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1.
Nat Commun ; 11(1): 4455, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32901005

RESUMO

Dysregulated alternative splicing (AS) driving carcinogenetic mitosis remains poorly understood. Here, we demonstrate that cancer metastasis-associated antigen 1 (MTA1), a well-known oncogenic chromatin modifier, broadly interacts and co-expresses with RBPs across cancers, contributing to cancerous mitosis-related AS. Using developed fCLIP-seq technology, we show that MTA1 binds abundant transcripts, preferentially at splicing-responsible motifs, influencing the abundance and AS pattern of target transcripts. MTA1 regulates the mRNA level and guides the AS of a series of mitosis regulators. MTA1 deletion abrogated the dynamic AS switches of variants for ATRX and MYBL2 at mitotic stage, which are relevant to mitosis-related tumorigenesis. MTA1 dysfunction causes defective mitotic arrest, leads to aberrant chromosome segregation, and results in chromosomal instability (CIN), eventually contributing to tumorigenesis. Currently, little is known about the RNA splicing during mitosis; here, we uncover that MTA1 binds transcripts and orchestrates dynamic splicing of mitosis regulators in tumorigenesis.


Assuntos
Carcinogênese/genética , Carcinogênese/metabolismo , Montagem e Desmontagem da Cromatina/fisiologia , Mitose/fisiologia , RNA Mensageiro/metabolismo , Proteínas Repressoras/metabolismo , Transativadores/metabolismo , Processamento Alternativo , Animais , Sítios de Ligação/genética , Montagem e Desmontagem da Cromatina/genética , Instabilidade Cromossômica , Feminino , Células HCT116 , Xenoenxertos , Humanos , Camundongos , Camundongos Nus , Mitose/genética , Neoplasias/genética , Neoplasias/metabolismo , Precursores de RNA/genética , Precursores de RNA/metabolismo , Processamento Pós-Transcricional do RNA , RNA Mensageiro/genética , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas Repressoras/antagonistas & inibidores , Proteínas Repressoras/genética , Transativadores/antagonistas & inibidores , Transativadores/genética
2.
Proc Natl Acad Sci U S A ; 117(28): 16516-16526, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32601179

RESUMO

LIN28B is highly expressed in neuroblastoma and promotes tumorigenesis, at least, in part, through inhibition of let-7 microRNA biogenesis. Here, we report that overexpression of either wild-type (WT) LIN28B or a LIN28B mutant that is unable to inhibit let-7 processing increases the penetrance of MYCN-induced neuroblastoma, potentiates the invasion and migration of transformed sympathetic neuroblasts, and drives distant metastases in vivo. Genome-wide chromatin immunoprecipitation coupled with massively parallel DNA sequencing (ChIP-seq) and coimmunoprecipitation experiments show that LIN28B binds active gene promoters in neuroblastoma cells through protein-protein interaction with the sequence-specific zinc-finger transcription factor ZNF143 and activates the expression of downstream targets, including transcription factors forming the adrenergic core regulatory circuitry that controls the malignant cell state in neuroblastoma as well as GSK3B and L1CAM that are involved in neuronal cell adhesion and migration. These findings reveal an unexpected let-7-independent function of LIN28B in transcriptional regulation during neuroblastoma pathogenesis.


Assuntos
Proteína Proto-Oncogênica N-Myc/metabolismo , Neuroblastoma/metabolismo , Proteínas de Ligação a RNA/metabolismo , Transativadores/metabolismo , Animais , Animais Geneticamente Modificados , Movimento Celular , Regulação Neoplásica da Expressão Gênica , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Proteína Proto-Oncogênica N-Myc/genética , Neuroblastoma/genética , Neuroblastoma/fisiopatologia , Ligação Proteica , Proteínas de Ligação a RNA/genética , Transativadores/genética , Peixe-Zebra
3.
Nat Commun ; 11(1): 3354, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620797

RESUMO

Expansion of an intronic (GGGGCC)n repeat region within the C9orf72 gene is a main cause of familial amyotrophic lateral sclerosis and frontotemporal dementia (c9ALS/FTD). A hallmark of c9ALS/FTD is the accumulation of misprocessed RNAs, which are often targets of cellular RNA surveillance. Here, we show that RNA decay mechanisms involving upstream frameshift 1 (UPF1), including nonsense-mediated decay (NMD), are inhibited in c9ALS/FTD brains and in cultured cells expressing either of two arginine-rich dipeptide repeats (R-DPRs), poly(GR) and poly(PR). Mechanistically, although R-DPRs cause the recruitment of UPF1 to stress granules, stress granule formation is independent of NMD inhibition. Instead, NMD inhibition is primarily a result from global translational repression caused by R-DPRs. Overexpression of UPF1, but none of its NMD-deficient mutants, enhanced the survival of neurons treated by R-DPRs, suggesting that R-DPRs cause neurotoxicity in part by inhibiting cellular RNA surveillance.


Assuntos
Esclerose Amiotrófica Lateral/genética , Proteína C9orf72/genética , Demência Frontotemporal/genética , Degradação do RNAm Mediada por Códon sem Sentido , RNA Helicases/metabolismo , Transativadores/metabolismo , Esclerose Amiotrófica Lateral/patologia , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Expansão das Repetições de DNA , Conjuntos de Dados como Assunto , Embrião de Mamíferos , Feminino , Lobo Frontal/patologia , Demência Frontotemporal/patologia , Humanos , Íntrons/genética , Camundongos , Neurônios/metabolismo , Neurônios/patologia , Cultura Primária de Células , Biossíntese de Proteínas , RNA Mensageiro/metabolismo , RNA-Seq , Transativadores/genética
4.
Nat Commun ; 11(1): 3345, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620802

RESUMO

Nonsense-mediated mRNA decay (NMD) is an evolutionarily conserved RNA decay mechanism that has emerged as a potent cell-intrinsic restriction mechanism of retroviruses and positive-strand RNA viruses. However, whether NMD is capable of restricting DNA viruses is not known. The DNA virus Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of Kaposi's sarcoma and primary effusion lymphoma (PEL). Here, we demonstrate that NMD restricts KSHV lytic reactivation. Leveraging high-throughput transcriptomics we identify NMD targets transcriptome-wide in PEL cells and identify host and viral RNAs as substrates. Moreover, we identified an NMD-regulated link between activation of the unfolded protein response and transcriptional activation of the main KSHV transcription factor RTA, itself an NMD target. Collectively, our study describes an intricate relationship between cellular targets of an RNA quality control pathway and KSHV lytic gene expression, and demonstrates that NMD can function as a cell intrinsic restriction mechanism acting upon DNA viruses.


Assuntos
Regulação Viral da Expressão Gênica , Herpesvirus Humano 8/genética , Degradação do RNAm Mediada por Códon sem Sentido , RNA Viral/metabolismo , Ativação Viral/genética , Linhagem Celular Tumoral , Células HEK293 , Herpesvirus Humano 8/metabolismo , Herpesvirus Humano 8/patogenicidade , Interações Hospedeiro-Patógeno/genética , Humanos , Proteínas Imediatamente Precoces/genética , Proteínas Imediatamente Precoces/metabolismo , Linfoma de Efusão Primária/genética , Linfoma de Efusão Primária/virologia , RNA Mensageiro/metabolismo , RNA-Seq , Sarcoma de Kaposi/genética , Sarcoma de Kaposi/virologia , Transativadores/genética , Transativadores/metabolismo , Ativação Transcricional , Resposta a Proteínas não Dobradas/genética , Latência Viral/genética
5.
J Clin Pathol ; 73(9): 527-530, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32699115

RESUMO

The GLIS 1-3 genes belong to a family of transcription factors, the Krüppel-like zinc finger proteins. The GLIS proteins function primarily as activators of transcription (GLIS 1 and 3), while GLIS 2 functions as a repressor. Collectively, the GLIS proteins are involved in a variety of diseases in several organs ranging from Alzheimer's disease, facial dysmorphism, neonatal diabetes mellitus, breast and colon cancers and leukaemia. In particular, loss-of-function mutations in GLIS2 are responsible for an autosomal recessive cystic kidney disease called nephronophthisis, which is characterised by tubular atrophy, interstitial fibrosis and corticomedullary cysts.Of diagnostic value in current practice are the presence of GLIS 3 and 1 fusions with PAX8 in almost 100% of hyalinising trabecular tumours of the thyroid gland. This enables its separation from papillary thyroid cancer.


Assuntos
Proteínas de Ligação a DNA/genética , Fatores de Transcrição Kruppel-Like/genética , Proteínas Repressoras/genética , Câncer Papilífero da Tireoide/genética , Neoplasias da Glândula Tireoide/genética , Transativadores/genética , Fatores de Transcrição/genética , Proteínas de Ligação a DNA/metabolismo , Fusão Gênica , Humanos , Fatores de Transcrição Kruppel-Like/metabolismo , Mutação com Perda de Função , Fator de Transcrição PAX8/genética , Fator de Transcrição PAX8/metabolismo , Proteínas Repressoras/metabolismo , Glândula Tireoide/patologia , Transativadores/metabolismo , Fatores de Transcrição/metabolismo
6.
Nat Commun ; 11(1): 3420, 2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32647127

RESUMO

Remyelination of the peripheral and central nervous systems (PNS and CNS, respectively) is a prerequisite for functional recovery after lesion. However, this process is not always optimal and becomes inefficient in the course of multiple sclerosis. Here we show that, when acetylated, eukaryotic elongation factor 1A1 (eEF1A1) negatively regulates PNS and CNS remyelination. Acetylated eEF1A1 (Ac-eEF1A1) translocates into the nucleus of myelinating cells where it binds to Sox10, a key transcription factor for PNS and CNS myelination and remyelination, to drag Sox10 out of the nucleus. We show that the lysine acetyltransferase Tip60 acetylates eEF1A1, whereas the histone deacetylase HDAC2 deacetylates eEF1A1. Promoting eEF1A1 deacetylation maintains the activation of Sox10 target genes and increases PNS and CNS remyelination efficiency. Taken together, these data identify a major mechanism of Sox10 regulation, which appears promising for future translational studies on PNS and CNS remyelination.


Assuntos
Fator 1 de Elongação de Peptídeos/metabolismo , Remielinização/genética , Ativação Transcricional/genética , Acetilação , Envelhecimento/metabolismo , Animais , Desdiferenciação Celular/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Histona Desacetilase 1/metabolismo , Histona Desacetilase 2/metabolismo , Lisina Acetiltransferase 5/metabolismo , Camundongos , Modelos Biológicos , Oligodendroglia/efeitos dos fármacos , Oligodendroglia/metabolismo , Sistema Nervoso Periférico/efeitos dos fármacos , Sistema Nervoso Periférico/fisiologia , Recuperação de Função Fisiológica/efeitos dos fármacos , Remielinização/efeitos dos fármacos , Fatores de Transcrição SOXE/metabolismo , Fator de Transcrição STAT3/metabolismo , Células de Schwann/efeitos dos fármacos , Células de Schwann/metabolismo , Teofilina/farmacologia , Transativadores/metabolismo , Ativação Transcricional/efeitos dos fármacos
7.
Gene ; 757: 144938, 2020 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-32640305

RESUMO

Myb-like SWIRM and MPN domains (MYSM1) is a chromatin-binding transcriptional regulator that mediates histone 2A deubiquitination, which plays a vital role in hematopoiesis and lymphocyte differentiation. Biallelic variants in MYSM1 cause a rare bone marrow failure syndrome (OMIM #618116). To date, only three pathogenic variants (E390*, R478*, and H656R) of MYSM1 have been reported in nine patients, and all variants are homozygous. Here, we describe a Chinese female patient who mainly presented with leukopenia, granulocytopenia, thrombocytopenia, severe anemia, and B-cell and natural killer cell deficiency in the peripheral blood, and was diagnosed with bone marrow failure. Trio whole-exome sequencing revealed a novel compound heterozygous variant in MYSM1 (c.399G > A, p.L133L, and c.1467C > G, p.Y489*). The c.399G > A synonymous variant is located at the 3'-end of exon 6, which is predicted to affect MYSM1 mRNA splicing. Analysis of the products obtained from the reverse transcription-polymerase chain reaction revealed that the c.399G > A variant leads to exon 6 skipping, resulting in a premature termination codon (c.321_399 del, p.V108Lfs*13). cDNA sequencing suggested that the c.1467C > G variant triggered nonsense-mediated mRNA degradation. Moreover, we identified a novel transcript of MYSM1 mRNA (missing exons 5 and 6) in human blood cells. Our results expand the mutation spectrum of MYSM1; additionally, this is the first report of a synonymous splicing variant that induces post-transcriptional skipping of exon 6 leading to a bone marrow failure syndrome phenotype.


Assuntos
Síndrome Congênita de Insuficiência da Medula Óssea/genética , Mutação , Transativadores/genética , Proteases Específicas de Ubiquitina/genética , Síndrome Congênita de Insuficiência da Medula Óssea/patologia , Feminino , Células HEK293 , Heterozigoto , Humanos , Lactente , Processamento de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transativadores/metabolismo , Proteases Específicas de Ubiquitina/metabolismo
8.
PLoS Biol ; 18(7): e3000561, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32702011

RESUMO

Maternal ß-catenin activity is essential and critical for dorsal induction and its dorsal activation has been thoroughly studied. However, how the maternal ß-catenin activity is suppressed in the nondorsal cells remains poorly understood. Nanog is known to play a central role for maintenance of the pluripotency and maternal -zygotic transition (MZT). Here, we reveal a novel role of Nanog as a strong repressor of maternal ß-catenin signaling to safeguard the embryo against hyperactivation of maternal ß-catenin activity and hyperdorsalization. In zebrafish, knockdown of nanog at different levels led to either posteriorization or dorsalization, mimicking zygotic or maternal activation of Wnt/ß-catenin activities, and the maternal zygotic mutant of nanog (MZnanog) showed strong activation of maternal ß-catenin activity and hyperdorsalization. Although a constitutive activator-type Nanog (Vp16-Nanog, lacking the N terminal) perfectly rescued the MZT defects of MZnanog, it did not rescue the phenotypes resulting from ß-catenin signaling activation. Mechanistically, the N terminal of Nanog directly interacts with T-cell factor (TCF) and interferes with the binding of ß-catenin to TCF, thereby attenuating the transcriptional activity of ß-catenin. Therefore, our study establishes a novel role for Nanog in repressing maternal ß-catenin activity and demonstrates a transcriptional switch between ß-catenin/TCF and Nanog/TCF complexes, which safeguards the embryo from global activation of maternal ß-catenin activity.


Assuntos
Desenvolvimento Embrionário/genética , Proteína Homeobox Nanog/metabolismo , Transativadores/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/genética , beta Catenina/metabolismo , Animais , Padronização Corporal/genética , Núcleo Celular/metabolismo , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Técnicas de Silenciamento de Genes , Masculino , Mutação/genética , Proteína Homeobox Nanog/química , Proteína Homeobox Nanog/genética , Ligação Proteica , Transporte Proteico , Proteínas Repressoras/metabolismo , Transcrição Genética , Via de Sinalização Wnt/genética , Proteínas de Peixe-Zebra/química , Proteínas de Peixe-Zebra/genética , Zigoto/metabolismo
9.
PLoS One ; 15(7): e0236101, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32678829

RESUMO

Dysregulation of histone demethylase Jumonji-C domain-containing protein 5 (JMJD5) has been identified as a great effect on tumorigenesis. Silibinin is a commonly used anti-hepatotoxic drug and exhibits anticancer effect in various cancers. However, the antitumor mechanism between silibinin and JMJD5 in oral squamous cell carcinoma (OSCC) remains unclear. In this study, the clinical significance of JMJD5 on OSCC patients was assessed through tissue microarray. Furthermore, mice bearing patient-derived tumor xenografts (PDTXs) and tongue cancer cell lines were treated with silibinin and evaluated for tumor growth and JMJD5 expression. High expression of JMJD5 in oral cancer was significantly associated with tumor size (P = 0.0241), cervical node metastasis (P = 0.0001) and clinical stage (P = 0.0002), was associated with worse survival rate compared with that of the total cohort (P = 0.0002). Collectively the data indicate that JMJD5 expression may be suitable for detection of unfavorable prognosis in OSCC patients, based in part on its apparent role as a marker of metastasis. In addition, silibinin inhibits cancer growth in vitro and in PDTX models. Furthermore, metastasis-associated protein 1 (MTA1) could regulate the expression for JMJD5 and had a positive correlation with JMJD5. Moreover, silibinin could downregulate JMJD5 and MTA1 in oral cancer. Present study thus identifies that JMJD5 might be an essential prognostic indicator and therapeutic target against OSCC progression. In addition, silibinin is a potential candidate among novel chemotherapeutic agents or adjuvants for modulating JMJD5 in OSCC, through a mechanism likely involving MTA1/JMJD5 axis.


Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma de Células Escamosas/patologia , Proliferação de Células , Histona Desmetilases/metabolismo , Neoplasias Bucais/patologia , Proteínas Repressoras/metabolismo , Silibina/farmacologia , Transativadores/metabolismo , Animais , Antineoplásicos Fitogênicos/farmacologia , Apoptose , Biomarcadores Tumorais/genética , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/metabolismo , Feminino , Regulação Neoplásica da Expressão Gênica , Histona Desmetilases/genética , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Neoplasias Bucais/tratamento farmacológico , Neoplasias Bucais/metabolismo , Prognóstico , Proteínas Repressoras/genética , Taxa de Sobrevida , Transativadores/genética , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
10.
Mol Cell Biol ; 40(18)2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32631903

RESUMO

Precursor B cell acute lymphoblastic leukemia (B-ALL) is caused by genetic lesions in developing B cells that function as drivers for the accumulation of additional mutations in an evolutionary selection process. We investigated secondary drivers of leukemogenesis in a mouse model of B-ALL driven by PU.1/Spi-B deletion (Mb1-CreΔPB). Whole-exome-sequencing analysis revealed recurrent mutations in Jak3 (encoding Janus kinase 3), Jak1, and Ikzf3 (encoding Aiolos). Mutations with a high variant-allele frequency (VAF) were dominated by C→T transition mutations that were compatible with activation-induced cytidine deaminase, whereas the majority of mutations, with a low VAF, were dominated by C→A transversions associated with 8-oxoguanine DNA damage caused by reactive oxygen species (ROS). The Janus kinase (JAK) inhibitor ruxolitinib delayed leukemia onset, reduced ROS and ROS-induced gene expression signatures, and altered ROS-induced mutational signatures. These results reveal that JAK mutations can alter the course of leukemia clonal evolution through ROS-induced DNA damage.


Assuntos
Dano ao DNA , Janus Quinase 1/genética , Janus Quinase 1/metabolismo , Leucemia de Células B/metabolismo , Animais , Linfócitos B/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Humanos , Janus Quinase 3/metabolismo , Leucemia de Células B/genética , Leucemia de Células B/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutação , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-ets/genética , Proteínas Proto-Oncogênicas c-ets/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transativadores/genética , Transativadores/metabolismo
11.
Nature ; 584(7820): 268-273, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32728211

RESUMO

The ability of the skin to grow in response to stretching has been exploited in reconstructive surgery1. Although the response of epidermal cells to stretching has been studied in vitro2,3, it remains unclear how mechanical forces affect their behaviour in vivo. Here we develop a mouse model in which the consequences of stretching on skin epidermis can be studied at single-cell resolution. Using a multidisciplinary approach that combines clonal analysis with quantitative modelling and single-cell RNA sequencing, we show that stretching induces skin expansion by creating a transient bias in the renewal activity of epidermal stem cells, while a second subpopulation of basal progenitors remains committed to differentiation. Transcriptional and chromatin profiling identifies how cell states and gene-regulatory networks are modulated by stretching. Using pharmacological inhibitors and mouse mutants, we define the step-by-step mechanisms that control stretch-mediated tissue expansion at single-cell resolution in vivo.


Assuntos
Mecanotransdução Celular/fisiologia , Análise de Célula Única , Pele/citologia , Pele/crescimento & desenvolvimento , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Junções Aderentes/metabolismo , Animais , Sequência de Bases , Proteínas de Ciclo Celular/metabolismo , Diferenciação Celular/efeitos dos fármacos , Autorrenovação Celular/efeitos dos fármacos , Cromatina/efeitos dos fármacos , Cromatina/genética , Montagem e Desmontagem da Cromatina/efeitos dos fármacos , Células Clonais/citologia , Células Clonais/efeitos dos fármacos , Células Clonais/metabolismo , Modelos Animais de Doenças , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Redes Reguladoras de Genes/efeitos dos fármacos , Hidrogéis/administração & dosagem , Hidrogéis/farmacologia , Mecanotransdução Celular/efeitos dos fármacos , Mecanotransdução Celular/genética , Camundongos , Camundongos Transgênicos , Quinases de Proteína Quinase Ativadas por Mitógeno/antagonistas & inibidores , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Mutação , RNA Mensageiro/genética , RNA-Seq , Pele/efeitos dos fármacos , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo , Transativadores/antagonistas & inibidores , Transativadores/metabolismo , Fator de Transcrição AP-1/metabolismo , Transcrição Genética/efeitos dos fármacos
12.
Water Res ; 183: 116092, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32622230

RESUMO

Microcystins (MCs) are the most common cyanotoxins produced by harmful cyanobacterial blooms and pose an increasing global threat to human health and ecosystems. Microbial degradation represents an efficient and sustainable approach for the removal of MCs. Although the enzymatic pathway for biodegradation of MCs has been characterized, the regulatory mechanisms underlying the degradation processes remain unclear. Quorum sensing (QS) is a cell-density-dependent regulatory mechanism that enables bacteria to orchestrate collective behaviors. The acyl-homoserine lactone (AHL)-mediated QS system regulates the biodegradation of many organic pollutants. However, it is not known whether this QS system is involved in the degradation of MCs. This study aimed to fill this knowledge gap. In this study, the proportion of culturable AHL-producers increased significantly after enrichment of MCs, and AHL-based QS systems were present in all genome-sequenced MC-degrading strains, supporting the hypothesis that QS participates in the degradation of MCs. Two bifunctional Novosphingobium strains (with MC-degrading and AHL-producing abilities) were isolated using a novel primer pair targeting mlrA, the marker gene of mlr degradation pathway. Biochemical and genetic analysis revealed that the MC-degrading bacterium Novosphingobium sp. ERW19 encodes two hierarchical regulatory QS systems designated novR1/novI1 and novR2/novI2. Gene knockout and complementation experiments indicated that both systems were required for efficient degradation of MCs. Transcriptomic analyses revealed that the QS systems positively regulate degradation of MCs through transcriptional activation of MC-degrading genes, especially mlrA. Given that QS may be a common trait within mlr pathway-dependent MC-degrading bacterial strains and the degradation activity is directly regulated by QS, manipulation of the QS systems may be a promising strategy to control biodegradation of MCs.


Assuntos
Acil-Butirolactonas , Percepção de Quorum , Proteínas de Bactérias , Ecossistema , Microcistinas , Transativadores
13.
Anticancer Res ; 40(6): 3255-3264, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32487620

RESUMO

BACKGROUND/AIM: Rta, a transactivator of Epstein-Barr virus, is associated with progression of nasopharyngel carcinoma (NPC); however, its mechanism of contribution to the pathogenesis of NPC remains unclear. Interleukin-6 (IL-6), a tumor promoter, is detected in NPC. This in vitro study examined whether and how Rta promotes NPC progression by up-regulating IL-6. MATERIALS AND METHODS: Semiquantitative reverse transcription-polymerase chain reaction (RT-PCR), quantitative real-time PCR, ELISA, immunoblotting assays, reporter gene assays, and transwell migration assays were performed. RESULTS: In NPC cells, Rta up-regulated IL-6 expression at the mRNA and protein levels, and the Rta's C-terminus was essential for promoter activation and expression of IL-6. The induction of IL-6 by Rta also required activation of extracellular signal-regulated kinase 1/2 and activator protein-1. Furthermore, IL-6 secreted from Rta-expressing NPC cells promoted migration of Rta-negative NPC cells by activating IL-6 receptor/Janus kinase/signal transducer and activator of transcription 3 pathway. CONCLUSION: Rta contributes to progression of NPC cells through induction of IL-6 in vitro.


Assuntos
Proteínas Imediatamente Precoces/metabolismo , Interleucina-6/metabolismo , Janus Quinases/metabolismo , Neoplasias/metabolismo , Receptores de Interleucina-6/metabolismo , Fator de Transcrição STAT3/metabolismo , Transativadores/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Neoplasias da Mama/virologia , Linhagem Celular Tumoral , Movimento Celular/fisiologia , Humanos , Proteínas Imediatamente Precoces/genética , Interleucina-6/biossíntese , Interleucina-6/genética , Sistema de Sinalização das MAP Quinases , Células MCF-7 , Carcinoma Nasofaríngeo/genética , Carcinoma Nasofaríngeo/metabolismo , Carcinoma Nasofaríngeo/patologia , Carcinoma Nasofaríngeo/virologia , Neoplasias Nasofaríngeas/genética , Neoplasias Nasofaríngeas/metabolismo , Neoplasias Nasofaríngeas/patologia , Neoplasias Nasofaríngeas/virologia , Neoplasias/genética , Neoplasias/patologia , Neoplasias/virologia , Transdução de Sinais , Neoplasias Gástricas/genética , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Neoplasias Gástricas/virologia , Transativadores/genética , Fator de Transcrição AP-1/metabolismo , Transfecção , Regulação para Cima
14.
Proc Natl Acad Sci U S A ; 117(25): 14421-14432, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32522871

RESUMO

Epstein-Barr virus (EBV) is a B cell transforming virus that causes B cell malignancies under conditions of immune suppression. EBV orchestrates B cell transformation through its latent membrane proteins (LMPs) and Epstein-Barr nuclear antigens (EBNAs). We here identify secondary mutations in mouse B cell lymphomas induced by LMP1, to predict and identify key functions of other EBV genes during transformation. We find aberrant activation of early B cell factor 1 (EBF1) to promote transformation of LMP1-expressing B cells by inhibiting their differentiation to plasma cells. EBV EBNA3A phenocopies EBF1 activities in LMP1-expressing B cells, promoting transformation while inhibiting differentiation. In cells expressing LMP1 together with LMP2A, EBNA3A only promotes lymphomagenesis when the EBNA2 target Myc is also overexpressed. Collectively, our data support a model where proproliferative activities of LMP1, LMP2A, and EBNA2 in combination with EBNA3A-mediated inhibition of terminal plasma cell differentiation critically control EBV-mediated B cell lymphomagenesis.


Assuntos
Transformação Celular Viral , Infecções por Vírus Epstein-Barr/patologia , Herpesvirus Humano 4/patogenicidade , Linfoma de Células B/patologia , Plasmócitos/patologia , Animais , Diferenciação Celular , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/genética , Modelos Animais de Doenças , Infecções por Vírus Epstein-Barr/virologia , Antígenos Nucleares do Vírus Epstein-Barr/metabolismo , Fibroblastos , Herpesvirus Humano 4/metabolismo , Humanos , Linfoma de Células B/virologia , Camundongos , Camundongos Knockout , Plasmócitos/virologia , Cultura Primária de Células , Transativadores/genética , Transativadores/metabolismo , Proteínas da Matriz Viral/metabolismo , Proteínas Virais/metabolismo
15.
Nat Commun ; 11(1): 3106, 2020 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-32561765

RESUMO

Nonsense-mediated mRNA decay (NMD) typifies an mRNA surveillance pathway. Because NMD necessitates a translation event to recognize a premature termination codon on mRNAs, truncated misfolded polypeptides (NMD-polypeptides) could potentially be generated from NMD substrates as byproducts. Here, we show that when the ubiquitin-proteasome system is overwhelmed, various misfolded polypeptides including NMD-polypeptides accumulate in the aggresome: a perinuclear nonmembranous compartment eventually cleared by autophagy. Hyperphosphorylation of the key NMD factor UPF1 is required for selective targeting of the misfolded polypeptide aggregates toward the aggresome via the CTIF-eEF1A1-DCTN1 complex: the aggresome-targeting cellular machinery. Visualization at a single-particle level reveals that UPF1 increases the frequency and fidelity of movement of CTIF aggregates toward the aggresome. Furthermore, the apoptosis induced by proteotoxic stresses is suppressed by UPF1 hyperphosphorylation. Altogether, our data provide evidence that UPF1 functions in the regulation of a protein surveillance as well as an mRNA quality control.


Assuntos
Degradação do RNAm Mediada por Códon sem Sentido , Complexo de Endopeptidases do Proteassoma/metabolismo , RNA Helicases/metabolismo , RNA Mensageiro/metabolismo , Transativadores/metabolismo , Resposta a Proteínas não Dobradas/genética , Autofagia , Códon sem Sentido , Complexo Dinactina/metabolismo , Fatores de Iniciação em Eucariotos/metabolismo , Células HEK293 , Células HeLa , Humanos , Imagem Molecular , Fator 1 de Elongação de Peptídeos/metabolismo , Fosforilação , Agregados Proteicos/genética , Imagem Individual de Molécula , Ubiquitina/metabolismo
16.
Ecotoxicol Environ Saf ; 201: 110802, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32531573

RESUMO

Extended exposure to inorganic arsenic through contaminated drinking water has been linked with increased incidence of diabetes mellitus. The most common exposure occurs through the consumption of contaminated drinking water mainly through geogenic sources of inorganic arsenic. Epigenetic modifications are important mechanisms through which environmental pollutants could exert their toxic effects. Bisulfite sequencing polymerase chain reaction method followed by Sanger sequencing was performed for DNA methylation analysis. Our results showed that sodium arsenite treatment significantly reduced insulin secretion in pancreatic islets. It was revealed that the methylation of glucose transporter 2 (Glut2) gene was changed at two cytosine-phosphate-guanine (CpG) sites (-1743, -1734) in the promoter region of the sodium arsenite-treated group comparing to the control. No changes were observed in the methylation status of peroxisome proliferator-activated receptor-gamma (PPARγ), pancreatic and duodenal homeobox 1 (Pdx1) and insulin 2 (Ins2) CpG sites in the targeted regions. Measuring the gene expression level showed increase in Glut2 expression, while the expression of insulin (INS) and Pdx1 were significantly affected by sodium arsenite treatment. This study revealed that exposure to sodium arsenite changed the DNA methylation pattern of Glut2, a key transporter of glucose entry into the pancreatic beta cells (ß-cells). Our data suggested possible epigenetic-mediated toxicity mechanism for arsenite-induced ß-cells dysfunction. Further studies are needed to dissect the precise epigenetic modulatory activity of sodium arsenite that affect the biogenesis of insulin.


Assuntos
Arsenitos/toxicidade , Metilação de DNA/efeitos dos fármacos , Transportador de Glucose Tipo 2/genética , Insulina/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Compostos de Sódio/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Epigênese Genética/efeitos dos fármacos , Proteínas de Homeodomínio/genética , Técnicas In Vitro , Insulina/genética , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Masculino , Regiões Promotoras Genéticas , Ratos , Ratos Wistar , Transativadores/genética
17.
Nat Commun ; 11(1): 2728, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32483114

RESUMO

The Pseudomonas putida phenol-responsive regulator DmpR is a bacterial enhancer binding protein (bEBP) from the AAA+ ATPase family. Even though it was discovered more than two decades ago and has been widely used for aromatic hydrocarbon sensing, the activation mechanism of DmpR has remained elusive. Here, we show that phenol-bound DmpR forms a tetramer composed of two head-to-head dimers in a head-to-tail arrangement. The DmpR-phenol complex exhibits altered conformations within the C-termini of the sensory domains and shows an asymmetric orientation and angle in its coiled-coil linkers. The structural changes within the phenol binding sites and the downstream ATPase domains suggest that the effector binding signal is propagated through the coiled-coil helixes. The tetrameric DmpR-phenol complex interacts with the σ54 subunit of RNA polymerase in presence of an ATP analogue, indicating that DmpR-like bEBPs tetramers utilize a mechanistic mode distinct from that of hexameric AAA+ ATPases to activate σ54-dependent transcription.


Assuntos
Adenosina Trifosfatases/química , Proteínas de Bactérias/química , Proteínas de Ligação a DNA/química , Conformação Proteica , Multimerização Proteica , Transativadores/química , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sítios de Ligação/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , RNA Polimerases Dirigidas por DNA/metabolismo , Regulação Bacteriana da Expressão Gênica , Fenol/metabolismo , Ligação Proteica , Pseudomonas putida/enzimologia , Pseudomonas putida/genética , Homologia de Sequência de Aminoácidos , Transativadores/genética , Transativadores/metabolismo
18.
Nature ; 583(7815): 310-313, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32494006

RESUMO

The U2 small nuclear ribonucleoprotein (snRNP) has an essential role in the selection of the precursor mRNA branch-site adenosine, the nucleophile for the first step of splicing1. Stable addition of U2 during early spliceosome formation requires the DEAD-box ATPase PRP52-7. Yeast U2 small nuclear RNA (snRNA) nucleotides that form base pairs with the branch site are initially sequestered in a branchpoint-interacting stem-loop (BSL)8, but whether the human U2 snRNA folds in a similar manner is unknown. The U2 SF3B1 protein, a common mutational target in haematopoietic cancers9, contains a HEAT domain (SF3B1HEAT) with an open conformation in isolated SF3b10, but a closed conformation in spliceosomes11, which is required for stable interaction between U2 and the branch site. Here we report a 3D cryo-electron microscopy structure of the human 17S U2 snRNP at a core resolution of 4.1 Å and combine it with protein crosslinking data to determine the molecular architecture of this snRNP. Our structure reveals that SF3B1HEAT interacts with PRP5 and TAT-SF1, and maintains its open conformation in U2 snRNP, and that U2 snRNA forms a BSL that is sandwiched between PRP5, TAT-SF1 and SF3B1HEAT. Thus, substantial remodelling of the BSL and displacement of BSL-interacting proteins must occur to allow formation of the U2-branch-site helix. Our studies provide a structural explanation of why TAT-SF1 must be displaced before the stable addition of U2 to the spliceosome, and identify RNP rearrangements facilitated by PRP5 that are required for stable interaction between U2 and the branch site.


Assuntos
Microscopia Crioeletrônica , Ribonucleoproteína Nuclear Pequena U2/química , Ribonucleoproteína Nuclear Pequena U2/ultraestrutura , Sequência de Bases , RNA Helicases DEAD-box/química , RNA Helicases DEAD-box/metabolismo , Células HeLa , Humanos , Modelos Moleculares , Fosfoproteínas/química , Fosfoproteínas/metabolismo , Ligação Proteica , Conformação Proteica , Fatores de Processamento de RNA/química , Fatores de Processamento de RNA/metabolismo , Ribonucleoproteína Nuclear Pequena U2/genética , Ribonucleoproteína Nuclear Pequena U2/metabolismo , Transativadores/química , Transativadores/metabolismo
19.
Life Sci ; 256: 117969, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32553926

RESUMO

AIMS: Cannabinoids are the chemical compounds with a high affinity for cannabinoid receptors affecting the central nervous system through the release of neurotransmitters. However, the current knowledge related to the role of such compounds in the regulation of cellular aging is limited. This study aimed to investigate the effect of cannabidiol and tetrahydrocannabinol on the function of aged pancreatic islets. MAIN METHODS: The expression of p53, p38, p21, p16, and Glut2 genes and ß-galactosidase activity were measured as hallmarks of cell aging applying real-time PCR, ELISA, and immunocytochemistry techniques. Pdx1 protein expression, insulin release, and oxidative stress markers were compared between young and aged rat pancreatic islet cells. KEY FINDINGS: Upon the treatment of aged pancreatic islets cells with cannabidiol and tetrahydrocannabinol, the expression of p53, p38, p21 and the activity of ß-galactosidase were reduced. Cannabidiol and tetrahydrocannabinol increase insulin release, Pdx1, Glut2, and thiol molecules expression, while the oxidative stress parameters were decreased. The enhanced expression of Pdx1 and insulin release in aged pancreatic islet cells reflects the extension of cell healthy aging due to the significant reduction of ROS. SIGNIFICANCE: This study provides evidence for the involvement of cannabidiol and tetrahydrocannabinol in the oxidation process of cellular aging.


Assuntos
Canabinoides/farmacologia , Senescência Celular , Ilhotas Pancreáticas/citologia , Espécies Reativas de Oxigênio/metabolismo , Animais , Biomarcadores/metabolismo , Canabidiol/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Senescência Celular/efeitos dos fármacos , Dronabinol/farmacologia , Proteínas de Homeodomínio/metabolismo , Secreção de Insulina/efeitos dos fármacos , Masculino , Estresse Oxidativo/efeitos dos fármacos , Ratos Wistar , Transativadores/metabolismo
20.
PLoS Genet ; 16(6): e1008869, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32569302

RESUMO

We investigate mutations in trß2, a splice variant of thrb, identifying changes in function, structure, and behavior in larval and adult zebrafish retinas. Two N-terminus CRISPR mutants were identified. The first is a 6BP+1 insertion deletion frameshift resulting in a truncated protein. The second is a 3BP in frame deletion with intact binding domains. ERG recordings of isolated cone signals showed that the 6BP+1 mutants did not respond to red wavelengths of light while the 3BP mutants did respond. 6BP+1 mutants lacked optomotor and optokinetic responses to red/black and green/black contrasts. Both larval and adult 6BP+1 mutants exhibit a loss of red-cone contribution to the ERG and an increase in UV-cone contribution. Transgenic reporters show loss of cone trß2 activation in the 6BP+1 mutant but increase in the density of cones with active blue, green, and UV opsin genes. Antibody reactivity for red-cone LWS1 and LWS2 opsin was absent in the 6BP+1 mutant, as was reactivity for arrestin3a. Our results confirm a critical role for trß2 in long-wavelength cone development.


Assuntos
Visão de Cores/genética , Regulação da Expressão Gênica no Desenvolvimento , Genes erbA/genética , Retina/crescimento & desenvolvimento , Receptores beta dos Hormônios Tireóideos/genética , Animais , Animais Geneticamente Modificados , Diferenciação Celular/genética , Opsinas dos Cones/genética , Opsinas dos Cones/metabolismo , Mutação da Fase de Leitura , Mutação INDEL , Larva , Modelos Animais , Células Fotorreceptoras de Invertebrados/patologia , Retina/citologia , Retina/patologia , Deleção de Sequência , Transativadores/genética , Transativadores/metabolismo , Peixe-Zebra/genética , Peixe-Zebra/crescimento & desenvolvimento , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
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