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1.
Sci Adv ; 10(26): eadl1049, 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38924416

RESUMO

A long-standing goal of evolutionary biology is to decode how changes in gene regulatory networks contribute to human-specific traits. Human accelerated regions (HARs) are prime candidates for driving gene regulatory modifications in human development. The RBFOX1 locus is densely populated with HARs, providing a set of potential regulatory elements that could have changed its expression in the human lineage. Here, we examined the role of RBFOX1-HARs using transgenic zebrafish reporter assays and identified 15 transcriptional enhancers that are active in the developing nervous system, 9 of which displayed differential activity between the human and chimpanzee sequences. The engineered loss of two selected RBFOX1-HARs in knockout mouse models modified Rbfox1 expression at specific developmental stages and tissues in the brain, influencing the expression and splicing of a high number of Rbfox1 target genes. Our results provided insight into the spatial and temporal changes in gene expression driven by RBFOX1-HARs.


Assuntos
Elementos Facilitadores Genéticos , Evolução Molecular , Fatores de Processamento de RNA , Peixe-Zebra , Humanos , Animais , Fatores de Processamento de RNA/genética , Fatores de Processamento de RNA/metabolismo , Peixe-Zebra/genética , Camundongos , Regulação da Expressão Gênica no Desenvolvimento , Camundongos Knockout , Animais Geneticamente Modificados , Redes Reguladoras de Genes , Pan troglodytes/genética , Loci Gênicos
2.
Viruses ; 16(6)2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38932230

RESUMO

Type I interferons (IFN-Is) are pivotal in innate immunity against human immunodeficiency virus I (HIV-1) by eliciting the expression of IFN-stimulated genes (ISGs), which encompass potent host restriction factors. While ISGs restrict the viral replication within the host cell by targeting various stages of the viral life cycle, the lesser-known IFN-repressed genes (IRepGs), including RNA-binding proteins (RBPs), affect the viral replication by altering the expression of the host dependency factors that are essential for efficient HIV-1 gene expression. Both the host restriction and dependency factors determine the viral replication efficiency; however, the understanding of the IRepGs implicated in HIV-1 infection remains greatly limited at present. This review provides a comprehensive overview of the current understanding regarding the impact of the RNA-binding protein families, specifically the two families of splicing-associated proteins SRSF and hnRNP, on HIV-1 gene expression and viral replication. Since the recent findings show specifically that SRSF1 and hnRNP A0 are regulated by IFN-I in various cell lines and primary cells, including intestinal lamina propria mononuclear cells (LPMCs) and peripheral blood mononuclear cells (PBMCs), we particularly discuss their role in the context of the innate immunity affecting HIV-1 replication.


Assuntos
Infecções por HIV , HIV-1 , Imunidade Inata , Replicação Viral , HIV-1/genética , HIV-1/fisiologia , Humanos , Infecções por HIV/virologia , Infecções por HIV/genética , Infecções por HIV/imunologia , Regulação Viral da Expressão Gênica , Fatores de Processamento de RNA/metabolismo , Fatores de Processamento de RNA/genética , Interferon Tipo I/metabolismo , Interferon Tipo I/genética , Interações Hospedeiro-Patógeno/imunologia , Interações Hospedeiro-Patógeno/genética , Interferons/metabolismo , Interferons/genética , Interferons/imunologia , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo
3.
Discov Med ; 36(185): 1289-1297, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38926115

RESUMO

BACKGROUND: Genetic mutations play a crucial role in the development and progression of myelodysplastic syndromes (MDS), impacting the immune microenvironment and influencing the choice of treatment regimen, as well as the efficacy and prognosis of patients. The objective of this study was to examine variations in hematological and immunological characteristics associated with common gene mutations in MDS patients and establish a foundation for the precise treatment of MDS. METHODS: The hematological, immunological, and other clinical features of 71 recently diagnosed MDS patients from January 1, 2019, to July 31, 2023, were retrospectively analyzed. These patients were categorized based on their gene mutations, and the variances in hematological and immunological characteristics among distinct groups were compared. RESULTS: Hematological variances were observed among different gene mutation groups. Specifically, platelet counts in the splicing factor 3B subunit 1 (SF3B1) mutation group were notably higher compared to the wild-type group (p = 0.009). Conversely, in the additional sex combs like 1 (ASXL1) mutation groups, monocyte ratios were significantly elevated in comparison to the wild-type group (p = 0.046), and in the ten-eleven translocation 2 (TET2) mutation group, lymphocyte ratios were significantly lower (p = 0.022). Additionally, the leukocyte (p = 0.005), neutrophil ratio (p = 0.002), and lymphocyte ratio (p = 0.001) were significantly higher in the Runt-related transcription factor 1 (RUNX1) mutation group. Regarding immunological distinctions, the Natural Killer (NK) cell ratio demonstrated a significant increase in the SF3B1 mutation group (p = 0.005). Moreover, the TET2 mutation group exhibited a significantly higher Interleukin-8 (IL-8) level (p = 0.017). In contrast, the U2 small nuclear RNA auxiliary factor 1 (U2AF1) group displayed significantly lower levels of IL-1ß (p = 0.033), IL-10 (p = 0.033), and Tumour Necrosis Factor-α (TNF-α) (p = 0.009). CONCLUSION: Distinct variations exist in the immune microenvironment of MDS associated with different genetic mutations. Further studies are imperative to delve into the underlying mechanisms that drive these differences.


Assuntos
Dioxigenases , Mutação , Síndromes Mielodisplásicas , Fatores de Processamento de RNA , Humanos , Síndromes Mielodisplásicas/genética , Síndromes Mielodisplásicas/imunologia , Síndromes Mielodisplásicas/sangue , Feminino , Masculino , Pessoa de Meia-Idade , Idoso , Fatores de Processamento de RNA/genética , Estudos Retrospectivos , Adulto , Idoso de 80 Anos ou mais , Proteínas de Ligação a DNA/genética , Fosfoproteínas/genética , Fosfoproteínas/imunologia , Células Matadoras Naturais/imunologia , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Contagem de Plaquetas , Proteínas Repressoras
4.
Genes (Basel) ; 15(6)2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38927612

RESUMO

The current investigation endeavors to identify differentially expressed alternatively spliced (DAS) genes that exhibit concordant expression with splicing factors (SFs) under diverse multifactorial abiotic stress combinations in Arabidopsis seedlings. SFs serve as the post-transcriptional mechanism governing the spatiotemporal dynamics of gene expression. The different stresses encompass variations in salt concentration, heat, intensive light, and their combinations. Clusters demonstrating consistent expression profiles were surveyed to pinpoint DAS/SF gene pairs exhibiting concordant expression. Through rigorous selection criteria, which incorporate alignment with documented gene functionalities and expression patterns observed in this study, four members of the serine/arginine-rich (SR) gene family were delineated as SFs concordantly expressed with six DAS genes. These regulated SF genes encompass cactin, SR1-like, SR30, and SC35-like. The identified concordantly expressed DAS genes encode diverse proteins such as the 26.5 kDa heat shock protein, chaperone protein DnaJ, potassium channel GORK, calcium-binding EF hand family protein, DEAD-box RNA helicase, and 1-aminocyclopropane-1-carboxylate synthase 6. Among the concordantly expressed DAS/SF gene pairs, SR30/DEAD-box RNA helicase, and SC35-like/1-aminocyclopropane-1-carboxylate synthase 6 emerge as promising candidates, necessitating further examinations to ascertain whether these SFs orchestrate splicing of the respective DAS genes. This study contributes to a deeper comprehension of the varied responses of the splicing machinery to abiotic stresses. Leveraging these DAS/SF associations shows promise for elucidating avenues for augmenting breeding programs aimed at fortifying cultivated plants against heat and intensive light stresses.


Assuntos
Processamento Alternativo , Proteínas de Arabidopsis , Arabidopsis , Regulação da Expressão Gênica de Plantas , Estresse Fisiológico , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Estresse Fisiológico/genética , Plântula/genética , Fatores de Processamento de RNA/genética , Fatores de Processamento de RNA/metabolismo
5.
Cell Mol Life Sci ; 81(1): 276, 2024 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-38909325

RESUMO

N6-methyladenosine (m6A) is one of the most prevalent and conserved RNA modifications. It controls several biological processes, including the biogenesis and function of circular RNAs (circRNAs), which are a class of covalently closed-single stranded RNAs. Several studies have revealed that proteotoxic stress response induction could be a relevant anticancer therapy in Acute Myeloid Leukemia (AML). Furthermore, a strong molecular interaction between the m6A mRNA modification factors and the suppression of the proteotoxic stress response has emerged. Since the proteasome inhibition leading to the imbalance in protein homeostasis is strictly linked to the stress response induction, we investigated the role of Bortezomib (Btz) on m6A regulation and in particular its impact on the modulation of m6A-modified circRNAs expression. Here, we show that treating AML cells with Btz downregulated the expression of the m6A regulator WTAP at translational level, mainly because of increased oxidative stress. Indeed, Btz treatment promoted oxidative stress, with ROS generation and HMOX-1 activation and administration of the reducing agent N-acetylcysteine restored WTAP expression. Additionally, we identified m6A-modified circRNAs modulated by Btz treatment, including circHIPK3, which is implicated in protein folding and oxidative stress regulation. These results highlight the intricate molecular networks involved in oxidative and ER stress induction in AML cells following proteotoxic stress response, laying the groundwork for future therapeutic strategies targeting these pathways.


Assuntos
Adenosina , Leucemia Mieloide Aguda , Estresse Oxidativo , RNA Circular , Humanos , RNA Circular/genética , RNA Circular/metabolismo , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/tratamento farmacológico , Adenosina/análogos & derivados , Adenosina/metabolismo , Adenosina/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Bortezomib/farmacologia , Linhagem Celular Tumoral , Espécies Reativas de Oxigênio/metabolismo , Fatores de Processamento de RNA/metabolismo , Fatores de Processamento de RNA/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/patologia , Heme Oxigenase-1/metabolismo , Heme Oxigenase-1/genética , Proteínas Serina-Treonina Quinases , Peptídeos e Proteínas de Sinalização Intracelular
6.
Int J Biol Sci ; 20(8): 3173-3184, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38904016

RESUMO

Pancreatic ductal adenocarcinoma (PDAC) poses significant challenges in terms of prognosis and treatment. Recent research has identified splicing deregulation as a new cancer hallmark. Herein, we investigated the largely uncharacterized alternative splicing profile and the key splicing factor SF3B1 in PDAC pancreatic cells and tissues as a potential discovery source of plausible drug targets and new predictive biomarkers of clinical outcome. The research involved a transcriptome-wide analysis, comparing profiles of splicing profiles in PDAC primary cells with normal ductal cells. This revealed more than 400 significant differential splicing events in genes involved in regulation of gene expression, primarily related to mRNA splicing, and metabolism of nucleic acids. PDAC cultures were highly sensitive to the SF3B1 modulators, E7107 and Pladienolide-B, showing IC50s in the low nanomolar range. These compounds induced apoptosis, associated to induction of the MCL-1/S splice variant. and reduced cell migration, associated to RON mis-splicing. In an orthotopic mouse model, E7107 showed promising results. Furthermore, we evaluated SF3B1 expression in specimens from 87 patients and found a significant association of SF3B1 expression with progression-free and overall survival. In conclusion, SF3B1 emerges as both a potential prognostic factor and therapeutic target in PDAC, impacting cell proliferation, migration, and apoptosis. These findings warrant future studies on this new therapeutic strategy against PDAC.


Assuntos
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Fatores de Processamento de RNA , Humanos , Fatores de Processamento de RNA/metabolismo , Fatores de Processamento de RNA/genética , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/tratamento farmacológico , Animais , Camundongos , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral , Compostos de Epóxi/farmacologia , Compostos de Epóxi/uso terapêutico , Prognóstico , Fosfoproteínas/metabolismo , Fosfoproteínas/genética , Macrolídeos/uso terapêutico , Macrolídeos/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/genética , Splicing de RNA , Processamento Alternativo , Feminino , Movimento Celular/genética
7.
Leukemia ; 38(6): 1334-1341, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38714876

RESUMO

We investigated data from 180 consecutive patients with myelodysplastic/myeloproliferative neoplasms with SF3B1 mutation and thrombocytosis (MDS/MPN-SF3B1-T) who were diagnosed according to the 2022 World Health Organization (WHO) classification of myeloid neoplasms to identify covariates associated with survival. At a median follow-up of 48 months (95% confidence interval [CI] 35-61 months), the median survival was 69 months (95% CI 59-79 months). Patients with bone marrow ring sideroblasts (RS) < 15% had shorter median overall survival (OS) than did those with bone marrow RS ≥ 15% (41 months [95% CI 32-50 months] versus 76 months [95% CI 59-93 months]; P < 0.001). According to the univariable analyses of OS, age ≥ 65 years (P < 0.001), hemoglobin concentration (Hb) < 80 g/L (P = 0.090), platelet count (PLT) ≥ 800 × 10E + 9/L (P = 0.087), bone marrow RS < 15% (P < 0.001), the Revised International Prognostic Scoring System (IPSS-R) cytogenetic category intermediate/poor/very poor (P = 0.005), SETBP1 mutation (P = 0.061) and SRSF2 mutation (P < 0.001) were associated with poor survival. Based on variables selected from univariable analyses, two separate survival prediction models, a clinical survival model, and a clinical-molecular survival model, were developed using multivariable analyses with the minimum value of the Akaike information criterion (AIC) to specifically predict outcomes in patients with MDS/MPN-SF3B1-T according to the 2022 WHO classification.


Assuntos
Mutação , Doenças Mieloproliferativas-Mielodisplásicas , Fosfoproteínas , Fatores de Processamento de RNA , Trombocitose , Humanos , Fatores de Processamento de RNA/genética , Masculino , Feminino , Trombocitose/genética , Idoso , Fosfoproteínas/genética , Pessoa de Meia-Idade , Doenças Mieloproliferativas-Mielodisplásicas/genética , Doenças Mieloproliferativas-Mielodisplásicas/mortalidade , Doenças Mieloproliferativas-Mielodisplásicas/patologia , Prognóstico , Idoso de 80 Anos ou mais , Adulto , Taxa de Sobrevida , Seguimentos , Síndromes Mielodisplásicas/genética , Síndromes Mielodisplásicas/mortalidade , Síndromes Mielodisplásicas/patologia , Fatores de Processamento de Serina-Arginina/genética
8.
Cancer Treat Rev ; 128: 102768, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38797062

RESUMO

Small cell lung cancer (SCLC) is characterized by a dismal prognosis. Many efforts have been made so far for identifying novel biomarkers for a personalized treatment for SCLC patients. Schlafen 11 (SLFN11) is a protein differently expressed in many cancers and recently emerged as a new potential biomarker. Lower expression of SLFN11 correlates with a worse prognosis in SCLC and other tumors. SLFN11 has a role in tumorigenesis, inducing replication arrest in the presence of DNA damage through the block of the replication fork. SLFN11 interacts also with chromatin accessibility, proteotoxic stress and mammalian target of rapamycin signalling pathway. The expression of SLFN11 is regulated by epigenetic mechanisms, including promoter methylation, histone deacetylation, and the histone methylation. The downregulation of SLFN11 correlates with a worse response to topoisomerase I and II inhibitors, alkylating agents, and poly ADP-ribose polymerase inhibitors in different cancer types. Some studies exploring strategies for overcoming drug resistance in tumors with low levels of SLFN11 showed promising results. One of these strategies includes the interaction with the Ataxia Telangiectasia and Rad3-related pathway, constitutively activated and leading to cell survival and tumor growth in the presence of low levels of SLFN11. Furthermore, the expression of SLFN11 is dynamic through time and different anticancer therapy and liquid biopsy seems to be an attractive tool for catching SLFN11 different expressions. Despite this, further investigations exploring SLFN11 as a predictive biomarker, its longitudinal changes, and new strategies to overcome drug resistances are needed.


Assuntos
Neoplasias Pulmonares , Carcinoma de Pequenas Células do Pulmão , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/metabolismo , Carcinoma de Pequenas Células do Pulmão/tratamento farmacológico , Carcinoma de Pequenas Células do Pulmão/genética , Carcinoma de Pequenas Células do Pulmão/patologia , Carcinoma de Pequenas Células do Pulmão/metabolismo , Biomarcadores Tumorais/metabolismo , Biomarcadores Tumorais/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Antineoplásicos/uso terapêutico , Antineoplásicos/farmacologia , Fatores de Processamento de RNA/genética , Fatores de Processamento de RNA/metabolismo , Prognóstico
9.
Viruses ; 16(5)2024 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-38793659

RESUMO

Respiratory syncytial virus (RSV) is the most prevalent cause of acute lower respiratory infection in young children. Currently, the first RSV vaccines are approved by the FDA. Recently, N6-methyladenosine (m6A) RNA methylation has been implicated in the regulation of the viral life cycle and replication of many viruses, including RSV. m6A methylation of RSV RNA has been demonstrated to promote replication and prevent anti-viral immune responses by the host. Whether m6A is also involved in viral entry and whether m6A can also affect RSV infection via different mechanisms than methylation of viral RNA is poorly understood. Here, we identify m6A reader YTH domain-containing protein 1 (YTHDC1) as a novel negative regulator of RSV infection. We demonstrate that YTHDC1 abrogates RSV infection by reducing the expression of RSV entry receptor CX3C motif chemokine receptor 1 (CX3CR1) on the cell surface of lung epithelial cells. Altogether, these data reveal a novel role for m6A methylation and YTHDC1 in the viral entry of RSV. These findings may contribute to the development of novel treatment options to control RSV infection.


Assuntos
Adenosina , Receptor 1 de Quimiocina CX3C , Infecções por Vírus Respiratório Sincicial , Vírus Sincicial Respiratório Humano , Internalização do Vírus , Humanos , Infecções por Vírus Respiratório Sincicial/virologia , Infecções por Vírus Respiratório Sincicial/metabolismo , Vírus Sincicial Respiratório Humano/genética , Vírus Sincicial Respiratório Humano/fisiologia , Adenosina/análogos & derivados , Adenosina/metabolismo , Receptor 1 de Quimiocina CX3C/metabolismo , Receptor 1 de Quimiocina CX3C/genética , Replicação Viral , Metilação , Regulação para Baixo , Fatores de Processamento de RNA/metabolismo , Fatores de Processamento de RNA/genética , Células Epiteliais/virologia , Células Epiteliais/metabolismo , Linhagem Celular , Células A549 , RNA Viral/genética , RNA Viral/metabolismo , Interações Hospedeiro-Patógeno , Proteínas do Tecido Nervoso
10.
RNA Biol ; 21(1): 1-17, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38711165

RESUMO

Spliceosome assembly contributes an important but incompletely understood aspect of splicing regulation. Prp45 is a yeast splicing factor which runs as an extended fold through the spliceosome, and which may be important for bringing its components together. We performed a whole genome analysis of the genetic interaction network of the truncated allele of PRP45 (prp45(1-169)) using synthetic genetic array technology and found chromatin remodellers and modifiers as an enriched category. In agreement with related studies, H2A.Z-encoding HTZ1, and the components of SWR1, INO80, and SAGA complexes represented prominent interactors, with htz1 conferring the strongest growth defect. Because the truncation of Prp45 disproportionately affected low copy number transcripts of intron-containing genes, we prepared strains carrying intronless versions of SRB2, VPS75, or HRB1, the most affected cases with transcription-related function. Intron removal from SRB2, but not from the other genes, partly repaired some but not all the growth phenotypes identified in the genetic screen. The interaction of prp45(1-169) and htz1Δ was detectable even in cells with SRB2 intron deleted (srb2Δi). The less truncated variant, prp45(1-330), had a synthetic growth defect with htz1Δ at 16°C, which also persisted in the srb2Δi background. Moreover, htz1Δ enhanced prp45(1-330) dependent pre-mRNA hyper-accumulation of both high and low efficiency splicers, genes ECM33 and COF1, respectively. We conclude that while the expression defects of low expression intron-containing genes contribute to the genetic interactome of prp45(1-169), the genetic interactions between prp45 and htz1 alleles demonstrate the sensitivity of spliceosome assembly, delayed in prp45(1-169), to the chromatin environment.


Assuntos
Íntrons , Fenótipo , Splicing de RNA , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Spliceossomos , Spliceossomos/metabolismo , Spliceossomos/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Regulação Fúngica da Expressão Gênica , Fatores de Processamento de RNA/genética , Fatores de Processamento de RNA/metabolismo , Histonas/metabolismo , Histonas/genética
11.
Sci Adv ; 10(19): eadn1547, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38718117

RESUMO

Pre-mRNA splicing is a fundamental step in gene expression, conserved across eukaryotes, in which the spliceosome recognizes motifs at the 3' and 5' splice sites (SSs), excises introns, and ligates exons. SS recognition and pairing is often influenced by protein splicing factors (SFs) that bind to splicing regulatory elements (SREs). Here, we describe SMsplice, a fully interpretable model of pre-mRNA splicing that combines models of core SS motifs, SREs, and exonic and intronic length preferences. We learn models that predict SS locations with 83 to 86% accuracy in fish, insects, and plants and about 70% in mammals. Learned SRE motifs include both known SF binding motifs and unfamiliar motifs, and both motif classes are supported by genetic analyses. Our comparisons across species highlight similarities between non-mammals, increased reliance on intronic SREs in plant splicing, and a greater reliance on SREs in mammalian splicing.


Assuntos
Éxons , Íntrons , Precursores de RNA , Sítios de Splice de RNA , Splicing de RNA , Precursores de RNA/genética , Precursores de RNA/metabolismo , Animais , Íntrons/genética , Éxons/genética , Genes de Plantas , Modelos Genéticos , Spliceossomos/metabolismo , Spliceossomos/genética , Plantas/genética , Humanos , Fatores de Processamento de RNA/genética , Fatores de Processamento de RNA/metabolismo
12.
Nat Commun ; 15(1): 3888, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38719828

RESUMO

PRPF40A plays an important role in the regulation of pre-mRNA splicing by mediating protein-protein interactions in the early steps of spliceosome assembly. By binding to proteins at the 5´ and 3´ splice sites, PRPF40A promotes spliceosome assembly by bridging the recognition of the splices. The PRPF40A WW domains are expected to recognize proline-rich sequences in SF1 and SF3A1 in the early spliceosome complexes E and A, respectively. Here, we combine NMR, SAXS and ITC to determine the structure of the PRPF40A tandem WW domains in solution and characterize the binding specificity and mechanism for proline-rich motifs recognition. Our structure of the PRPF40A WW tandem in complex with a high-affinity SF1 peptide reveals contributions of both WW domains, which also enables tryptophan sandwiching by two proline residues in the ligand. Unexpectedly, a proline-rich motif in the N-terminal region of PRPF40A mediates intramolecular interactions with the WW tandem. Using NMR, ITC, mutational analysis in vitro, and immunoprecipitation experiments in cells, we show that the intramolecular interaction acts as an autoinhibitory filter for proof-reading of high-affinity proline-rich motifs in bona fide PRPF40A binding partners. We propose that similar autoinhibitory mechanisms are present in most WW tandem-containing proteins to enhance binding selectivity and regulation of WW/proline-rich peptide interaction networks.


Assuntos
Prolina , Ligação Proteica , Domínios WW , Humanos , Motivos de Aminoácidos , Modelos Moleculares , Prolina/metabolismo , Prolina/química , Splicing de RNA , Fatores de Processamento de RNA/metabolismo , Fatores de Processamento de RNA/química , Fatores de Processamento de RNA/genética , Espalhamento a Baixo Ângulo , Spliceossomos/metabolismo , Difração de Raios X
14.
Mol Med ; 30(1): 62, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38760666

RESUMO

Alternative splicing (AS) is a strictly regulated process that generates multiple mRNA variants from a single gene, thus contributing to proteome diversity. Transcriptome-wide sequencing studies revealed networks of functionally coordinated splicing events, which produce isoforms with distinct or even opposing functions. To date, several mechanisms of AS are deregulated in leukemic cells, mainly due to mutations in splicing and/or epigenetic regulators and altered expression of splicing factors (SFs). In this review, we discuss aberrant splicing events induced by mutations affecting SFs (SF3B1, U2AF1, SRSR2, and ZRSR2), spliceosome components (PRPF8, LUC7L2, DDX41, and HNRNPH1), and epigenetic modulators (IDH1 and IDH2). Finally, we provide an extensive overview of the biological relevance of aberrant isoforms of genes involved in the regulation of apoptosis (e. g. BCL-X, MCL-1, FAS, and c-FLIP), activation of key cellular signaling pathways (CASP8, MAP3K7, and NOTCH2), and cell metabolism (PKM).


Assuntos
Processamento Alternativo , Neoplasias Hematológicas , Humanos , Neoplasias Hematológicas/genética , Fatores de Processamento de RNA/genética , Fatores de Processamento de RNA/metabolismo , Mutação , Animais , Regulação Neoplásica da Expressão Gênica , Epigênese Genética , Spliceossomos/metabolismo , Spliceossomos/genética , Transdução de Sinais/genética
15.
J Exp Clin Cancer Res ; 43(1): 141, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38745192

RESUMO

BACKGROUND: Neuroblastoma (NB) patients with amplified MYCN often face a grim prognosis and are resistant to existing therapies, yet MYCN protein is considered undruggable. KAP1 (also named TRIM28) plays a crucial role in multiple biological activities. This study aimed to investigate the relationship between KAP1 and MYCN in NB. METHODS: Transcriptome analyses and luciferase reporter assay identified that KAP1 was a downstream target of MYCN. The effects of KAP1 on cancer cell proliferation and colony formation were explored using the loss-of-function assays in vitro and in vivo. RNA stability detection was used to examine the influence of KAP1 on MYCN expression. The mechanisms of KAP1 to maintain MYCN mRNA stabilization were mainly investigated by mass spectrum, immunoprecipitation, RIP-qPCR, and western blotting. In addition, a xenograft mouse model was used to reveal the antitumor effect of STM2457 on NB. RESULTS: Here we identified KAP1 as a critical regulator of MYCN mRNA stability by protecting the RNA N6-methyladenosine (m6A) reader YTHDC1 protein degradation. KAP1 was highly expressed in clinical MYCN-amplified NB and was upregulated by MYCN. Reciprocally, KAP1 knockdown reduced MYCN mRNA stability and inhibited MYCN-amplified NB progression. Mechanistically, KAP1 regulated the stability of MYCN mRNA in an m6A-dependent manner. KAP1 formed a complex with YTHDC1 and RNA m6A writer METTL3 to regulate m6A-modified MYCN mRNA stability. KAP1 depletion decreased YTHDC1 protein stability and promoted MYCN mRNA degradation. Inhibiting MYCN mRNA m6A modification synergized with chemotherapy to restrain tumor progression in MYCN-amplified NB. CONCLUSIONS: Our research demonstrates that KAP1, transcriptionally activated by MYCN, forms a complex with YTHDC1 and METTL3, which in turn maintain the stabilization of MYCN mRNA in an m6A-dependent manner. Targeting m6A modification by STM2457, a small-molecule inhibitor of METTL3, could downregulate MYCN expression and attenuate tumor proliferation. This finding provides a new alternative putative therapeutic strategy for MYCN-amplified NB.


Assuntos
Proteína Proto-Oncogênica N-Myc , Neuroblastoma , Proteína 28 com Motivo Tripartido , Humanos , Neuroblastoma/genética , Neuroblastoma/metabolismo , Neuroblastoma/patologia , Camundongos , Animais , Proteína Proto-Oncogênica N-Myc/genética , Proteína Proto-Oncogênica N-Myc/metabolismo , Proteína 28 com Motivo Tripartido/metabolismo , Proteína 28 com Motivo Tripartido/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Estabilidade de RNA , Linhagem Celular Tumoral , Fatores de Processamento de RNA/metabolismo , Fatores de Processamento de RNA/genética , Proliferação de Células , Feminino , Regulação Neoplásica da Expressão Gênica , Camundongos Nus , Adenosina/análogos & derivados , Adenosina/metabolismo
16.
Nat Commun ; 15(1): 4110, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38750024

RESUMO

Maturation of eukaryotic pre-mRNAs via splicing and polyadenylation is modulated across cell types and conditions by a variety of RNA-binding proteins (RBPs). Although there exist over 1,500 RBPs in human cells, their binding motifs and functions still remain to be elucidated, especially in the complex environment of tissues and in the context of diseases. To overcome the lack of methods for the systematic and automated detection of sequence motif-guided pre-mRNA processing regulation from RNA sequencing (RNA-Seq) data we have developed MAPP (Motif Activity on Pre-mRNA Processing). Applying MAPP to RBP knock-down experiments reveals that many RBPs regulate both splicing and polyadenylation of nascent transcripts by acting on similar sequence motifs. MAPP not only infers these sequence motifs, but also unravels the position-dependent impact of the RBPs on pre-mRNA processing. Interestingly, all investigated RBPs that act on both splicing and 3' end processing exhibit a consistently repressive or activating effect on both processes, providing a first glimpse on the underlying mechanism. Applying MAPP to normal and malignant brain tissue samples unveils that the motifs bound by the PTBP1 and RBFOX RBPs coordinately drive the oncogenic splicing program active in glioblastomas demonstrating that MAPP paves the way for characterizing pre-mRNA processing regulators under physiological and pathological conditions.


Assuntos
Poliadenilação , Precursores de RNA , Splicing de RNA , Proteínas de Ligação a RNA , Humanos , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Precursores de RNA/metabolismo , Precursores de RNA/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias/genética , Neoplasias/metabolismo , Motivos de Nucleotídeos , Proteína de Ligação a Regiões Ricas em Polipirimidinas/metabolismo , Proteína de Ligação a Regiões Ricas em Polipirimidinas/genética , Fatores de Processamento de RNA/metabolismo , Fatores de Processamento de RNA/genética , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Ribonucleoproteínas Nucleares Heterogêneas/genética , RNA Mensageiro/metabolismo , RNA Mensageiro/genética
18.
Mol Syst Biol ; 20(6): 676-701, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38664594

RESUMO

Splice-switching oligonucleotides (SSOs) are antisense compounds that act directly on pre-mRNA to modulate alternative splicing (AS). This study demonstrates the value that artificial intelligence/machine learning (AI/ML) provides for the identification of functional, verifiable, and therapeutic SSOs. We trained XGboost tree models using splicing factor (SF) pre-mRNA binding profiles and spliceosome assembly information to identify modulatory SSO binding sites on pre-mRNA. Using Shapley and out-of-bag analyses we also predicted the identity of specific SFs whose binding to pre-mRNA is blocked by SSOs. This step adds considerable transparency to AI/ML-driven drug discovery and informs biological insights useful in further validation steps. We applied this approach to previously established functional SSOs to retrospectively identify the SFs likely to regulate those events. We then took a prospective validation approach using a novel target in triple negative breast cancer (TNBC), NEDD4L exon 13 (NEDD4Le13). Targeting NEDD4Le13 with an AI/ML-designed SSO decreased the proliferative and migratory behavior of TNBC cells via downregulation of the TGFß pathway. Overall, this study illustrates the ability of AI/ML to extract actionable insights from RNA-seq data.


Assuntos
Processamento Alternativo , Inteligência Artificial , Aprendizado de Máquina , Neoplasias de Mama Triplo Negativas , Humanos , Neoplasias de Mama Triplo Negativas/genética , Linhagem Celular Tumoral , Ubiquitina-Proteína Ligases Nedd4/genética , Ubiquitina-Proteína Ligases Nedd4/metabolismo , Precursores de RNA/genética , Precursores de RNA/metabolismo , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Fatores de Processamento de RNA/genética , Fatores de Processamento de RNA/metabolismo , Oligonucleotídeos Antissenso/genética , Movimento Celular/genética , Spliceossomos/metabolismo , Spliceossomos/genética , Oligonucleotídeos/genética , Feminino
19.
Free Radic Res ; 58(4): 261-275, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38599240

RESUMO

Iron is essential for all the lives and mitochondria integrate iron into heme and Fe-S clusters for diverse use as cofactors. Here, we screened mitochondrial proteins in KU812 human chronic myelogenous leukemia cells by glutathione S-transferase pulldown assay with PCBP2 to identify mitochondrial receptors for PCBP2, a major cytosolic Fe(II) chaperone. LC-MS analyses identified TOM20, sideroflexin-3 (SFXN3), SFXN1 and TOM70 in the affinity-score sequence. Stimulated emission depletion microscopy and proteinase-K digestion of mitochondria in HeLa cells revealed that TOM20 is located in the outer membrane of mitochondria whereas SFXN3 is located in the inner membrane. Although direct association was not observed between PCBP2 and SFXN3 with co-immunoprecipitation, proximity ligation assay demonstrated proximal localization of PCBP2 with TOM20 and there was a direct binding between TOM20 and SFXN3. Single knockdown either of PCBP2 and SFXN3 in K562 leukemia cells significantly decreased mitochondrial catalytic Fe(II) and mitochondrial maximal respiration. SFXN3 but not MFRN1 knockout (KO) in mouse embryonic fibroblasts decreased FBXL5 and heme oxygenase-1 (HO-1) but increased transferrin uptake and induced ferritin, indicating that mitochondrial iron entry through SFXN3 is distinct. MFRN1 KO revealed more intense mitochondrial Fe(II) deficiency than SFXN3 KO. Insufficient mitochondrial heme synthesis was evident under iron overload both with SFXN3 and MFRN KO, which was partially reversed by HO-1 inhibitor. Conversely, SFXN3 overexpression caused cytosolic iron deficiency with mitochondrial excess Fe(II), which further sensitized HeLa cells to RSL3-induced ferroptosis. In conclusion, we discovered a novel pathway of iron entry into mitochondria from cytosol through PCBP2-TOM20-SFXN3 axis.


Assuntos
Ferro , Mitocôndrias , Proteínas de Ligação a RNA , Humanos , Mitocôndrias/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Ferro/metabolismo , Animais , Receptores de Superfície Celular/metabolismo , Camundongos , Proteínas do Complexo de Importação de Proteína Precursora Mitocondrial/metabolismo , Células HeLa , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/genética , Fatores de Processamento de RNA/metabolismo , Fatores de Processamento de RNA/genética
20.
Cancer Sci ; 115(6): 1881-1895, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38566554

RESUMO

Triple-negative breast cancer (TNBC) exhibits heightened aggressiveness compared with other breast cancer (BC) subtypes, with earlier relapse, a higher risk of distant metastasis, and a worse prognosis. Transcription factors play a pivotal role in various cancers. Here, we found that factor forkhead box M1 (FOXM1) expression was significantly higher in TNBC than in other BC subtypes and normal tissues. Combining the findings of Gene Ontology (GO) enrichment analysis and a series of experiments, we found that knockdown of the FOXM1 gene attenuated the ability of TNBC cells to proliferate and metastasize both in vivo and in vitro. In addition, Spearman's test showed that FOXM1 significantly correlated with glycolysis-related genes, especially centromere protein A (CENPA) in datasets (GSE76250, GSE76124, GSE206912, and GSE103091). The effect of silencing FOXM1 on the inhibition of CENPA expression, TNBC proliferation, migration, and glycolysis could be recovered by overexpression of CENPA. According to MeRIP, the level of m6A modification on FOMX1 decreased in cells treated with cycloleucine (a m6A inhibitor) compared with that in the control group. The increase in FOXM1 expression caused by YTHDC1 overexpression could be reversed by the m6A inhibitor, which indicated that YTHDC1 enhanced FOXM1 expression depending on m6A modification. Therefore, we concluded that the YTHDC1-m6A modification/FOXM1/CENPA axis plays an important role in TNBC progression and glycolysis.


Assuntos
Proliferação de Células , Progressão da Doença , Proteína Forkhead Box M1 , Regulação Neoplásica da Expressão Gênica , Glicólise , Neoplasias de Mama Triplo Negativas , Humanos , Proteína Forkhead Box M1/metabolismo , Proteína Forkhead Box M1/genética , Neoplasias de Mama Triplo Negativas/patologia , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/metabolismo , Feminino , Glicólise/genética , Linhagem Celular Tumoral , Camundongos , Animais , Fatores de Processamento de RNA/metabolismo , Fatores de Processamento de RNA/genética , Movimento Celular/genética , Proteínas Cromossômicas não Histona/metabolismo , Proteínas Cromossômicas não Histona/genética , Adenosina/análogos & derivados , Adenosina/metabolismo , Camundongos Nus
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