RESUMEN
mRNA biogenesis in the eukaryotic nucleus is a highly complex process. The numerous RNA processing steps are tightly coordinated to ensure that only fully processed transcripts are released from chromatin for export from the nucleus. Here, we present the hypothesis that fission yeast Dbp2, a ribonucleoprotein complex (RNP) remodelling ATPase of the DEAD-box family, is the key enzyme in an RNP assembly checkpoint at the 3'-end of genes. We show that Dbp2 interacts with the cleavage and polyadenylation complex (CPAC) and localises to cleavage bodies, which are enriched for 3'-end processing factors and proteins involved in nuclear RNA surveillance. Upon loss of Dbp2, 3'-processed, polyadenylated RNAs accumulate on chromatin and in cleavage bodies, and CPAC components are depleted from the soluble pool. Under these conditions, cells display an increased likelihood to skip polyadenylation sites and a delayed transcription termination, suggesting that levels of free CPAC components are insufficient to maintain normal levels of 3'-end processing. Our data support a model in which Dbp2 is the active component of an mRNP remodelling checkpoint that licenses RNA export and is coupled to CPAC release.
Asunto(s)
ARN Helicasas DEAD-box , Ribonucleoproteínas , Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Ribonucleoproteínas/metabolismo , Ribonucleoproteínas/genética , ARN Helicasas DEAD-box/metabolismo , ARN Helicasas DEAD-box/genética , Proteínas de Schizosaccharomyces pombe/metabolismo , Proteínas de Schizosaccharomyces pombe/genética , Poliadenilación , ARN Mensajero/metabolismo , ARN Mensajero/genética , Factores de Escisión y Poliadenilación de ARNm/metabolismo , Factores de Escisión y Poliadenilación de ARNm/genética , Cromatina/metabolismo , ARN de Hongos/metabolismo , ARN de Hongos/genética , Núcleo Celular/metabolismoRESUMEN
The interconnections between co-transcriptional regulation, chromatin environment, and transcriptional output remain poorly understood. Here, we investigate the mechanism underlying RNA 3' processing-mediated Polycomb silencing of Arabidopsis FLOWERING LOCUS C (FLC). We show a requirement for ANTHESIS PROMOTING FACTOR 1 (APRF1), a homolog of yeast Swd2 and human WDR82, known to regulate RNA polymerase II (RNA Pol II) during transcription termination. APRF1 interacts with TYPE ONE SERINE/THREONINE PROTEIN PHOSPHATASE 4 (TOPP4) (yeast Glc7/human PP1) and LUMINIDEPENDENS (LD), the latter showing structural features found in Ref2/PNUTS, all components of the yeast and human phosphatase module of the CPF 3' end-processing machinery. LD has been shown to co-associate in vivo with the histone H3 K4 demethylase FLOWERING LOCUS D (FLD). This work shows how the APRF1/LD-mediated polyadenylation/termination process influences subsequent rounds of transcription by changing the local chromatin environment at FLC.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Cromatina , Regulación de la Expresión Génica de las Plantas , Silenciador del Gen , Proteínas de Dominio MADS , ARN Polimerasa II , Terminación de la Transcripción Genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/enzimología , Cromatina/metabolismo , Cromatina/genética , Proteínas de Dominio MADS/genética , Proteínas de Dominio MADS/metabolismo , ARN Polimerasa II/metabolismo , ARN Polimerasa II/genética , Fosfoproteínas Fosfatasas/genética , Fosfoproteínas Fosfatasas/metabolismo , Factores de Escisión y Poliadenilación de ARNm/metabolismo , Factores de Escisión y Poliadenilación de ARNm/genética , Histonas/metabolismo , Histonas/genética , Histona DesacetilasasRESUMEN
Regulation of codon optimality is an increasingly appreciated layer of cell- and tissue-specific protein expression control. Here, we use codon-modified reporters to show that differentiation of Drosophila neural stem cells into neurons enables protein expression from rare-codon-enriched genes. From a candidate screen, we identify the cytoplasmic polyadenylation element binding (CPEB) protein Orb2 as a positive regulator of rare-codon-dependent mRNA stability in neurons. Using RNA sequencing, we reveal that Orb2-upregulated mRNAs in the brain with abundant Orb2 binding sites have a rare-codon bias. From these Orb2-regulated mRNAs, we demonstrate that rare-codon enrichment is important for mRNA stability and social behavior function of the metabotropic glutamate receptor (mGluR). Our findings reveal a molecular mechanism by which neural stem cell differentiation shifts genetic code regulation to enable critical mRNA stability and protein expression.
Asunto(s)
Diferenciación Celular , Proteínas de Drosophila , Células-Madre Neurales , Neuronas , Estabilidad del ARN , ARN Mensajero , Animales , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Neuronas/metabolismo , Neuronas/citología , ARN Mensajero/metabolismo , ARN Mensajero/genética , Diferenciación Celular/genética , Células-Madre Neurales/metabolismo , Células-Madre Neurales/citología , Codón/genética , Drosophila melanogaster/genética , Drosophila melanogaster/citología , Drosophila melanogaster/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Receptores de Glutamato Metabotrópico/genética , Factores de Escisión y Poliadenilación de ARNm/metabolismo , Factores de Escisión y Poliadenilación de ARNm/genética , Drosophila/genética , Drosophila/metabolismo , Encéfalo/metabolismo , Encéfalo/citología , Factores de TranscripciónRESUMEN
Pancreatic cancer is the deadliest malignancy with a poor response to chemotherapy but is potentially indicated for ferroptosis therapy. Here we identified that cytoplasmic polyadenylation element binding protein 1 (CPEB1) regulates NRF2 proteostasis and susceptibility to ferroptosis in pancreatic ductal adenocarcinoma (PDAC). We found that CPEB1 deficiency in cancer cells promotes the translation of p62/SQSTM1 by facilitating mRNA polyadenylation. Consequently, upregulated p62 enhances NRF2 stability by sequestering KEAP1, an E3 ligase for proteasomal degradation of NRF2, leading to the transcriptional activation of anti-ferroptosis genes. In support of the critical role of this signaling cascade in cancer therapy, CPEB1-deficient pancreatic cancer cells display higher resistance to ferroptosis-inducing agents than their CPEB1-normal counterparts in vitro and in vivo. Furthermore, based on the pathological evaluation of tissue specimens from 90 PDAC patients, we established that CPEB1 is an independent prognosticator whose expression level is closely associated with clinical therapeutic outcomes in PDAC. These findings identify the role of CPEB1 as a key ferroptosis regulator and a potential prognosticator in pancreatic cancer.
Asunto(s)
Ferroptosis , Factor 2 Relacionado con NF-E2 , Neoplasias Pancreáticas , Humanos , Ferroptosis/genética , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patología , Factor 2 Relacionado con NF-E2/metabolismo , Factor 2 Relacionado con NF-E2/genética , Línea Celular Tumoral , Animales , Factores de Escisión y Poliadenilación de ARNm/metabolismo , Factores de Escisión y Poliadenilación de ARNm/genética , Ratones , Proteostasis , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patología , Carcinoma Ductal Pancreático/genética , Proteína 1 Asociada A ECH Tipo Kelch/metabolismo , Proteína 1 Asociada A ECH Tipo Kelch/genética , Ratones DesnudosRESUMEN
Mitophagy is a specific type of autophagy responsible for the selective elimination of dysfunctional or superfluous mitochondria, ensuring the maintenance of mitochondrial quality control. The initiation of mitophagy is coordinated by the ULK1 kinase complex, which engages mitophagy receptors via its FIP200 subunit. Whether FIP200 performs additional functions in the subsequent later phases of mitophagy beyond this initial step and how its regulation occurs, remains unclear. Our findings reveal that multiple phosphorylation events on FIP200 differentially control the early and late stages of mitophagy. Furthermore, these phosphorylation events influence FIP200's interaction with ATG16L1. In summary, our results highlight the necessity for precise and dynamic regulation of FIP200, underscoring its importance in the progression of mitophagy.
Asunto(s)
Proteínas Relacionadas con la Autofagia , Mitocondrias , Mitofagia , Fosforilación , Proteínas Relacionadas con la Autofagia/metabolismo , Proteínas Relacionadas con la Autofagia/genética , Humanos , Mitocondrias/metabolismo , Homólogo de la Proteína 1 Relacionada con la Autofagia/metabolismo , Homólogo de la Proteína 1 Relacionada con la Autofagia/genética , Factores de Escisión y Poliadenilación de ARNm/metabolismo , Factores de Escisión y Poliadenilación de ARNm/genética , Células HeLa , Proteínas Portadoras/metabolismoRESUMEN
The RNA-binding protein cytoplasmic polyadenylation element binding 1 (CPEB1) plays a fundamental role in regulating mRNA translation in oocytes. However, the specifics of how and which protein kinase cascades modulate CPEB1 activity are still controversial. Using genetic and pharmacological tools, and detailed time courses, we have re-evaluated the relationship between CPEB1 phosphorylation and translation activation during mouse oocyte maturation. We show that both the CDK1/MAPK and AURKA/PLK1 pathways converge on CPEB1 phosphorylation during prometaphase of meiosis I. Only inactivation of the CDK1/MAPK pathway disrupts translation, whereas inactivation of either pathway alone leads to CPEB1 stabilization. However, CPEB1 stabilization induced by inactivation of the AURKA/PLK1 pathway does not affect translation, indicating that destabilization and/or degradation is not linked to translational activation. The accumulation of endogenous CCNB1 protein closely recapitulates the translation data that use an exogenous template. These findings support the overarching hypothesis that the activation of translation during prometaphase in mouse oocytes relies on a CDK1/MAPK-dependent CPEB1 phosphorylation, and that translational activation precedes CPEB1 destabilization.
Asunto(s)
Meiosis , Oocitos , Biosíntesis de Proteínas , Factores de Transcripción , Factores de Escisión y Poliadenilación de ARNm , Animales , Femenino , Ratones , Aurora Quinasa A/metabolismo , Aurora Quinasa A/genética , Proteína Quinasa CDC2/metabolismo , Proteína Quinasa CDC2/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Ciclina B1/metabolismo , Ciclina B1/genética , Factores de Escisión y Poliadenilación de ARNm/metabolismo , Factores de Escisión y Poliadenilación de ARNm/genética , Oocitos/metabolismo , Oocitos/citología , Fosforilación , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas/genética , Transducción de Señal , Factores de Transcripción/metabolismo , Factores de Transcripción/genéticaRESUMEN
The HIV-1 capsid (CA) protein forms the outer shell of the viral core that is released into the cytoplasm upon infection. CA binds various cellular proteins, including CPSF6, that direct HIV-1 integration into speckle-associated domains in host chromatin. Upon HIV-1 infection, CPSF6 forms puncta in the nucleus. Here, we characterised these CPSF6 puncta further in HeLa cells, T-cells and macrophages and confirmed that integration and reverse transcription are not required for puncta formation. Indeed, we found that puncta formed very rapidly after infection, correlating with the time that CA entered the nucleus. In aphidicolin-treated HeLa cells and macrophages, puncta were detected for the length of the experiment, suggesting that puncta are only lost upon cell division. CA still co-localised with CPSF6 puncta at the latest time points, considerably after the peak of reverse transcription and integration. Intriguingly, the number of puncta induced in macrophages did not correlate with the MOI or the total number of nuclear speckles present in each cell, suggesting that CA/CPSF6 is only directed to a few nuclear speckles. Furthermore, we found that CPSF6 already co-localised with nuclear speckles in uninfected T-cells, suggesting that HIV-1 promotes a natural behaviour of CPSF6.
Asunto(s)
VIH-1 , Macrófagos , Linfocitos T , Factores de Escisión y Poliadenilación de ARNm , VIH-1/fisiología , Humanos , Factores de Escisión y Poliadenilación de ARNm/metabolismo , Factores de Escisión y Poliadenilación de ARNm/genética , Linfocitos T/virología , Linfocitos T/metabolismo , Células HeLa , Macrófagos/virología , Macrófagos/metabolismo , Integración Viral , Núcleo Celular/metabolismo , Proteínas de la Cápside/metabolismo , Proteínas de la Cápside/genética , Infecciones por VIH/virología , Infecciones por VIH/metabolismo , Cápside/metabolismoRESUMEN
The initial stages of HIV-1 infection involve the transport of the viral core into the nuclear compartment. The presence of the HIV-1 core in the nucleus triggers the translocation of CPSF6/CPSF5 from paraspeckles into nuclear speckles, forming puncta-like structures. While this phenomenon is well-documented, the efficiency of CPSF6 translocation to nuclear speckles upon HIV-1 infection varies depending on the type of cell used. In some human cell lines, only 1-2% of the cells translocate CPSF6 to nuclear speckles when exposed to a 95% infection rate. To address the issue that only 1-2% of cells translocate CPSF6 to nuclear speckles when a 95% infection rate is achieved, we screened several human cell lines and identified a human a cell line in which approximately 85% of the cells translocate CPSF6 to nuclear speckles when 95% infection rate is achieved. This cellular system has enabled the development of a robust fluorescence microscopy method to quantify the translocation of CPSF6 into nuclear speckles following HIV-1 infection. This assay holds the potential to support studies aimed at understanding the role of CPSF6 translocation to nuclear speckles in HIV-1 infection. Additionally, since the translocation of CPSF6 into nuclear speckles depends on the physical presence of the viral core in the nucleus, our method also serves as a reporter of HIV-1 nuclear import.
Asunto(s)
Transporte Activo de Núcleo Celular , Núcleo Celular , VIH-1 , Factores de Escisión y Poliadenilación de ARNm , Humanos , Línea Celular , Núcleo Celular/metabolismo , Infecciones por VIH/virología , Infecciones por VIH/metabolismo , VIH-1/genética , VIH-1/metabolismo , Factores de Escisión y Poliadenilación de ARNm/metabolismo , Factores de Escisión y Poliadenilación de ARNm/genéticaRESUMEN
Inflammatory damage in ovarian granulosa cells (GCs) is a key mechanism in polycystic ovary syndrome (PCOS), cytoplasmic polyadenylation element binding protein-1 (CPEB1) is important in inflammatory regulation, however, its role in PCOS is unclear. We aim to research the mechanism of CPEB1 in ovarian GCs in PCOS using dehydroepiandrosterone (DHEA)-induced PCOS rat models and testosterone-incubated GC models. The pathophysiology in PCOS rats was analyzed. Quantitative-realtime-PCR, TUNEL, immunohistochemistry, and Western blot were applied for quantification. Additionally, cell counting kit-8, flow cytometry, immunofluorescence, Western blot, and Monodansylcadaverine staining were performed. We found that PCOS rat models exhibited a disrupted estrus cycle, elevated serum levels of testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH), increased LH/FSH ratio, and heightened ovarian index. Furthermore, reduced corpus luteum and increased follicular cysts were observed in ovarian tissue. In ovarian tissue, autophagy and apoptosis were activated and CPEB1 was overexpressed. In vitro, CPEB1 overexpression inhibited cell viability and sirtuin-1 (SIRT1), activated tumor necrosis factor-α, and interleukin-6 levels, as well as apoptosis and autophagy; however, CPEB1 knockdown had the opposite effect. In conclusion, overexpression of CPEB1 activated autophagy and apoptosis of ovarian GCs in PCOS.
Asunto(s)
Síndrome del Ovario Poliquístico , Animales , Femenino , Ratas , Apoptosis , Autofagia , Hormona Folículo Estimulante Humana , Células de la Granulosa , Hormona Luteinizante , Factores de Escisión y Poliadenilación de ARNm/genética , Síndrome del Ovario Poliquístico/inducido químicamente , Testosterona , Factores de TranscripciónAsunto(s)
Asma , Proteínas de Fusión Oncogénica , Receptor alfa de Factor de Crecimiento Derivado de Plaquetas , Factores de Escisión y Poliadenilación de ARNm , Humanos , Proteínas de Fusión Oncogénica/genética , Factores de Escisión y Poliadenilación de ARNm/genética , Asma/genética , Asma/patología , Asma/complicaciones , Receptor alfa de Factor de Crecimiento Derivado de Plaquetas/genética , Masculino , Eosinófilos/patología , Eosinófilos/metabolismo , Eosinofilia/patología , Eosinofilia/genética , Persona de Mediana Edad , FemeninoRESUMEN
Orb2 the Drosophila homolog of cytoplasmic polyadenylation element binding (CPEB) protein forms prion-like oligomers. These oligomers consist of Orb2A and Orb2B isoforms and their formation is dependent on the oligomerization of the Orb2A isoform. Drosophila with a mutation diminishing Orb2A's prion-like oligomerization forms long-term memory but fails to maintain it over time. Since this prion-like oligomerization of Orb2A plays a crucial role in the maintenance of memory, here, we aim to find what regulates this oligomerization. In an immunoprecipitation-based screen, we identify interactors of Orb2A in the Hsp40 and Hsp70 families of proteins. Among these, we find an Hsp40 family protein Mrj as a regulator of the conversion of Orb2A to its prion-like form. Mrj interacts with Hsp70 proteins and acts as a chaperone by interfering with the aggregation of pathogenic Huntingtin. Unlike its mammalian homolog, we find Drosophila Mrj is neither an essential gene nor causes any gross neurodevelopmental defect. We observe a loss of Mrj results in a reduction in Orb2 oligomers. Further, Mrj knockout exhibits a deficit in long-term memory and our observations suggest Mrj is needed in mushroom body neurons for the regulation of long-term memory. Our work implicates a chaperone Mrj in mechanisms of memory regulation through controlling the oligomerization of Orb2A and its association with the translating ribosomes.
Asunto(s)
Proteínas de Drosophila , Proteínas del Choque Térmico HSP40 , Memoria a Largo Plazo , Animales , Drosophila melanogaster/metabolismo , Drosophila melanogaster/genética , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas del Choque Térmico HSP40/metabolismo , Proteínas del Choque Térmico HSP40/genética , Proteínas HSP70 de Choque Térmico/metabolismo , Proteínas HSP70 de Choque Térmico/genética , Memoria a Largo Plazo/fisiología , Factores de Escisión y Poliadenilación de ARNm/metabolismo , Factores de Escisión y Poliadenilación de ARNm/genética , Cuerpos Pedunculados/metabolismo , Multimerización de Proteína , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismoRESUMEN
Messenger RNA precursors (pre-mRNA) generally undergo 3' end processing by cleavage and polyadenylation (CPA), which is specified by a polyadenylation site (PAS) and adjacent RNA sequences and regulated by a large variety of core and auxiliary CPA factors. To date, most of the human CPA factors have been discovered through biochemical and proteomic studies. However, genetic identification of the human CPA factors has been hampered by the lack of a reliable genome-wide screening method. We describe here a dual fluorescence readthrough reporter system with a PAS inserted between two fluorescent reporters. This system enables measurement of the efficiency of 3' end processing in living cells. Using this system in combination with a human genome-wide CRISPR/Cas9 library, we conducted a screen for CPA factors. The screens identified most components of the known core CPA complexes and other known CPA factors. The screens also identified CCNK/CDK12 as a potential core CPA factor, and RPRD1B as a CPA factor that binds RNA and regulates the release of RNA polymerase II at the 3' ends of genes. Thus, this dual fluorescence reporter coupled with CRISPR/Cas9 screens reliably identifies bona fide CPA factors and provides a platform for investigating the requirements for CPA in various contexts.
Asunto(s)
Sistemas CRISPR-Cas , Genes Reporteros , Precursores del ARN , Factores de Escisión y Poliadenilación de ARNm , Humanos , Quinasas Ciclina-Dependientes/metabolismo , Quinasas Ciclina-Dependientes/genética , Genoma Humano , Células HEK293 , Factores de Escisión y Poliadenilación de ARNm/metabolismo , Factores de Escisión y Poliadenilación de ARNm/genética , Poliadenilación , División del ARN , ARN Polimerasa II/metabolismo , Precursores del ARN/metabolismo , Precursores del ARN/genéticaRESUMEN
3' end processing of most eukaryotic precursor-mRNAs (pre-mRNAs) is a crucial cotranscriptional process that generally involves the cleavage and polyadenylation of the precursor transcripts. Within the human 3' end processing machinery, the four-subunit mammalian polyadenylation specificity factor (mPSF) recognizes the polyadenylation signal (PAS) in the pre-mRNA and recruits the poly(A) polymerase α (PAPOA) to it. To shed light on the molecular mechanisms of PAPOA recruitment to mPSF, we used a combination of cryogenic-electron microscopy (cryo-EM) single-particle analysis, computational structure prediction, and in vitro biochemistry to reveal an intricate interaction network. A short linear motif in the mPSF subunit FIP1 interacts with the structured core of human PAPOA, with a binding mode that is evolutionarily conserved from yeast to human. In higher eukaryotes, however, PAPOA contains a conserved C-terminal motif that can interact intramolecularly with the same residues of the PAPOA structured core used to bind FIP1. Interestingly, using biochemical assay and cryo-EM structural analysis, we found that the PAPOA C-terminal motif can also directly interact with mPSF at the subunit CPSF160. These results show that PAPOA recruitment to mPSF is mediated by two distinct intermolecular connections and further suggest the presence of mutually exclusive interactions in the regulation of 3' end processing.
Asunto(s)
Microscopía por Crioelectrón , Polinucleotido Adenililtransferasa , Factores de Escisión y Poliadenilación de ARNm , Humanos , Factores de Escisión y Poliadenilación de ARNm/metabolismo , Factores de Escisión y Poliadenilación de ARNm/química , Factores de Escisión y Poliadenilación de ARNm/genética , Polinucleotido Adenililtransferasa/metabolismo , Polinucleotido Adenililtransferasa/genética , Polinucleotido Adenililtransferasa/química , Unión Proteica , Poliadenilación , Modelos Moleculares , Precursores del ARN/metabolismo , Precursores del ARN/genética , Precursores del ARN/química , Factor de Especificidad de Desdoblamiento y Poliadenilación/metabolismo , Factor de Especificidad de Desdoblamiento y Poliadenilación/genética , Factor de Especificidad de Desdoblamiento y Poliadenilación/químicaRESUMEN
The human WDR33 gene encodes three major isoforms. The canonical isoform WDR33v1 (V1) is a well-characterized nuclear mRNA polyadenylation factor, while the other two, WDR33v2 (V2) and WDR33v3 (V3), have not been studied. Here, we report that V2 and V3 are generated by alternative polyadenylation, and neither protein contains all seven WD (tryptophan-aspartic acid) repeats that characterize V1. Surprisingly, V2 and V3 are not polyadenylation factors but localize to the endoplasmic reticulum and interact with stimulator of interferon genes (STING), the immune factor that induces the cellular response to cytosolic double-stranded DNA. V2 suppresses interferon-ß induction by preventing STING disulfide oligomerization but promotes autophagy, likely by recruiting WIPI2 isoforms. V3, on the other hand, functions to increase STING protein levels. Our study has not only provided mechanistic insights into STING regulation but also revealed that protein isoforms can be functionally completely unrelated, indicating that alternative mRNA processing is a more powerful mechanism than previously appreciated.
Asunto(s)
Poliadenilación , Factores de Escisión y Poliadenilación de ARNm , Humanos , Factores de Escisión y Poliadenilación de ARNm/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas de la Membrana/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Inmunidad InnataRESUMEN
Alternative polyadenylation (APA) is a widespread mechanism of gene regulation that generates mRNA isoforms with alternative 3' untranslated regions (3' UTRs). Our previous study has revealed the global 3' UTR shortening of host mRNAs through APA upon viral infection. However, how the dynamic changes in the APA landscape occur upon viral infection remains largely unknown. Here we further found that, the reduced protein abundance of CPSF6, one of the core 3' processing factors, promotes the usage of proximal poly(A) sites (pPASs) of many immune related genes in macrophages and fibroblasts upon viral infection. Shortening of the 3' UTR of these transcripts may improve their mRNA stability and translation efficiency, leading to the promotion of type I IFN (IFN-I) signalling-based antiviral immune responses. In addition, dysregulated expression of CPSF6 is also observed in many immune related physiological and pathological conditions, especially in various infections and cancers. Thus, the global APA dynamics of immune genes regulated by CPSF6, can fine-tune the antiviral response as well as the responses to other cellular stresses to maintain the tissue homeostasis, which may represent a novel regulatory mechanism for antiviral immunity.
Asunto(s)
Poliadenilación , Virosis , Factores de Escisión y Poliadenilación de ARNm , Humanos , Regiones no Traducidas 3'/genética , Regulación hacia Abajo , Inmunidad/genética , Factores de Escisión y Poliadenilación de ARNm/genética , Factores de Escisión y Poliadenilación de ARNm/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Virosis/genética , Ratones , AnimalesRESUMEN
Cleavage and polyadenylation specificity factor subunit 6 (CPSF6, also known as CFIm68) is a 68 kDa component of the mammalian cleavage factor I (CFIm) complex that modulates mRNA alternative polyadenylation (APA) and determines 3' untranslated region (UTR) length, an important gene expression control mechanism. CPSF6 directly interacts with the HIV-1 core during infection, suggesting involvement in HIV-1 replication. Here, we review the contributions of CPSF6 to every stage of the HIV-1 replication cycle. Recently, several groups described the ability of HIV-1 infection to induce CPSF6 translocation to nuclear speckles, which are biomolecular condensates. We discuss the implications for CPSF6 localization in condensates and the potential role of condensate-localized CPSF6 in the ability of HIV-1 to control the protein expression pattern of the cell.
Asunto(s)
VIH-1 , Replicación Viral , Factores de Escisión y Poliadenilación de ARNm , VIH-1/genética , VIH-1/fisiología , VIH-1/metabolismo , Factores de Escisión y Poliadenilación de ARNm/metabolismo , Factores de Escisión y Poliadenilación de ARNm/genética , Humanos , Condensados Biomoleculares/metabolismo , Infecciones por VIH/virología , Infecciones por VIH/metabolismo , Infecciones por VIH/genética , Transporte de Proteínas , Poliadenilación , Núcleo Celular/metabolismo , Regiones no Traducidas 3'/genéticaRESUMEN
The ribonucleic acid (RNA)-binding protein Cytoplasmic Polyadenylation Element Binding Protein 1 (CPEB1), a key member of the CPEB family, is essential in controlling gene expression involved in both healthy physiological and pathological processes. CPEB1 can bind to the 3'- untranslated regions (UTR) of substrate messenger ribonucleic acid (mRNA) and regulate its translation. There is increasing evidence that CPEB1 is closely related to the pathological basis of atherosclerosis. According to recent investigations, many pathological processes, including inflammation, lipid metabolism, endothelial dysfunction, angiogenesis, oxidative stress, cellular senescence, apoptosis, and insulin resistance, are regulated by CPEB1. This review considers the prevention and treatment of atherosclerotic heart disease in relation to the evolution of the physiological function of CPEB1, recent research breakthroughs, and the potential participation of CPEB1 in atherosclerosis.
Asunto(s)
Aterosclerosis , Factores de Escisión y Poliadenilación de ARNm , Humanos , Aterosclerosis/metabolismo , Aterosclerosis/genética , Aterosclerosis/patología , Animales , Factores de Escisión y Poliadenilación de ARNm/genética , Factores de Escisión y Poliadenilación de ARNm/metabolismo , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Regulación de la Expresión Génica , Transducción de SeñalRESUMEN
Oogenesis is a complex process regulated by precise coordination of multiple factors, including maternal genes. Zygote arrest 1 (zar1) has been identified as an ovary-specific maternal gene that is vital for oocyte-to-embryo transition and oogenesis in mouse and zebrafish. However, its function in other species remains to be elucidated. In the present study, zar1 was identified with conserved C-terminal zinc finger domains in Nile tilapia. zar1 was highly expressed in the ovary and specifically expressed in phase I and II oocytes. Disruption of zar1 led to the failed transition from oogonia to phase I oocytes, with somatic cell apoptosis. Down-regulation and failed polyadenylation of figla, gdf9, bmp15 and wee2 mRNAs were observed in the ovaries of zar1-/- fish. Cpeb1, a gene essential for polyadenylation that interacts with Zar1, was down-regulated in zar1-/- fish. Moreover, decreased levels of serum estrogen and increased levels of androgen were observed in zar1-/- fish. Taken together, zar1 seems to be essential for tilapia oogenesis by regulating polyadenylation and estrogen synthesis. Our study shows that Zar1 has different molecular functions during gonadal development by the similar signaling pathway in different species.
Asunto(s)
Proteínas del Huevo , Proteínas de Peces , Tilapia , Animales , Femenino , Ratones , Cíclidos/genética , Cíclidos/metabolismo , Proteínas del Huevo/metabolismo , Estrógenos , Factores de Escisión y Poliadenilación de ARNm/genética , Oogénesis/genética , Poliadenilación , Tilapia/genética , Tilapia/metabolismo , Factores de Transcripción/genética , Pez Cebra/metabolismo , Proteínas de Peces/metabolismoAsunto(s)
Eosinofilia , Síndrome Hipereosinofílico , Neoplasias , Humanos , Mesilato de Imatinib , Eosinofilia/genética , Eosinofilia/patología , Receptor alfa de Factor de Crecimiento Derivado de Plaquetas/genética , Proteínas de Fusión Oncogénica/genética , Factores de Escisión y Poliadenilación de ARNm/genéticaRESUMEN
The Pcf11 protein is an essential subunit of the large complex that cleaves and polyadenylates eukaryotic mRNA precursor. It has also been functionally linked to gene-looping, termination of RNA Polymerase II (Pol II) transcripts, and mRNA export. We have examined a poorly characterized but conserved domain (amino acids 142-225) of the Saccharomyces cerevisiae Pcf11 and found that while it is not needed for mRNA 3' end processing or termination downstream of the poly(A) sites of protein-coding genes, its presence improves the interaction with Pol II and the use of transcription terminators near gene promoters. Analysis of genome-wide Pol II occupancy in cells with Pcf11 missing this region, as well as Pcf11 mutated in the Pol II CTD Interacting Domain, indicates that systematic changes in mRNA expression are mediated primarily at the level of transcription. Global expression analysis also shows that a general stress response, involving both activation and suppression of specific gene sets known to be regulated in response to a wide variety of stresses, is induced in the two pcf11 mutants, even though cells are grown in optimal conditions. The mutants also cause an unbalanced expression of cell wall-related genes that does not activate the Cell Wall Integrity pathway but is associated with strong caffeine sensitivity. Based on these findings, we propose that Pcf11 can modulate the expression level of specific functional groups of genes in ways that do not involve its well-characterized role in mRNA 3' end processing.