RESUMEN
The dysregulation of alternative splicing (AS) is increasingly recognized as a pivotal player in the pathogenesis, progression, and treatment resistance of B-cell acute lymphoblastic leukemia (B-ALL). Despite its significance, the clinical implications of AS events in B-ALL remain largely unexplored. This study developed a prognostic model based on 18 AS events (18-AS), derived from a meticulous integration of bioinformatics methodologies and advanced machine learning algorithms. The 18-AS signature observed in B-ALL distinctly categorized patients into different groups with significant differences in immune infiltration, V(D)J rearrangement, drug sensitivity, and immunotherapy outcomes. Patients classified within the high 18-AS group exhibited lower immune infiltration scores, poorer chemo- and immune-therapy responses, and worse overall survival, underscoring the model's potential in refining therapeutic strategies. To validate the clinical applicability of the 18-AS, we established an SF-AS regulatory network and identified candidate drugs. More importantly, we conducted in vitro cell proliferation assays to confirm our analysis, demonstrating that the High-18AS cell line (SUP-B15) exhibited significantly enhanced sensitivity to Dasatinib, Dovitinib, and Midostaurin compared to the Low-18AS cell line (REH). These findings reveal AS events as novel prognostic biomarkers and therapeutic targets, advancing personalized treatment strategies in B-ALL management.
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Empalme Alternativo , Humanos , Empalme Alternativo/genética , Pronóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/tratamiento farmacológico , Femenino , Línea Celular Tumoral , Masculino , Biología Computacional/métodosRESUMEN
Caspase-2 (Casp-2) is an enzyme that regulates the development of apoptosis upon alternative splicing of its mRNA. The long form of Casp-2 (Casp-2L) promotes apoptosis while the short form (Casp-2S) has decreased enzymatic activity and inhibits the development of apoptotic processes. However, very little is known about the mechanism of Casp-2 alternative splicing. Several endonucleases are known to participate in this process. The aim of this study was to determine the role of EndoG in regulation of Casp-2 alternative splicing. Strong correlation between expression levels of EndoG and Casp-2 splice-variants was found in CD4⺠and CD8⺠human T lymphocytes. Such correlation increased after incubation of these cells with etoposide. Increased expression of Casp-2S was determined during EndoG over-expression in CD4⺠T-cells, after EndoG treatment of cell cytoplasm and nuclei and after nuclei incubation with EndoG digested cell RNA. Casp-2 alternative splicing was induced by a 60-mer RNA oligonucleotide in naked nuclei and in cells after transfection. The identified long non-coding RNA of 1016 nucleotides is the precursor of the 60-mer RNA oligonucleotide. Based on the results the following mechanism has been proposed. Casp-2 pre-mRNA is transcribed from the coding DNA strand while long non-coding RNA is transcribed from the template strand of the Casp-2 gene. EndoG digests long non-coding RNA and produces the 60-mer RNA oligonucleotide complementary to the Casp-2 pre-mRNA exon 9 and intron 9 junction place. Interaction of the 60-mer RNA oligonucleotide and Casp-2 pre-mRNA causes alternative splicing.
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Empalme Alternativo , Apoptosis , Linfocitos T CD4-Positivos , Caspasa 2 , Caspasa 2/metabolismo , Caspasa 2/genética , Humanos , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD8-positivos/metabolismo , Etopósido/farmacología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Endodesoxirribonucleasas/metabolismo , Endodesoxirribonucleasas/genética , Cisteína EndopeptidasasRESUMEN
BACKGROUND: Alternative splicing of pre-mRNA is a fundamental regulatory process in multicellular eukaryotes, significantly contributing to the diversification of the human proteome. RNA-binding fox-1 homologue 2 (RBFOX2), a member of the evolutionarily conserved RBFOX family, has emerged as a critical splicing regulator, playing a pivotal role in the alternative splicing of pre-mRNA. This review provides a comprehensive analysis of RBFOX2, elucidating its splicing activity through direct and indirect binding mechanisms. RBFOX2 exerts substantial influence over the alternative splicing of numerous transcripts, thereby shaping essential cellular processes such as differentiation and development. MAIN BODY OF THE ABSTRACT: Dysregulation of RBFOX2-mediated alternative splicing has been closely linked to a spectrum of cardiovascular diseases and malignant tumours, underscoring its potential as a therapeutic target. Despite significant progress, current research faces notable challenges. The complete structural characterisation of RBFOX2 remains elusive, limiting in-depth exploration beyond its RNA-recognition motif. Furthermore, the scarcity of studies focusing on RBFOX2-targeting drugs poses a hindrance to translating research findings into clinical applications. CONCLUSION: This review critically assesses the existing body of knowledge on RBFOX2, highlighting research gaps and limitations. By delineating these areas, this analysis not only serves as a foundational reference for future studies but also provides strategic insights for bridging these gaps. Addressing these challenges will be instrumental in unlocking the full therapeutic potential of RBFOX2, paving the way for innovative and effective treatments in various diseases.
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Neoplasias , Factores de Empalme de ARN , Humanos , Factores de Empalme de ARN/genética , Factores de Empalme de ARN/metabolismo , Neoplasias/genética , Neoplasias/metabolismo , Cardiomiopatías/genética , Cardiomiopatías/metabolismo , Proteínas Represoras/metabolismo , Proteínas Represoras/genética , Progresión de la Enfermedad , Empalme Alternativo/genética , Empalme del ARN/genéticaRESUMEN
BACKGROUND: Gene expression and alternative splicing are strictly regulated processes that shape brain development and determine the cellular identity of differentiated neural cell populations. Despite the availability of multiple valuable datasets, many functional implications, especially those related to alternative splicing, remain poorly understood. Moreover, neuroscientists working primarily experimentally often lack the bioinformatics expertise required to process alternative splicing data and produce meaningful and interpretable results. Notably, re-analyzing publicly available datasets and integrating them with in-house data can provide substantial novel insights. However, such analyses necessitate developing harmonized data handling and processing pipelines which in turn require considerable computational resources and in-depth bioinformatics expertise. RESULTS: Here, we present Cortexa-a comprehensive web portal that incorporates RNA-sequencing datasets from the mouse cerebral cortex (longitudinal or cell-specific) and the hippocampus. Cortexa facilitates understandable visualization of the expression and alternative splicing patterns of individual genes. Our platform provides SplicePCA-a tool that allows users to integrate their alternative splicing dataset and compare it to cell-specific or developmental neocortical splicing patterns. All standardized gene expression and alternative splicing datasets can be downloaded for further in-depth downstream analysis without the need for extensive preprocessing. CONCLUSIONS: Cortexa provides a robust and readily available resource for unraveling the complexity of gene expression and alternative splicing regulatory processes in the mouse brain. The data portal is available at https://cortexa-rna.com/.
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Empalme Alternativo , Encéfalo , Animales , Empalme Alternativo/genética , Ratones , Encéfalo/metabolismo , Biología Computacional/métodos , Programas Informáticos , Bases de Datos Genéticas , Análisis de Secuencia de ARN/métodos , Corteza Cerebral/metabolismo , Hipocampo/metabolismo , Perfilación de la Expresión Génica/métodosRESUMEN
The polyploid genome of cotton has significantly increased the transcript complexity. Recent advances in full-length transcript sequencing are now widely used to characterize the complete landscape of transcriptional events. Such studies in cotton can help us to explore the genetic mechanisms of the cotton seedling growth. Through long-read single-molecule RNA sequencing, this study compared the transcriptomes of three yield contrasting genotypes of upland cotton. Our analysis identified different numbers of spliced isoforms from 31,166, 28,716, and 28,713 genes in SJ48, Z98, and DT8 cotton genotypes, respectively, most of which were novel compared to previous cotton reference transcriptomes, and showed significant differences in the number of exon structures and coding sequence length due to intron retention. Quantification of isoform expression revealed significant differences in expression in the root and leaf of each genotype. An array of key isoform target genes showed protein kinase or phosphorylation functions, and their protein interaction network contained most of the circadian oscillator proteins. Spliced isoforms from the GIGANTEA (GI) protien were differentially regulated in each genotype and might be expected to regulate translational activities, including the sequence and function of target proteins. In addition, these spliced isoforms generate diurnal expression profiles in cotton leaves, which may alter the transcriptional regulatory network of seedling growth. Silencing of the novel spliced GI isoform Gh_A02G0645_N17 significantly affected biomass traits, contributed to variable growth, and increased transcription of the early flowering pathway gene ELF in cotton. Our high-throughput hybrid sequencing results will be useful to dissect functional differences among spliced isoforms in the polyploid cotton genome.
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Regulación de la Expresión Génica de las Plantas , Gossypium , Plantones , Gossypium/genética , Gossypium/crecimiento & desarrollo , Gossypium/metabolismo , Plantones/genética , Plantones/crecimiento & desarrollo , Plantones/metabolismo , Transcriptoma , Redes Reguladoras de Genes , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Empalme del ARN , Empalme Alternativo , Análisis de Secuencia de ARNRESUMEN
Signal transducer and activator of transcription 3 (STAT3) is a pleiotropic factor involved in multiple vital biological processes and a key mediator of gene transcription in response to cytokines, growth factors and aberrant activation of oncogenic signaling. STAT3 has two splicing isoforms, STAT3α and STAT3ß, derived from alternative splicing of exon 23 within pre-mRNA. STAT3ß differs from STAT3α by replacement of 55 amino-acid residues in the C-terminal transactivation domain with 7 specific amino acids. Thus, a shorter STAT3ß was originally regarded as a dominant negative isoform of STAT3α. Recently accumulating evidence from independent studies have shown STAT3 splicing isoforms confer distinct and overlapping functions in many fundamental cellular regulatory steps such as cell differentiation, inflammatory responses, and cancer progression. However, relatively little is known about the mechanisms of STAT3 pre-mRNA splicing, and it remains undiscovered which chemical compounds or bioactive substances can induce the STAT3ß expression. In this study, we generated a potent reporter for detection of alternative splicing of STAT3 pre-mRNA optimized for the screening of function-known chemical library, and successfully identified entinostat, a histone deacetylase inhibitor, as a novel inducer of STAT3ß through modulating mRNA splicing. Our findings demonstrate that alternative splicing of STAT3 can be regulated by a compound, providing an important clue for understanding the regulation mechanisms of the expression balance of STAT3 isoforms in a chemical biology approach. Entinostat is likely to be a promising seed compound for elucidating how the higher ratio of STAT3ß expression impacts on biological responses associated with Janus kinase (JAK)/STAT3 signaling pathway.
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Empalme Alternativo , Benzamidas , Piridinas , Precursores del ARN , Factor de Transcripción STAT3 , Factor de Transcripción STAT3/metabolismo , Factor de Transcripción STAT3/genética , Empalme Alternativo/efectos de los fármacos , Humanos , Precursores del ARN/genética , Precursores del ARN/metabolismo , Piridinas/farmacología , Benzamidas/farmacología , Inhibidores de Histona Desacetilasas/farmacología , Células HEK293 , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismoRESUMEN
Alzheimer's disease is the most common form of dementia, characterized by the pathological accumulation of amyloid-beta (Aß) plaques and tau neurofibrillary tangles. Triggering receptor expressed on myeloid cells 2 (TREM2) is increasingly recognized as playing a central role in Aß clearance and microglia activation in AD. The TREM2 gene transcriptional product is alternatively spliced to produce three different protein isoforms. The canonical TREM2 isoform binds to DAP12 to activate downstream pathways. However, little is known about the function or interaction partners of the alternative TREM2 isoforms. The present study utilized a computational approach in a systematic search for new interaction partners of the TREM2 isoforms by integrating several state-of-the-art structural bioinformatics tools from initial large-scale screening to one-on-one corroborative modeling and eventual all-atom visualization. CD9, a cell surface glycoprotein involved in cell-cell adhesion and migration, was identified as a new interaction partner for two TREM2 isoforms, and CALM, a calcium-binding protein involved in calcium signaling, was identified as an interaction partner for a third TREM2 isoform, highlighting the potential role of cell adhesion and calcium regulation in AD.
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Empalme Alternativo , Enfermedad de Alzheimer , Glicoproteínas de Membrana , Unión Proteica , Isoformas de Proteínas , Receptores Inmunológicos , Glicoproteínas de Membrana/metabolismo , Glicoproteínas de Membrana/genética , Humanos , Receptores Inmunológicos/metabolismo , Receptores Inmunológicos/genética , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/genética , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/genética , Biología Computacional/métodosRESUMEN
BACKGROUND: Alternative splicing is a pivotal mechanism of post-transcriptional modification that contributes to the transcriptome plasticity and proteome diversity in metazoan cells. Although many splicing regulations around the exon/intron regions are known, the relationship between promoter-bound transcription factors and the downstream alternative splicing largely remains unexplored. RESULTS: In this study, we present computational approaches to unravel the regulatory relationship between promoter-bound transcription factor binding sites (TFBSs) and the splicing patterns. We curated a fine dataset that includes DNase I hypersensitive site sequencing and transcriptomes across fifteen human tissues from ENCODE. Specifically, we proposed different representations of TF binding context and splicing patterns to examine the associations between the promoter and downstream splicing events. While machine learning models demonstrated potential in predicting splicing patterns based on TFBS occupancies, the limitations in the generalization of predicting the splicing forms of singleton genes across diverse tissues was observed with carefully examination using different cross-validation methods. We further investigated the association between alterations in individual TFBS at promoters and shifts in exon splicing efficiency. Our results demonstrate that the convolutional neural network (CNN) models, trained on TF binding changes in the promoters, can predict the changes in splicing patterns. Furthermore, a systemic in silico substitutions analysis on the CNN models highlighted several potential splicing regulators. Notably, using empirical validation using K562 CTCFL shRNA knock-down data, we showed the significant role of CTCFL in splicing regulation. CONCLUSION: In conclusion, our finding highlights the potential role of promoter-bound TFBSs in influencing the regulation of downstream splicing patterns and provides insights for discovering alternative splicing regulations.
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Empalme Alternativo , Aprendizaje Profundo , Regiones Promotoras Genéticas , Factores de Transcripción , Humanos , Sitios de Unión , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Biología Computacional/métodos , Exones/genéticaRESUMEN
BACKGROUND: Dysregulated splicing events are a common phenomenon in cancer with the Serine-arginine-rich splicing factor (SRSF) family emerging as pivotal regulators of gene expression, exerting influence over constitutive and alternative splicing processes. Although aberrations in a few SRSF family members have been implicated in various cancers, the comprehensive roles of other family constituents remain underexplored. METHODS: This study delves into the expression profile of the entire SRSF family (SRSF1-SRSF12) in 23 cancerous cell lines originating from diverse tissues using quantitative Real-Time PCR. Further, the transcript levels of the SRSF family were examined in oral cancer patient samples stratified into Pre-cancer (n = 15), Early cancer (n = 11), Late cancer (n = 14), and adjacent non-tumor tissues (n = 26) as controls. The results were corroborated by a parallel investigation utilizing the transcriptomics data of oral squamous cell carcinoma (OSCC) patients (n = 319) and controls (n = 35) available in The Cancer Genome Atlas (TCGA) database. RESULTS: Our investigation reveals a notable upregulation in the expression levels of key splicing factors, namely SRSF3, SRSF9, and SRSF10 in all oral cancer cell lines (SCC-4, UM-SCC-84, CAL33, SAS-H1). Conversely, no significant associations between SRSF family members and other cancer cell lines were discerned. Further, the expression profile of the SRSF family in oral cancer patient samples revealed significant upregulation of SRSF1, SRSF3, SRSF7, SRSF9, SRSF10, and SRSF11 in patients with late-stage oral cancer compared to controls. Transcriptomics data from TCGA database demonstrated remarkable upregulation of SRSF1, SRSF4, SRSF9, SRSF10, and SRSF11 in OSCC patients. CONCLUSION: Collectively our results underscore the critical involvement of SRSF family members in the context of oral cancer, highlighting their potential as key players in the altered splicing dynamics associated with cancer progression.
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Biomarcadores de Tumor , Regulación Neoplásica de la Expresión Génica , Neoplasias de la Boca , Factores de Empalme Serina-Arginina , Humanos , Neoplasias de la Boca/genética , Neoplasias de la Boca/patología , Neoplasias de la Boca/metabolismo , Factores de Empalme Serina-Arginina/genética , Factores de Empalme Serina-Arginina/metabolismo , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Línea Celular Tumoral , Femenino , Masculino , Empalme Alternativo , Persona de Mediana Edad , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patología , Perfilación de la Expresión GénicaRESUMEN
Alternative splicing (AS) in human genes is widely viewed as a mechanism for enhancing proteomic diversity. AS can also impact gene expression levels without increasing protein diversity by producing 'unproductive' transcripts that are targeted for rapid degradation by nonsense-mediated decay (NMD). However, the relative importance of this regulatory mechanism remains underexplored. To better understand the impact of AS-NMD relative to other regulatory mechanisms, we analyzed population-scale genomic data across eight molecular assays, covering various stages from transcription to cytoplasmic decay. We report threefold more unproductive splicing compared with prior estimates using steady-state RNA. This unproductive splicing compounds across multi-intronic genes, resulting in 15% of transcript molecules from protein-coding genes being unproductive. Leveraging genetic variation across cell lines, we find that GWAS trait-associated loci explained by AS are as often associated with NMD-induced expression level differences as with differences in protein isoform usage. Our findings suggest that much of the impact of AS is mediated by NMD-induced changes in gene expression rather than diversification of the proteome.
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Empalme Alternativo , Degradación de ARNm Mediada por Codón sin Sentido , Humanos , Empalme Alternativo/genética , Regulación de la Expresión Génica , Estudio de Asociación del Genoma Completo , Sitios de Carácter Cuantitativo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Intrones/genéticaRESUMEN
Single-cell multi-omics sequencing is a powerful approach to analyze complex mechanisms underlying neuronal development and regeneration. However, current methods lack the ability to simultaneously profile RNA alternative splicing and chromatin accessibility at the single-cell level. We develop a technique, single-cell RNA isoform and chromatin accessibility sequencing (scRICA-seq), which demonstrates higher sensitivity and cost-effectiveness compared to existing methods. scRICA-seq can profile both isoforms and chromatin accessibility for up to 10,000 single cells in a single run. Applying this method to human retinal organoids, we construct a multi-omic cell atlas and reveal associations between chromatin accessibility, isoform expression of fate-determining factors, and alternative splicing events in their binding sites. This study provides insights into integrating epigenetics, transcription, and RNA splicing to elucidate the mechanisms underlying retinal neuronal development and fate determination.
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Cromatina , Organoides , Retina , Análisis de la Célula Individual , Humanos , Organoides/metabolismo , Organoides/citología , Cromatina/metabolismo , Cromatina/genética , Retina/metabolismo , Retina/citología , Análisis de la Célula Individual/métodos , Empalme Alternativo , ARN/metabolismo , ARN/genética , Análisis de Secuencia de ARN/métodos , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/genéticaRESUMEN
BACKGROUND: Periostin (POSTN) is a type of matrix protein that functions by binding to other matrix proteins, cell surface receptors, or other molecules, such as cytokines and proteases. POSTN has four major splicing variants (PN1-4), which are primarily expressed in fibroblasts and cancer. We have reported that we should inhibit pathological POSTN (PN1-3), but not physiological POSTN (PN4). In particular, pathological POSTN with exon 17 is present in both stroma and cancer, but it is unclear whether the stroma or cancer pathological POSTN should be suppressed. METHODS AND RESULTS: We transplanted 4T1 cells (breast cancer) secreting POSTN with exon 17 into 17KO mice lacking POSTN exon 17 to suppress stromal POSTN with exon 17. The results show that 17KO mice had smaller primary tumors and fewer metastases. Furthermore, to suppress cancer POSTN with exon 17, 4T1 cells transfected with POSTN exon 17 skipping oligo or control oligo were transplanted from the tail vein into the lungs. The results show that POSTN exon 17 skipping oligo significantly suppressed lung metastasis. CONCLUSIONS: These findings suggest that it is important to suppress POSTN exon 17 in both stroma and cancer. Antibody targeting POSTN exon 17 may be a therapeutic candidate for breast cancer.
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Moléculas de Adhesión Celular , Exones , Células del Estroma , Animales , Moléculas de Adhesión Celular/metabolismo , Moléculas de Adhesión Celular/genética , Exones/genética , Ratones , Femenino , Línea Celular Tumoral , Células del Estroma/metabolismo , Células del Estroma/patología , Humanos , Empalme Alternativo/genética , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Neoplasias de la Mama/metabolismo , Ratones Noqueados , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/secundario , Neoplasias Pulmonares/metabolismo , Ratones Endogámicos BALB C , PeriostinaRESUMEN
MDM4 is upregulated in the majority of melanoma cases and has been described as a "key therapeutic target in cutaneous melanoma". Numerous isoforms of MDM4 exist, with few studies examining their specific expression in human tissues. The changes in splicing of MDM4 during human melanomagenesis are critical to p53 activity and represent potential therapeutic targets. Compounding this, studies relying on short reads lose "connectivity" data, so full transcripts are frequently only inferred from the presence of splice junction reads. To address this problem, long-read nanopore sequencing was utilized to read the entire length of transcripts. Here, MDM4 transcripts, both alternative and canonical, are characterized in a pilot cohort of human melanoma specimens. RT-PCR was first used to identify the presence of novel splice junctions in these specimens. RT-qPCR then quantified the expression of major MDM4 isoforms observed during sequencing. The current study both identifies and quantifies MDM4 isoforms present in melanoma tumor samples. In the current study, we observed high expression levels of MDM4-S, MDM4-FL, MDM4-A, and the previously undescribed Ensembl transcript MDM4-209. A novel transcript lacking both exons 6 and 9 is observed and named MDM4-A/S for its resemblance to both MDM4-A and MDM4-S isoforms.
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Melanoma , Isoformas de Proteínas , Humanos , Melanoma/genética , Melanoma/patología , Melanoma/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patología , Neoplasias Cutáneas/metabolismo , Empalme Alternativo , Regulación Neoplásica de la Expresión Génica , Secuenciación de Nanoporos/métodosRESUMEN
The contribution of splicing variants to molecular diagnostics of inherited diseases is reported to be less than 10%. This figure is likely an underestimation due to several factors including difficulty in predicting the effect of such variants, the need for functional assays, and the inability to detect them (depending on their locations and the sequencing technology used). The aim of this study was to assess the utility of Nanopore sequencing in characterizing and quantifying aberrant splicing events. For this purpose, we selected 19 candidate splicing variants that were identified in patients affected by inherited retinal dystrophies. Several in silico tools were deployed to predict the nature and estimate the magnitude of variant-induced aberrant splicing events. Minigene assay or whole blood-derived cDNA was used to functionally characterize the variants. PCR amplification of minigene-specific cDNA or the target gene in blood cDNA, combined with Nanopore sequencing, was used to identify the resulting transcripts. Thirteen out of nineteen variants caused aberrant splicing events, including cryptic splice site activation, exon skipping, pseudoexon inclusion, or a combination of these. Nanopore sequencing allowed for the identification of full-length transcripts and their precise quantification, which were often in accord with in silico predictions. The method detected reliably low-abundant transcripts, which would not be detected by conventional strategies, such as RT-PCR followed by Sanger sequencing.
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Secuenciación de Nucleótidos de Alto Rendimiento , Secuenciación de Nanoporos , Distrofias Retinianas , Humanos , Distrofias Retinianas/genética , Distrofias Retinianas/diagnóstico , Secuenciación de Nanoporos/métodos , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Empalme Alternativo/genética , Empalme del ARN/genética , Exones/genéticaRESUMEN
Heart failure (HF) is associated with global changes in gene expression. Alternative mRNA splicing (AS) is a key regulatory mechanism underlying these changes. However, the whole status of molecules involved in the splicing process in human HF is unknown. Therefore, we analysed the spliceosome transcriptome in cardiac tissue (n = 36) from control subjects and HF patients (with ischaemic (ICM) and dilated (DCM) cardiomyopathies) using RNA-seq. We found greater deregulation of spliceosome machinery in ICM. Specifically, we showed widespread upregulation of the E and C complex components, highlighting an increase in SNRPD2 (FC = 1.35, p < 0.05) and DHX35 (FC = 1.34, p < 0.001) mRNA levels. In contrast, we observed generalised downregulation of the A complex and cardiac-specific AS factors, such as the multifunctional protein PCBP2 (FC = -1.29, p < 0.001) and the RNA binding proteins QKI (FC = -1.35, p < 0.01). In addition, we found a relationship between SNPRD2 (an E complex component) and the left ventricular mass index in ICM patients (r = 0.779; p < 0.01). On the other hand, we observed the specific underexpression of DDX46 (FC = -1.29), RBM17 (FC = -1.33), SDE2 (FC = -1.35) and RBFOX1 (FC = -1.33), p < 0.05, in DCM patients. Therefore, these aetiology-related alterations may indicate the differential involvement of the splicing process in the development of ICM and DCM.
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Empalme Alternativo , Insuficiencia Cardíaca , Factores de Empalme de ARN , Empalmosomas , Transcriptoma , Humanos , Empalmosomas/metabolismo , Empalmosomas/genética , Insuficiencia Cardíaca/genética , Insuficiencia Cardíaca/metabolismo , Masculino , Femenino , Persona de Mediana Edad , Factores de Empalme de ARN/metabolismo , Factores de Empalme de ARN/genética , Anciano , Cardiomiopatía Dilatada/genética , Cardiomiopatía Dilatada/metabolismo , Miocardio/metabolismo , Miocardio/patología , Perfilación de la Expresión Génica , Proteínas de Unión al ARN/metabolismo , Proteínas de Unión al ARN/genéticaRESUMEN
PURPOSE: Genetic hypomorphic defects in X chromosomal IKBKG coding for the NF-κB essential modulator (NEMO) lead to ectodermal dysplasia and immunodeficiency in males and the skin disorder incontinentia pigmenti (IP) in females, respectively. NF-κB essential modulator (NEMO) Δ-exon 5-autoinflammatory syndrome (NEMO-NDAS) is a systemic autoinflammatory disease caused by alternative splicing and increased proportion of NEMO-Δex5. We investigated a female carrier presenting with IP and NEMO-NDAS due to non-skewed X-inactivation. METHODS: IKBKG transcripts were quantified in peripheral blood mononuclear cells isolated from the patient, her mother, and healthy controls using RT-PCR and nanopore sequencing. Corresponding proteins were analyzed by western blotting and flow cytometry. Besides toll-like receptor (TLR) and tumor necrosis factor (TNF) signaling, the interferon signature, cytokine production and X-inactivation status were investigated. RESULTS: IP and autoinflammation with recurrent fever, oral ulcers, hepatitis, and neutropenia, but no immunodeficiency was observed in a female patient. Besides moderately reduced NEMO signaling function, type I interferonopathy, and elevated IL-18 and CXCL10 were found. She and her mother both carried the heterozygous variant c.613 C > T p.(Gln205*) in exon 5 of IKBKG previously reported in NEMO-deficient patients. However, X-inactivation was skewed in the mother, but not in the patient. Alternative splicing led to increased ratios of NEMO-Dex5 over full-length protein in peripheral blood cell subsets causing autoinflammation. Clinical symptoms partially resolved under treatment with TNF inhibitors. CONCLUSION: Non-skewed X-inactivation can lead to NEMO-NDAS in females with IP carrying hypomorphic IKBKG variants due to alternative splicing and increased proportions of NEMO-∆ex5.
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Exones , Quinasa I-kappa B , Incontinencia Pigmentaria , Inactivación del Cromosoma X , Humanos , Femenino , Incontinencia Pigmentaria/genética , Incontinencia Pigmentaria/diagnóstico , Quinasa I-kappa B/genética , Exones/genética , Enfermedades Autoinflamatorias Hereditarias/genética , Enfermedades Autoinflamatorias Hereditarias/diagnóstico , Mutación/genética , Citocinas/metabolismo , Adulto , Empalme Alternativo , Transducción de SeñalRESUMEN
The C-terminal domain of RPB1 (CTD) orchestrates transcription by recruiting regulators to RNA Pol II upon phosphorylation. With CTD driving condensate formation on gene loci, the molecular mechanism behind how CTD-mediated recruitment of transcriptional regulators influences condensates formation remains unclear. Our study unveils that phosphorylation reversibly dissolves phase separation induced by the unphosphorylated CTD. Phosphorylated CTD, upon specific association with transcription regulators, forms distinct condensates from unphosphorylated CTD. Functional studies demonstrate CTD variants with diverse condensation properties exhibit differences in promoter binding and mRNA co-processing in cells. Notably, varying CTD lengths influence the assembly of RNA processing machinery and alternative splicing outcomes, which in turn affects cellular growth, linking the evolution of CTD variation/length with the complexity of splicing from yeast to human. These findings provide compelling evidence for a model wherein post-translational modification enables the transition of functionally specialized condensates, highlighting a co-evolution link between CTD condensation and splicing.
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Empalme Alternativo , ARN Polimerasa II , Saccharomyces cerevisiae , Transcripción Genética , ARN Polimerasa II/metabolismo , ARN Polimerasa II/genética , Fosforilación , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Humanos , Dominios Proteicos , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , ARN Mensajero/metabolismo , ARN Mensajero/genética , Regiones Promotoras Genéticas , Procesamiento Proteico-PostraduccionalRESUMEN
Gustavus, a positive regulator in arthropod reproduction, features a conserved SPRY and a C-terminal SOCS box domain and belongs to the SPSB protein family. The SPSB family, encompassing SPSB1 to SPSB4, plays pivotal roles in higher animals, including immune response, apoptosis, growth, and stress responses. In Neocaridina denticulata sinensis, alternative splicing yielded two NdGustavus isoforms, NdGusX1 and NdGusX2, with distinct expression patterns-high in ovaries and muscles, respectively, and across all ovarian germ cells. These isoforms showed similar expression dynamics during embryogenesis and significant upregulation post-copper ion exposure (P < 0.05). The in situ hybridization result elucidated that NdGusX1 and NdGusX2 were expressed across the germ cell spectrum in the ovary, with NdGusX1 showing enhanced expression in oogonia and primary oocytes. In addition, RNA interference revealed functional complementation in ovaries and potential functional differentiation in muscles. Knockdown of NdGusX1 and NdGusX2 potentially disrupted endogenous vitellogenin synthesis, regulating vitellogenesis and reducing mature oocyte volume, affecting follicular cavity occupation. This study provides a theoretical framework for understanding the biological functions of the SPSB family in crustacean ovarian maturation.
Asunto(s)
Empalme Alternativo , Ovario , Animales , Femenino , Ovario/metabolismo , Ovario/crecimiento & desarrollo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Oocitos/metabolismo , Vitelogénesis/genética , Regulación del Desarrollo de la Expresión GénicaRESUMEN
SRSF2 plays a dual role, functioning both as a transcriptional regulator and a key player in alternative splicing. The absence of Srsf2 in MyoD + progenitors resulted in perinatal mortality in mice, accompanied by severe skeletal muscle defects. SRSF2 deficiency disrupts the directional migration of MyoD progenitors, causing them to disperse into both muscle and non-muscle regions. Single-cell RNA-sequencing analysis revealed significant alterations in Srsf2-deficient myoblasts, including a reduction in extracellular matrix components, diminished expression of genes involved in ameboid-type cell migration and cytoskeleton organization, mitosis irregularities, and premature differentiation. Notably, one of the targets regulated by Srsf2 is the serine/threonine kinase Aurka. Knockdown of Aurka led to reduced cell proliferation, disrupted cytoskeleton, and impaired differentiation, reflecting the effects seen with Srsf2 knockdown. Crucially, the introduction of exogenous Aurka in Srsf2-knockdown cells markedly alleviated the differentiation defects caused by Srsf2 knockdown. Furthermore, our research unveiled the role of Srsf2 in controlling alternative splicing within genes associated with human skeletal muscle diseases, such as BIN1, DMPK, FHL1, and LDB3. Specifically, the precise knockdown of the Bin1 exon17-containing variant, which is excluded following Srsf2 depletion, profoundly disrupted C2C12 cell differentiation. In summary, our study offers valuable insights into the role of SRSF2 in governing MyoD progenitors to specific muscle regions, thereby controlling their differentiation through the regulation of targeted genes and alternative splicing during skeletal muscle development.
Asunto(s)
Diferenciación Celular , Movimiento Celular , Desarrollo de Músculos , Músculo Esquelético , Proteína MioD , Factores de Empalme Serina-Arginina , Animales , Ratones , Factores de Empalme Serina-Arginina/metabolismo , Factores de Empalme Serina-Arginina/genética , Desarrollo de Músculos/genética , Músculo Esquelético/metabolismo , Músculo Esquelético/crecimiento & desarrollo , Proteína MioD/metabolismo , Proteína MioD/genética , Aurora Quinasa A/metabolismo , Aurora Quinasa A/genética , Mioblastos/metabolismo , Empalme AlternativoRESUMEN
T cell receptor (TCR) sensitivity to peptide-major histocompatibility complex (MHC) dictates T cell fate. Canonical models of TCR sensitivity cannot be fully explained by transcriptional regulation. In this work, we identify a posttranscriptional regulatory mechanism of TCR sensitivity that guides alternative splicing of TCR signaling transcripts through an evolutionarily ultraconserved poison exon (PE) in the RNA-binding protein (RBP) TRA2ß in mouse and human. TRA2ß-PE splicing, seen during cancer and infection, was required for TCR-induced effector T cell expansion and function. Tra2ß-PE skipping enhanced T cell response to antigen by increasing TCR sensitivity. As antigen levels decreased, Tra2ß-PE reinclusion allowed T cell survival. Finally, we found that TRA2ß-PE was first included in the genome of jawed vertebrates that were capable of TCR gene rearrangements. We propose that TRA2ß-PE splicing acts as a gatekeeper of TCR sensitivity to shape T cell fate.