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1.
Mol Cell ; 60(3): 475-86, 2015 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-26593721

RESUMO

The regulation of protein synthesis contributes to gene expression in both normal physiology and disease, yet kinetic investigations of the human translation mechanism are currently lacking. Using single-molecule fluorescence imaging methods, we have quantified the nature and timing of structural processes in human ribosomes during single-turnover and processive translation reactions. These measurements reveal that functional complexes exhibit dynamic behaviors and thermodynamic stabilities distinct from those observed for bacterial systems. Structurally defined sub-states of pre- and post-translocation complexes were sensitive to specific inhibitors of the eukaryotic ribosome, demonstrating the utility of this platform to probe drug mechanism. The application of three-color single-molecule fluorescence resonance energy transfer (smFRET) methods further revealed a long-distance allosteric coupling between distal tRNA binding sites within ribosomes bearing three tRNAs, which contributed to the rate of processive translation.


Assuntos
Biossíntese de Proteínas , RNA de Transferência/química , Ribossomos/química , Regulação Alostérica , Transferência Ressonante de Energia de Fluorescência , Humanos , RNA de Transferência/metabolismo , Ribossomos/metabolismo
2.
Development ; 145(5)2018 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-29437830

RESUMO

Human cleft lip with or without cleft palate (CL/P) is a common craniofacial abnormality caused by impaired fusion of the facial prominences. We have previously reported that, in the mouse embryo, epithelial apoptosis mediates fusion at the seam where the prominences coalesce. Here, we show that apoptosis alone is not sufficient to remove the epithelial layers. We observed morphological changes in the seam epithelia, intermingling of cells of epithelial descent into the mesenchyme and molecular signatures of epithelial-mesenchymal transition (EMT). Utilizing mouse lines with cephalic epithelium-specific Pbx loss exhibiting CL/P, we demonstrate that these cellular behaviors are Pbx dependent, as is the transcriptional regulation of the EMT driver Snail1. Furthermore, in the embryo, the majority of epithelial cells expressing high levels of Snail1 do not undergo apoptosis. Pbx1 loss- and gain-of-function in a tractable epithelial culture system revealed that Pbx1 is both necessary and sufficient for EMT induction. This study establishes that Pbx-dependent EMT programs mediate murine upper lip/primary palate morphogenesis and fusion via regulation of Snail1. Of note, the EMT signatures observed in the embryo are mirrored in the epithelial culture system.


Assuntos
Padronização Corporal/genética , Transição Epitelial-Mesenquimal/genética , Face/embriologia , Morfogênese/genética , Nariz/embriologia , Fator de Transcrição 1 de Leucemia de Células Pré-B/fisiologia , Fatores de Transcrição da Família Snail/genética , Animais , Apoptose/genética , Células Cultivadas , Fenda Labial/embriologia , Fenda Labial/genética , Fissura Palatina/embriologia , Fissura Palatina/genética , Embrião de Mamíferos , Face/anormalidades , Regulação da Expressão Gênica no Desenvolvimento , Lábio/embriologia , Camundongos , Camundongos Transgênicos , Palato/embriologia , Fator de Transcrição 1 de Leucemia de Células Pré-B/genética
3.
Int J Mol Sci ; 21(15)2020 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-32722591

RESUMO

Non-communicable diseases (NCDs) are medical conditions that, by definition, are non-infectious and non-transmissible among people. Much of current NCDs are generally due to genetic, behavioral, and metabolic risk factors that often include excessive alcohol consumption, smoking, obesity, and untreated elevated blood pressure, and share many common signal transduction pathways. Alterations in cell and physiological signaling and transcriptional control pathways have been well studied in several human NCDs, but these same pathways also regulate expression and function of the protein synthetic machinery and mRNA translation which have been less well investigated. Alterations in expression of specific translation factors, and disruption of canonical mRNA translational regulation, both contribute to the pathology of many NCDs. The two most common pathological alterations that contribute to NCDs discussed in this review will be the regulation of eukaryotic initiation factor 2 (eIF2) by the integrated stress response (ISR) and the mammalian target of rapamycin complex 1 (mTORC1) pathways. Both pathways integrally connect mRNA translation activity to external and internal physiological stimuli. Here, we review the role of ISR control of eIF2 activity and mTORC1 control of cap-mediated mRNA translation in some common NCDs, including Alzheimer's disease, Parkinson's disease, stroke, diabetes mellitus, liver cirrhosis, chronic obstructive pulmonary disease (COPD), and cardiac diseases. Our goal is to provide insights that further the understanding as to the important role of translational regulation in the pathogenesis of these diseases.


Assuntos
Fator de Iniciação 2 em Eucariotos/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Doenças não Transmissíveis , Biossíntese de Proteínas , Transdução de Sinais , Humanos , Fosforilação
4.
PLoS Genet ; 12(8): e1006217, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27500936

RESUMO

Ribosome biogenesis is essential for cell growth and proliferation and is commonly elevated in cancer. Accordingly, numerous oncogene and tumor suppressor signaling pathways target rRNA synthesis. In breast cancer, non-canonical Wnt signaling by Wnt5a has been reported to antagonize tumor growth. Here, we show that Wnt5a rapidly represses rDNA gene transcription in breast cancer cells and generates a chromatin state with reduced transcription of rDNA by RNA polymerase I (Pol I). These effects were specifically dependent on Dishevelled1 (DVL1), which accumulates in nucleolar organizer regions (NORs) and binds to rDNA regions of the chromosome. Upon DVL1 binding, the Pol I transcription activator and deacetylase Sirtuin 7 (SIRT7) releases from rDNA loci, concomitant with disassembly of Pol I transcription machinery at the rDNA promoter. These findings reveal that Wnt5a signals through DVL1 to suppress rRNA transcription. This provides a novel mechanism for how Wnt5a exerts tumor suppressive effects and why disruption of Wnt5a signaling enhances mammary tumor growth in vivo.


Assuntos
Neoplasias da Mama/genética , Proteínas Desgrenhadas/genética , RNA Polimerase I/genética , Transcrição Gênica , Proteína Wnt-5a/genética , Neoplasias da Mama/patologia , Cromatina/genética , DNA Ribossômico/genética , Proteínas Desgrenhadas/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Células MCF-7 , Região Organizadora do Nucléolo/genética , Regiões Promotoras Genéticas , Ligação Proteica , RNA Ribossômico/genética , Sirtuínas/genética , Via de Sinalização Wnt/genética , Proteína Wnt-5a/metabolismo
5.
Cell Microbiol ; 19(2)2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27527752

RESUMO

The coxsackievirus and adenovirus receptor (CAR), in addition to serving as viral receptor, is a component of tight junctions and plays an important role in tissue homeostasis. Defects in the cystic fibrosis transmembrane regulator (CFTR) in lung epithelial cells are linked to inflammation and susceptibility for respiratory tract infections. Here, we demonstrate that CAR expression and infectivity with adenovirus (Ad) are increased in cystic fibrosis airway epithelial cells. Inhibition of CFTR or histone deacetylase (HDAC) enhanced CAR expression while CFTR overexpression or restoration of the diminished HDAC activity in cystic fibrosis cells reduced CAR expression. This connects the CFTR to CAR expression and infectivity with adenovirus through HDAC.


Assuntos
Proteína de Membrana Semelhante a Receptor de Coxsackie e Adenovirus/biossíntese , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Fibrose Cística/patologia , Células Epiteliais/metabolismo , Regulação da Expressão Gênica , Adenoviridae/crescimento & desenvolvimento , Linhagem Celular , Humanos
6.
Proc Natl Acad Sci U S A ; 110(29): 11851-6, 2013 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-23818587

RESUMO

Peptidylarginine deiminase 4 (PAD4) is a Ca(2+)-dependent enzyme that converts arginine and methylarginine residues to citrulline, with histone proteins being among its best-described substrates to date. However, the biological function of this posttranslational modification, either in histones or in nonhistone proteins, is poorly understood. Here, we show that PAD4 recognizes, binds, and citrullinates glycogen synthase kinase-3ß (GSK3ß), both in vitro and in vivo. Among other functions, GSK3ß is a key regulator of transcription factors involved in tumor progression, and its dysregulation has been associated with progression of human cancers. We demonstrate that silencing of PAD4 in breast cancer cells leads to a striking reduction of nuclear GSK3ß protein levels, increased TGF-ß signaling, induction of epithelial-to-mesenchymal transition, and production of more invasive tumors in xenograft assays. Moreover, in breast cancer patients, reduction of PAD4 and nuclear GSK3ß is associated with increased tumor invasiveness. We propose that PAD4-mediated citrullination of GSK3ß is a unique posttranslational modification that regulates its nuclear localization and thereby plays a critical role in maintaining an epithelial phenotype. We demonstrate a dynamic and previously unappreciated interplay between histone-modifying enzymes, citrullination of nonhistone proteins, and epithelial-to-mesenchymal transition.


Assuntos
Citrulina/metabolismo , Transição Epitelial-Mesenquimal/fisiologia , Quinase 3 da Glicogênio Sintase/metabolismo , Hidrolases/metabolismo , Transdução de Sinais/fisiologia , Fator de Crescimento Transformador beta/metabolismo , Ionóforos de Cálcio , Imunofluorescência , Técnicas de Silenciamento de Genes , Glicogênio Sintase Quinase 3 beta , Humanos , Immunoblotting , Imuno-Histoquímica , Imunoprecipitação , Células MCF-7 , Espectrometria de Massas , Microscopia de Interferência , Mutagênese Sítio-Dirigida , Proteína-Arginina Desiminase do Tipo 4 , Desiminases de Arginina em Proteínas , Reação em Cadeia da Polimerase em Tempo Real , Estatísticas não Paramétricas
8.
Semin Cancer Biol ; 22(5-6): 385-95, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22613484

RESUMO

Tumor metastases and epithelial to mesenchymal transition (EMT) involve tumor cell invasion and migration through the dense collagen-rich extracellular matrix surrounding the tumor. Little is neither known about the mechanobiological mechanisms involved in this process, nor the role of the mechanical forces generated by the cells in their effort to invade and migrate through the stroma. In this paper we propose a new fundamental mechanobiological mechanism involved in cancer growth and metastasis, which can be both protective or destructive depending on the magnitude of the forces generated by the cells. This new mechanobiological mechanism directly challenges current paradigms that are focused mainly on biological and biochemical mechanisms associated with tumor metastasis. Our new mechanobiological mechanism describes how tumor expansion generates mechanical forces within the stroma to not only resist tumor expansion but also inhibit or enhance tumor invasion by, respectively, inhibiting or enhancing matrix metalloproteinase (MMP) degradation of the tensed interstitial collagen. While this mechanobiological mechanism has not been previously applied to the study of tumor metastasis and EMT, it may have the potential to broaden our understanding of the tumor invasive process and assist in developing new strategies for preventing or treating cancer metastasis.


Assuntos
Metástase Neoplásica , Fenômenos Biomecânicos , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Movimento Celular , Colágeno/metabolismo , Transição Epitelial-Mesenquimal , Matriz Extracelular/metabolismo , Feminino , Humanos , Modelos Biológicos , Invasividade Neoplásica
9.
Front Cell Dev Biol ; 9: 728325, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34869315

RESUMO

Despite the significant advancements made in targeted anti-cancer therapy, drug resistance constitutes a multifaceted phenomenon leading to therapy failure and ultimately mortality. Emerging experimental evidence highlight a role of cholesterol metabolism in facilitating drug resistance in cancer. This review aims to describe the role of cholesterol in facilitating multi-drug resistance in cancer. We focus on specific signaling pathways that contribute to drug resistance and the link between these pathways and cholesterol. Additionally, we briefly discuss the molecular mechanisms related to the epithelial-mesenchymal transition (EMT), and the documented link between EMT, metastasis and drug resistance. We illustrate this by specifically focusing on hypoxia and the role it plays in influencing cellular cholesterol content following EMT induction. Finally, we provide a proposed model delineating the crucial role of cholesterol in EMT and discuss whether targeting cholesterol could serve as a novel means of combatting drug resistance in cancer progression and metastasis.

10.
Nat Commun ; 11(1): 1416, 2020 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-32184389

RESUMO

The kinase mTOR complex 1 (mTORC1) promotes cellular growth and is frequently dysregulated in cancers. In response to nutrients, mTORC1 is activated on lysosomes by Rag and Rheb guanosine triphosphatases (GTPases) and drives biosynthetic processes. How limitations in nutrients suppress mTORC1 activity remains poorly understood. We find that when amino acids are limited, the Rap1-GTPases confine lysosomes to the perinuclear region and reduce lysosome abundance, which suppresses mTORC1 signaling. Rap1 activation, which is independent of known amino acid signaling factors, limits the lysosomal surface available for mTORC1 activation. Conversely, Rap1 depletion expands the lysosome population, which markedly increases association between mTORC1 and its lysosome-borne activators, leading to mTORC1 hyperactivity. Taken together, we establish Rap1 as a critical coordinator of the lysosomal system, and propose that aberrant changes in lysosomal surface availability can impact mTORC1 signaling output.


Assuntos
Aminoácidos/metabolismo , Lisossomos/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Proteínas rap de Ligação ao GTP/metabolismo , Proteínas rap1 de Ligação ao GTP/metabolismo , Humanos , Lisossomos/enzimologia , Lisossomos/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Transdução de Sinais , Proteínas rap de Ligação ao GTP/genética , Proteínas rap1 de Ligação ao GTP/genética
11.
Mol Cancer Res ; 18(10): 1522-1533, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32665429

RESUMO

Children suffering from neurologic cancers undergoing chemotherapy and radiotherapy are at high risk of reduced neurocognitive abilities likely via damage to proliferating neural stem cells (NSC). Therefore, strategies to protect NSCs are needed. We argue that induced cell-cycle arrest/quiescence in NSCs during cancer treatment can represent such a strategy. Here, we show that hyperpolarization-activated cyclic nucleotide-gated (HCN) ion channels are dynamically expressed over the cell cycle in NSCs, depolarize the membrane potential, underlie spontaneous calcium oscillations and are required to maintain NSCs in the actively proliferating pool. Hyperpolarizing pharmacologic inhibition of HCN channels during exposure to ionizing radiation protects NSCs cells in neurogenic brain regions of young mice. In contrast, brain tumor-initiating cells, which also express HCN channels, remain proliferative during HCN inhibition. IMPLICATIONS: Our finding that NSCs can be selectively rescued while cancer cells remain sensitive to the treatment, provide a foundation for reduction of cognitive impairment in children with neurologic cancers.


Assuntos
Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/metabolismo , Neoplasias/tratamento farmacológico , Células-Tronco Neurais/metabolismo , Animais , Proliferação de Células , Humanos , Camundongos
13.
Cancer Res ; 79(1): 47-60, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30385615

RESUMO

Tight junctions (TJ) act as hubs for intracellular signaling pathways controlling epithelial cell fate and function. Deregulation of TJ is a hallmark of epithelial-mesenchymal transition (EMT), which contributes to carcinoma progression and metastasis. However, the signaling mechanisms linking TJ to the induction of EMT are not understood. Here, we identify a TJ-based signalosome, which controls AKT signaling and EMT in breast cancer. The coxsackie and adenovirus receptor (CXADR), a TJ protein with an essential yet uncharacterized role in organogenesis and tissue homeostasis, was identified as a key component of the signalosome. CXADR regulated the stability and function of the phosphatases and AKT inhibitors PTEN and PHLPP2. Loss of CXADR led to hyperactivation of AKT and sensitized cells to TGFß1-induced EMT. Conversely, restoration of CXADR stabilized PHLPP2 and PTEN, inhibited AKT, and promoted epithelial differentiation. Loss of CXADR in luminal A breast cancer correlated with loss of PHLPP2 and PTEN and poor prognosis. These results show that CXADR promotes the formation of an AKT-inhibitory signalosome at TJ and regulates epithelial-mesenchymal plasticity in breast cancer cells. Moreover, loss of CXADR might be used as a prognostic marker in luminal breast cancer. SIGNIFICANCE: The tight junction protein CXADR controls epithelial-mesenchymal plasticity in breast cancer by stabilizing the AKT regulators PTEN and PHLPP2.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/79/1/47/F1.large.jpg.


Assuntos
Neoplasias da Mama/patologia , Proteína de Membrana Semelhante a Receptor de Coxsackie e Adenovirus/metabolismo , Transição Epitelial-Mesenquimal , Regulação Neoplásica da Expressão Gênica , Junções Íntimas/patologia , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Diferenciação Celular , Movimento Celular , Proteína de Membrana Semelhante a Receptor de Coxsackie e Adenovirus/genética , Proteína de Membrana Semelhante a Receptor de Coxsackie e Adenovirus/fisiologia , Feminino , Perfilação da Expressão Gênica , Humanos , Camundongos Endogâmicos C57BL , Camundongos Knockout , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , Fosfoproteínas Fosfatases/genética , Fosfoproteínas Fosfatases/metabolismo , Prognóstico , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Taxa de Sobrevida , Junções Íntimas/genética , Junções Íntimas/metabolismo , Células Tumorais Cultivadas
14.
Nat Commun ; 10(1): 2110, 2019 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-31068593

RESUMO

Ribosome biogenesis is a canonical hallmark of cell growth and proliferation. Here we show that execution of Epithelial-to-Mesenchymal Transition (EMT), a migratory cellular program associated with development and tumor metastasis, is fueled by upregulation of ribosome biogenesis during G1/S arrest. This unexpected EMT feature is independent of species and initiating signal, and is accompanied by release of the repressive nucleolar chromatin remodeling complex (NoRC) from rDNA, together with recruitment of the EMT-driving transcription factor Snai1 (Snail1), RNA Polymerase I (Pol I) and the Upstream Binding Factor (UBF). EMT-associated ribosome biogenesis is also coincident with increased nucleolar recruitment of Rictor, an essential component of the EMT-promoting mammalian target of rapamycin complex 2 (mTORC2). Inhibition of rRNA synthesis in vivo differentiates primary tumors to a benign, Estrogen Receptor-alpha (ERα) positive, Rictor-negative phenotype and reduces metastasis. These findings implicate the EMT-associated ribosome biogenesis program with cellular plasticity, de-differentiation, cancer progression and metastatic disease.


Assuntos
Transição Epitelial-Mesenquimal/fisiologia , Pontos de Checagem da Fase G1 do Ciclo Celular/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Regulação Neoplásica da Expressão Gênica , Ribossomos/metabolismo , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Diferenciação Celular/fisiologia , Linhagem Celular Tumoral/transplante , Movimento Celular/fisiologia , Nucléolo Celular/metabolismo , Embrião de Galinha , Proteínas Cromossômicas não Histona/metabolismo , DNA Ribossômico/metabolismo , Modelos Animais de Doenças , Feminino , Perfilação da Expressão Gênica , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , RNA Ribossômico/metabolismo , Ribossomos/genética
15.
Sci Adv ; 4(2): eaao0665, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29503865

RESUMO

The ribosome, the integration point for protein synthesis in the cell, is conventionally considered a homogeneous molecular assembly that only passively contributes to gene expression. Yet, epigenetic features of the ribosomal DNA (rDNA) operon and changes in the ribosome's molecular composition have been associated with disease phenotypes, suggesting that the ribosome itself may possess inherent regulatory capacity. Analyzing whole-genome sequencing data from the 1000 Genomes Project and the Mouse Genomes Project, we find that rDNA copy number varies widely across individuals, and we identify pervasive intra- and interindividual nucleotide variation in the 5S, 5.8S, 18S, and 28S ribosomal RNA (rRNA) genes of both human and mouse. Conserved rRNA sequence heterogeneities map to functional centers of the assembled ribosome, variant rRNA alleles exhibit tissue-specific expression, and ribosomes bearing variant rRNA alleles are present in the actively translating ribosome pool. These findings provide a critical framework for exploring the possibility that the expression of genomically encoded variant rRNA alleles gives rise to physically and functionally heterogeneous ribosomes that contribute to mammalian physiology and human disease.


Assuntos
Alelos , Regulação da Expressão Gênica , Mutação/genética , Especificidade de Órgãos/genética , RNA Ribossômico/genética , Animais , Sequência de Bases , Cromossomos Humanos/genética , Sequência Conservada/genética , DNA Ribossômico/genética , Evolução Molecular , Dosagem de Genes , Perfilação da Expressão Gênica , Genoma Humano , Células HEK293 , Humanos , Camundongos , Óperon/genética , Biossíntese de Proteínas , Subunidades Proteicas/genética , Processamento Pós-Transcricional do RNA/genética , Ribossomos/metabolismo
16.
Cell Rep ; 25(1): 236-248.e6, 2018 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-30282032

RESUMO

Prevailing dogma holds that ribosomes are uniform in composition and function. Here, we show that nutrient limitation-induced stress in E. coli changes the relative expression of rDNA operons to alter the rRNA composition within the actively translating ribosome pool. The most upregulated operon encodes the unique 16S rRNA, rrsH, distinguished by conserved sequence variation within the small ribosomal subunit. rrsH-bearing ribosomes affect the expression of functionally coherent gene sets and alter the levels of the RpoS sigma factor, the master regulator of the general stress response. These impacts are associated with phenotypic changes in antibiotic sensitivity, biofilm formation, and cell motility and are regulated by stress response proteins, RelA and RelE, as well as the metabolic enzyme and virulence-associated protein, AdhE. These findings establish that endogenously encoded, naturally occurring rRNA sequence variation can modulate ribosome function, central aspects of gene expression regulation, and cellular physiology.


Assuntos
Escherichia coli/genética , Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , RNA Ribossômico/genética , RNA Ribossômico/metabolismo , Modelos Moleculares , Óperon , Fenótipo
18.
Cancer Res ; 77(7): 1741-1752, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28087597

RESUMO

Glioma-initiating cells (GIC) are considered the underlying cause of recurrences of aggressive glioblastomas, replenishing the tumor population and undermining the efficacy of conventional chemotherapy. Here we report the discovery that inhibiting T-type voltage-gated Ca2+ and KCa channels can effectively induce selective cell death of GIC and increase host survival in an orthotopic mouse model of human glioma. At present, the precise cellular pathways affected by the drugs affecting these channels are unknown. However, using cell-based assays and integrated proteomics, phosphoproteomics, and transcriptomics analyses, we identified the downstream signaling events these drugs affect. Changes in plasma membrane depolarization and elevated intracellular Na+, which compromised Na+-dependent nutrient transport, were documented. Deficits in nutrient deficit acted in turn to trigger the unfolded protein response and the amino acid response, leading ultimately to nutrient starvation and GIC cell death. Our results suggest new therapeutic targets to attack aggressive gliomas. Cancer Res; 77(7); 1741-52. ©2017 AACR.


Assuntos
Aminoácidos/metabolismo , Neoplasias Encefálicas/tratamento farmacológico , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio Tipo T/fisiologia , Glioma/tratamento farmacológico , Canais de Potássio Cálcio-Ativados/antagonistas & inibidores , Resposta a Proteínas não Dobradas/efeitos dos fármacos , Animais , Transporte Biológico , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Morte Celular , Linhagem Celular Tumoral , Di-Hidropiridinas/farmacologia , Glioma/metabolismo , Glioma/patologia , Humanos , Camundongos , Micotoxinas/farmacologia , Células-Tronco Neoplásicas/patologia , Proteômica , Sódio/metabolismo
19.
Genome Biol Evol ; 8(3): 742-52, 2016 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-26802429

RESUMO

Escherichia coli strain MRE600 was originally identified for its low RNase I activity and has therefore been widely adopted by the biomedical research community as a preferred source for the expression and purification of transfer RNAs and ribosomes. Despite its widespread use, surprisingly little information about its genome or genetic content exists. Here, we present the first de novo assembly and description of the MRE600 genome and epigenome. To provide context to these studies of MRE600, we include comparative analyses with E. coli K-12 MG1655 (K12). Pacific Biosciences Single Molecule, Real-Time sequencing reads were assembled into one large chromosome (4.83 Mb) and three smaller plasmids (89.1, 56.9, and 7.1 kb). Interestingly, the 7.1-kb plasmid possesses genes encoding a colicin E1 protein and its associated immunity protein. The MRE600 genome has a G + C content of 50.8% and contains a total of 5,181 genes, including 4,913 protein-encoding genes and 268 RNA genes. We identified 41,469 modified DNA bases (0.83% of total) and found that MRE600 lacks the gene for type I methyltransferase, EcoKI. Phylogenetic, taxonomic, and genetic analyses demonstrate that MRE600 is a divergent E. coli strain that displays features of the closely related genus, Shigella. Nevertheless, comparative analyses between MRE600 and E. coli K12 show that these two strains exhibit nearly identical ribosomal proteins, ribosomal RNAs, and highly homologous tRNA species. Substantiating prior suggestions that MRE600 lacks RNase I activity, the RNase I-encoding gene, rna, contains a single premature stop codon early in its open-reading frame.


Assuntos
Escherichia coli K12/genética , Ribonuclease Pancreático/genética , Proteínas Ribossômicas/genética , DNA Metiltransferases Sítio Específica (Adenina-Específica)/genética , Epigenômica , Escherichia coli K12/enzimologia , Variação Genética , Anotação de Sequência Molecular , Filogenia , Plasmídeos/genética , Ribossomos/genética , Shigella/genética
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