktorem pro vyhodnocení vlivu takových mutací na vznik choroby. Projekt si klade za cíl lokalizovat funkční SRE a pokusit se nalézt obecná pravidla jejich výskytu v cílových sekvencích. Proto bude provedena systematická experimentální analýza vybraných oblastí genů, které jsou zodpovědné za vznik závažných lidských chorob. Získaná mapa míst náchylných k mutacím vyvolávajícím změny sestřihu bude využita jako pomocný nástroj pro diagnostiku aberantního sestřihu u nově identifikovaných mutací.

• MeSH
• genetická predispozice k nemoci MeSH
• genetické nemoci vrozené genetika   MeSH
• lidé MeSH
• mutace genetika   MeSH
• sestřih RNA genetika   MeSH
• Check Tag
• lidé MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• genetika, lékařská genetika
• NLK Publikační typ
• závěrečné zprávy o řešení grantu AZV MZ ČR

Acceptor splice site recognition (3' splice site: 3'ss) is a fundamental step in precursor messenger RNA (pre-mRNA) splicing. Generally, the U2 small nuclear ribonucleoprotein (snRNP) auxiliary factor (U2AF) heterodimer recognizes the 3'ss, of which U2AF35 has a dual function: (i) It binds to the intron-exon border of some 3'ss and (ii) mediates enhancer-binding splicing activators' interactions with the spliceosome. Alternative mechanisms for 3'ss recognition have been suggested, yet they are still not thoroughly understood. Here, we analyzed 3'ss recognition where the intron-exon border is bound by a ubiquitous splicing regulator SRSF1. Using the minigene analysis of two model exons and their mutants, BRCA2 exon 12 and VARS2 exon 17, we showed that the exon inclusion correlated much better with the predicted SRSF1 affinity than 3'ss quality, which were assessed using the Catalog of Inferred Sequence Binding Preferences of RNA binding proteins (CISBP-RNA) database and maximum entropy algorithm (MaxEnt) predictor and the U2AF35 consensus matrix, respectively. RNA affinity purification proved SRSF1 binding to the model 3'ss. On the other hand, knockdown experiments revealed that U2AF35 also plays a role in these exons' inclusion. Most probably, both factors stochastically bind the 3'ss, supporting exon recognition, more apparently in VARS2 exon 17. Identifying splicing activators as 3'ss recognition factors is crucial for both a basic understanding of splicing regulation and human genetic diagnostics when assessing variants' effects on splicing.

• MeSH
• alternativní sestřih genetika   MeSH
• exony genetika   MeSH
• HeLa buňky MeSH
• introny genetika   MeSH
• lidé MeSH
• místa sestřihu RNA genetika   fyziologie   MeSH
• proteiny vázající RNA metabolismus   MeSH
• regulační oblasti nukleových kyselin genetika   MeSH
• sekvence nukleotidů genetika   MeSH
• serin-arginin sestřihové faktory metabolismus   MeSH
• sestřih RNA fyziologie   MeSH
• sestřihové faktory metabolismus   fyziologie   MeSH
• sestřihový faktor U2AF metabolismus   MeSH
• spliceozomy metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

PURPOSE: Hereditary angioedema (HAE) is a rare autosomal dominant life-threatening disease characterized by low levels of C1 inhibitor (type I HAE) or normal levels of ineffective C1 inhibitor (type II HAE), typically occurring as a consequence of a SERPING1 mutation. In some cases, a causal mutation remains undetected after using a standard molecular genetic analysis. RESULTS: Here we show a long methodological way to the final discovery of c.1029 + 384A > G, a novel deep intronic mutation in intron 6 which is responsible for HAE type I in a large family and has not been identified by a conventional diagnostic approach. This mutation results in de novo donor splice site creation and subsequent pseudoexon inclusion, the mechanism firstly described to occur in SERPING1 in this study. We additionally discovered that the proximal part of intron 6 is a region potentially prone to pseudoexon-activating mutations, since natural alternative exons and additional cryptic sites occur therein. Indeed, we confirmed the existence of at least two different alternative exons in this region not described previously. CONCLUSIONS: In conclusion, our results suggest that detecting aberrant transcripts, which are often low abundant because of nonsense-mediated decay, requires a modified methodological approach. We suggest SERPING1 intron 6 sequencing and/or tailored mRNA analysis to be routinely used in HAE patients with no mutation identified in the coding sequence.

• MeSH
• dítě MeSH
• dospělí MeSH
• exony genetika   MeSH
• hereditární angioedém, typy I a II genetika   MeSH
• inhibiční protein komplementu C1 genetika   MeSH
• introny genetika   MeSH
• lidé středního věku MeSH
• lidé MeSH
• místa sestřihu RNA genetika   MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mutace genetika   MeSH
• mutační analýza DNA metody   MeSH
• rodokmen MeSH
• senioři MeSH
• splicing proteinů genetika   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Genetic etiologies of chronic mucocutaneous candidiasis (CMC) disrupt human IL-17A/F-dependent immunity at mucosal surfaces, whereas those of connective tissue disorders (CTDs) often impair the TGF-β-dependent homeostasis of connective tissues. The signaling pathways involved are incompletely understood. We report a three-generation family with an autosomal dominant (AD) combination of CMC and a previously undescribed form of CTD that clinically overlaps with Ehlers-Danlos syndrome (EDS). The patients are heterozygous for a private splice-site variant of MAPK8, the gene encoding c-Jun N-terminal kinase 1 (JNK1), a component of the MAPK signaling pathway. This variant is loss-of-expression and loss-of-function in the patients' fibroblasts, which display AD JNK1 deficiency by haploinsufficiency. These cells have impaired, but not abolished, responses to IL-17A and IL-17F. Moreover, the development of the patients' TH17 cells was impaired ex vivo and in vitro, probably due to the involvement of JNK1 in the TGF-β-responsive pathway and further accounting for the patients' CMC. Consistently, the patients' fibroblasts displayed impaired JNK1- and c-Jun/ATF-2-dependent induction of key extracellular matrix (ECM) components and regulators, but not of EDS-causing gene products, in response to TGF-β. Furthermore, they displayed a transcriptional pattern in response to TGF-β different from that of fibroblasts from patients with Loeys-Dietz syndrome caused by mutations of TGFBR2 or SMAD3, further accounting for the patients' complex and unusual CTD phenotype. This experiment of nature indicates that the integrity of the human JNK1-dependent MAPK signaling pathway is essential for IL-17A- and IL-17F-dependent mucocutaneous immunity to Candida and for the TGF-β-dependent homeostasis of connective tissues.

• MeSH
• alely MeSH
• interleukin-17 imunologie   MeSH
• kandidóza chronická mukokutánní imunologie   MeSH
• kultivované buňky MeSH
• lidé MeSH
• mitogenem aktivovaná proteinkinasa 8 genetika   imunologie   metabolismus   MeSH
• mutace MeSH
• nemoci pojiva imunologie   MeSH
• transformující růstový faktor beta imunologie   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Splicing-affecting mutations can disrupt gene function by altering the transcript assembly. To ascertain splicing dysregulation principles, we modified a minigene assay for the parallel high-throughput evaluation of different mutations by next-generation sequencing. In our model system, all exonic and six intronic positions of the SMN1 gene's exon 7 were mutated to all possible nucleotide variants, which amounted to 180 unique single-nucleotide mutants and 470 double mutants. The mutations resulted in a wide range of splicing aberrations. Exonic splicing-affecting mutations resulted either in substantial exon skipping, supposedly driven by predicted exonic splicing silencer or cryptic donor splice site (5'ss) and de novo 5'ss strengthening and use. On the other hand, a single disruption of exonic splicing enhancer was not sufficient to cause major exon skipping, suggesting these elements can be substituted during exon recognition. While disrupting the acceptor splice site led only to exon skipping, some 5'ss mutations potentiated the use of three different cryptic 5'ss. Generally, single mutations supporting cryptic 5'ss use displayed better pre-mRNA/U1 snRNA duplex stability and increased splicing regulatory element strength across the original 5'ss. Analyzing double mutants supported the predominating splicing regulatory elements' effect, but U1 snRNA binding could contribute to the global balance of splicing isoforms. Based on these findings, we suggest that creating a new splicing enhancer across the mutated 5'ss can be one of the main factors driving cryptic 5'ss use.

• MeSH
• alternativní sestřih * MeSH
• buněčné linie MeSH
• exony * MeSH
• konformace nukleové kyseliny MeSH
• lidé MeSH
• místa sestřihu RNA MeSH
• mutace * MeSH
• mutageneze MeSH
• protein přežití motorických neuronů 1 chemie   genetika   metabolismus   MeSH
• RNA malá jaderná chemie   genetika   metabolismus   MeSH
• simulace molekulární dynamiky MeSH
• vazba proteinů MeSH
• výpočetní biologie metody   MeSH
• vysoce účinné nukleotidové sekvenování MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Pre-mRNA splicing is an essential step in gene expression, when introns are removed and exons joined by the complex of proteins called spliceosome. Correct splicing requires a precise exon/intron junction definition, which is determined by a consensual donor and acceptor splice site at the 5' and 3' end, respectively. An acceptor splice site (3'ss) consists of highly conserved AG nucleotides in positions E-2 and E-1. These nucleotides can appear in tandem, located 3 bp from each other. Then they are referred to as NAGNAG or tandem 3'ss, which can be alternatively spliced. NAG/TAG 3'ss motif abundance is extremely low and cannot be easily explained by just a nucleotide preference in this position. We tested artificial NAG/TAG motif's potential negative effect on exon recognition using a minigene assay. Introducing the NAG/TAG motif into seven different exons revealed no general negative effect on exon recognition. The only observed effect was the partial use of the newly formed distal 3'ss. We can conclude that this motif's extremely low preference in a natural 3'ss is not a consequence of the NAG/TAG motif's negative effect on exon recognition, but more likely the result of other RNA processing aspects, such as an alternative 3'ss choice, decreased 3'ss strength, or incorporating an amber stop codon.

• MeSH
• alternativní sestřih MeSH
• exony * MeSH
• HeLa buňky MeSH
• introny MeSH
• lidé MeSH
• místa sestřihu RNA genetika   fyziologie   MeSH
• nukleotidy genetika   MeSH
• sekvence nukleotidů MeSH
• sestřih RNA genetika   MeSH
• tandemové repetitivní sekvence MeSH
• terminační kodon MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Mutations in the C1 inhibitor (C1INH) encoding gene, SERPING1, are associated with hereditary angioedema (HAE) which manifests as recurrent submucosal and subcutaneous edema episodes. The major C1INH function is the complement system inhibition, preventing its spontaneous activation. The presented study is focused on SERPING1 exon 3, an alternative and extraordinarily long exon (499 bp). Endogenous expression analysis performed in the HepG2, human liver, and human peripheral blood cells revealed several exon 3 splicing variants alongside exon inclusion: a highly prevalent exon skipping variant and less frequent +38 and -15 variants with alternative 3' splice sites (ss) located 38 and 15 nucleotides downstream and upstream from the authentic 3' ss, respectively. An exon skipping variant introducing a premature stop codon, represented nearly one third of all splicing variants and surprisingly appeared not to be degraded by NMD. The alternative -15 3' ss was used to a small extent, although predicted to be extremely weak. Its use was shown to be independent of its strength and highly sensitive to any changes in the surrounding sequence. -15 3' ss seems to be co-regulated with the authentic 3' ss, whose use is dependent mainly on its strength and less on the presence of intronic regulatory motifs. Subtle SERPING1 exon 3 splicing regulation can contribute to overall C1INH plasma levels and HAE pathogenesis.

• MeSH
• alternativní sestřih genetika   MeSH
• buněčné jádro genetika   MeSH
• buňky Hep G2 MeSH
• exony genetika   MeSH
• inhibiční protein komplementu C1 genetika   MeSH
• lidé MeSH
• malá interferující RNA metabolismus   MeSH
• místa sestřihu RNA genetika   MeSH
• mutace genetika   MeSH
• nonsense mediated mRNA decay genetika   MeSH
• sekvence nukleotidů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• Publikační typ
• abstrakt z konference MeSH

For more than three decades, researchers have known that consensus splice sites alone are not sufficient regulatory elements to provide complex splicing regulation. Other regulators, so-called splicing regulatory elements (SREs) are needed. Most importantly, their sequence variants often underlie the development of various human disorders. However, due to their variable location and high degeneracy, these regulatory sequences are also very difficult to recognize and predict. Many different approaches aiming to identify SREs have been tried, often leading to the development of in silico prediction tools. While these tools were initially expected to be helpful to identify splicing-affecting mutations in genetic diagnostics, we are still quite far from meeting this goal. In fact, most of these tools are not able to accurately discern the SRE-affecting pathological variants from those not affecting splicing. Nonetheless, several recent evaluations have given appealing results (namely for EX-SKIP, ESRseq and Hexplorer predictors). In this review, we aim to summarize the history of the different approaches to SRE prediction, and provide additional validation of these tools based on patients' clinical data. Finally, we evaluate their usefulness for diagnostic settings and discuss the challenges that have yet to be met.

• MeSH
• diagnostické techniky molekulární metody   trendy   MeSH
• genetické nemoci vrozené * MeSH
• lidé MeSH
• místa sestřihu RNA * MeSH
• mutace * MeSH
• prekurzory RNA genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Both variants affecting splice sites and those in splicing regulatory elements (SREs) can impair pre-mRNA splicing, eventually leading to severe diseases. Despite the availability of many prediction tools, prognosis of splicing affection is not trivial, especially when SREs are involved. Here, we present data on 92 in silico-/55 minigene-analysed variants detected in genes responsible for the primary immunodeficiencies development (namely BTK, CD40LG, IL2RG, SERPING1, STAT3, and WAS). Of 20 splicing-affecting variants, 16 affected splice site while 4 disrupted potential SRE. The presence or absence of splicing defects was confirmed in 30 of 32 blood-derived patients' RNAs. Testing prediction tools performance, splice site disruptions and creations were reliably predicted in contrast to SRE-affecting variants for which just ESRseq, ΔHZEI-scores and EX-SKIP predictions showed promising results. Next, we found an interesting pattern in cryptic splice site predictions. These results might help PID-diagnosticians and geneticists cope with potential splicing-affecting variants.

• MeSH
• buňky Hep G2 MeSH
• dítě MeSH
• exony MeSH
• HeLa buňky MeSH
• kojenec MeSH
• komplement C1 - inaktivátory genetika   MeSH
• lidé MeSH
• messenger RNA genetika   MeSH
• mutace MeSH
• předškolní dítě MeSH
• protein Wiskottova-Aldrichova syndromu genetika   MeSH
• receptory interleukinů - společná gama-podjednotka genetika   MeSH
• rekombinantní fúzní proteiny genetika   MeSH
• sestřih RNA * MeSH
• syndromy imunologické nedostatečnosti genetika   MeSH
• transkripční faktor STAT3 genetika   MeSH
• tyrosinkinasy genetika   MeSH
• U937 buňky MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• předškolní dítě MeSH
• Publikační typ
• časopisecké články MeSH