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1.
Genetics ; 217(1): 1-17, 2021 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-33683371

RESUMO

We describe here phase-separated subnuclear organelles in the nematode Caenorhabditis elegans, which we term NUN (NUclear Nervous system-specific) bodies. Unlike other previously described subnuclear organelles, NUN bodies are highly cell type specific. In fully mature animals, 4-10 NUN bodies are observed exclusively in the nucleus of neuronal, glial and neuron-like cells, but not in other somatic cell types. Based on co-localization and genetic loss of function studies, NUN bodies are not related to other previously described subnuclear organelles, such as nucleoli, splicing speckles, paraspeckles, Polycomb bodies, promyelocytic leukemia bodies, gems, stress-induced nuclear bodies, or clastosomes. NUN bodies form immediately after cell cycle exit, before other signs of overt neuronal differentiation and are unaffected by the genetic elimination of transcription factors that control many other aspects of neuronal identity. In one unusual neuron class, the canal-associated neurons, NUN bodies remodel during larval development, and this remodeling depends on the Prd-type homeobox gene ceh-10. In conclusion, we have characterized here a novel subnuclear organelle whose cell type specificity poses the intriguing question of what biochemical process in the nucleus makes all nervous system-associated cells different from cells outside the nervous system.


Assuntos
Espaço Intranuclear/ultraestrutura , Neurônios/ultraestrutura , Animais , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Ciclo Celular , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Espaço Intranuclear/metabolismo , Neuroglia/ultraestrutura
2.
Am J Hum Genet ; 108(2): 357-367, 2021 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-33508234

RESUMO

Focal segmental glomerulosclerosis (FSGS) is the main pathology underlying steroid-resistant nephrotic syndrome (SRNS) and a leading cause of chronic kidney disease. Monogenic forms of pediatric SRNS are predominantly caused by recessive mutations, while the contribution of de novo variants (DNVs) to this trait is poorly understood. Using exome sequencing (ES) in a proband with FSGS/SRNS, developmental delay, and epilepsy, we discovered a nonsense DNV in TRIM8, which encodes the E3 ubiquitin ligase tripartite motif containing 8. To establish whether TRIM8 variants represent a cause of FSGS, we aggregated exome/genome-sequencing data for 2,501 pediatric FSGS/SRNS-affected individuals and 48,556 control subjects, detecting eight heterozygous TRIM8 truncating variants in affected subjects but none in control subjects (p = 3.28 × 10-11). In all six cases with available parental DNA, we demonstrated de novo inheritance (p = 2.21 × 10-15). Reverse phenotyping revealed neurodevelopmental disease in all eight families. We next analyzed ES from 9,067 individuals with epilepsy, yielding three additional families with truncating TRIM8 variants. Clinical review revealed FSGS in all. All TRIM8 variants cause protein truncation clustering within the last exon between residues 390 and 487 of the 551 amino acid protein, indicating a correlation between this syndrome and loss of the TRIM8 C-terminal region. Wild-type TRIM8 overexpressed in immortalized human podocytes and neuronal cells localized to nuclear bodies, while constructs harboring patient-specific variants mislocalized diffusely to the nucleoplasm. Co-localization studies demonstrated that Gemini and Cajal bodies frequently abut a TRIM8 nuclear body. Truncating TRIM8 DNVs cause a neuro-renal syndrome via aberrant TRIM8 localization, implicating nuclear bodies in FSGS and developmental brain disease.


Assuntos
Proteínas de Transporte/genética , Deficiências do Desenvolvimento/genética , Epilepsia/genética , Glomerulosclerose Segmentar e Focal/genética , Espaço Intranuclear/metabolismo , Síndrome Nefrótica/genética , Síndrome Nefrótica/metabolismo , Proteínas do Tecido Nervoso/genética , Adulto , Animais , Proteínas de Transporte/química , Proteínas de Transporte/metabolismo , Linhagem Celular , Criança , Pré-Escolar , Códon sem Sentido , Deficiências do Desenvolvimento/metabolismo , Epilepsia/metabolismo , Feminino , Glomerulosclerose Segmentar e Focal/metabolismo , Humanos , Rim/metabolismo , Masculino , Camundongos , Mutação , Proteínas do Tecido Nervoso/química , Proteínas do Tecido Nervoso/metabolismo , Fenótipo , Podócitos/metabolismo , Sequenciamento Completo do Exoma
3.
Diagn Cytopathol ; 49(2): E65-E70, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32816379

RESUMO

Follicular dendritic cell sarcoma (FDCS) is a rare malignant neoplasm of follicular dendritic cell origin which can present a diagnostic challenge. Due to the rarity of this neoplasm, its molecular pathogenesis has not been fully elaborated. A previous series of 13 cases reported that 38% contained mutations of genes encoding proteins involved in negative regulation of NF-κB. NF-κB is a family of transcription factors regulated through multiple cellular processes known as the canonical and noncanonical pathways. Here we present the case of a 62-year-old man who presented with abdominal pain and systemic symptoms and was found to have a mass in the porta hepatis. Fine needle aspiration cytology demonstrated a spindle cell neoplasm with vesicular chromatin and prominent nucleoli with admixed lymphocytes. Surgical resection showed an intranodal, 7.3 × 5.5 × 3.5 cm, solid mass composed of plump, spindle to histiocytoid cells with ovoid nuclei and small, prominent nucleoli arranged in a whorled and fascicular pattern. The lesional cells stained positively for CD21, CD23, and CD35 by immunohistochemistry, consistent with a diagnosis of FDCS. Next-generation sequencing revealed pathologic mutations in three genes involved in NF-κB regulation pathways: NFKBIA, TNFAIP3, and TRAF3. A pathologic TP53 mutation was also identified. This case report supports prior associations of the NF-κB pathway dysregulation and FDCS. Additionally, it is the first reported FDCS case with TRAF3 mutation as well as the first reported case to suggest disruption in both the canonical and noncanonical NF-κB pathways in the same lesion.


Assuntos
Sarcoma de Células Dendríticas Foliculares/diagnóstico , Sarcoma de Células Dendríticas Foliculares/patologia , Espaço Intranuclear/patologia , Biópsia por Agulha Fina/métodos , Sarcoma de Células Dendríticas Foliculares/metabolismo , Humanos , Imuno-Histoquímica/métodos , Masculino , Pessoa de Meia-Idade , NF-kappa B/metabolismo , Transdução de Sinais/fisiologia
4.
Int J Mol Sci ; 20(12)2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31248120

RESUMO

Polyphosphoinositides (PPIns) are a family of seven lipid messengers that regulate a vast array of signalling pathways to control cell proliferation, migration, survival and differentiation. PPIns are differentially present in various sub-cellular compartments and, through the recruitment and regulation of specific proteins, are key regulators of compartment identity and function. Phosphoinositides and the enzymes that synthesise and degrade them are also present in the nuclear membrane and in nuclear membraneless compartments such as nuclear speckles. Here we discuss how PPIns in the nucleus are modulated in response to external cues and how they function to control downstream signalling. Finally we suggest a role for nuclear PPIns in liquid phase separations that are involved in the formation of membraneless compartments within the nucleus.


Assuntos
Núcleo Celular/metabolismo , Metabolismo dos Lipídeos , Fosfatidilinositóis/metabolismo , Animais , Fenômenos Químicos , Biologia Computacional , Humanos , Espaço Intranuclear/metabolismo , Redes e Vias Metabólicas , Membrana Nuclear/metabolismo , Fosfatidilinositol 4,5-Difosfato/química , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fosfatidilinositóis/química , Transdução de Sinais
5.
J Cell Sci ; 132(5)2019 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-30745340

RESUMO

The GGGGCC (G4C2) repeat expansion mutation in the C9ORF72 gene is the most common genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Transcription of the repeat and formation of nuclear RNA foci, which sequester specific RNA-binding proteins, is one of the possible pathological mechanisms. Here, we show that (G4C2) n repeat RNA predominantly associates with essential paraspeckle proteins SFPQ, NONO, RBM14, FUS and hnRNPH and colocalizes with known paraspeckle-associated RNA hLinc-p21. As formation of paraspeckles in motor neurons has been associated with early phases of ALS, we investigated the extent of similarity between paraspeckles and (G4C2) n RNA foci. Overexpression of (G4C2)72 RNA results in their increased number and colocalization with SFPQ-stained nuclear bodies. These paraspeckle-like (G4C2)72 RNA foci form independently of the known paraspeckle scaffold, the long non-coding RNA NEAT1 Moreover, the knockdown of SFPQ protein in C9ORF72 expansion mutation-positive fibroblasts significantly reduces the number of (G4C2) n RNA foci. In conclusion, (G4C2) n RNA foci have characteristics of paraspeckles, which suggests that both RNA foci and paraspeckles play roles in FTD and ALS, and implies approaches for regulation of their formation.


Assuntos
Esclerose Amiotrófica Lateral/genética , Proteína C9orf72/genética , Demência Frontotemporal/genética , Neurônios Motores/fisiologia , Complexos Multiproteicos/metabolismo , Mutação/genética , RNA Nuclear/metabolismo , Esclerose Amiotrófica Lateral/metabolismo , Animais , Proteína C9orf72/metabolismo , Células Cultivadas , Proteínas de Ligação a DNA/metabolismo , Demência Frontotemporal/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Espaço Intranuclear , Camundongos , Fator de Processamento Associado a PTB/metabolismo , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , RNA Nuclear/genética , Proteína FUS de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/metabolismo , Ratos
6.
PLoS Pathog ; 15(2): e1007590, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30802273

RESUMO

Subnuclear promyelocytic leukemia (PML) nuclear bodies (NBs) are targeted by many DNA viruses after nuclear delivery. PML protein is essential for formation of PML NBs. Sp100 and Small Ubiquitin-Like Modifier (SUMO) are also permanently residing within PML NBs. Often, large DNA viruses disassemble and reorganize PML NBs to counteract their intrinsic antiviral activity and support establishment of infection. However, human papillomavirus (HPV) requires PML protein to retain incoming viral DNA in the nucleus for subsequent efficient transcription. In contrast, Sp100 was identified as a restriction factor for HPV. These findings suggested that PML NBs are important regulators of early stages of the HPV life cycle. Nuclear delivery of incoming HPV DNA requires mitosis. Viral particles are retained within membrane-bound transport vesicles throughout mitosis. The viral genome is released from transport vesicles by an unknown mechanism several hours after nuclear envelope reformation. The minor capsid protein L2 mediates intracellular transport by becoming transmembranous in the endocytic compartment. Herein, we tested our hypothesis that PML protein is recruited to incoming viral genome prior to egress from transport vesicles. High-resolution microscopy revealed that PML protein, SUMO-1, and Sp100 are recruited to incoming viral genomes, rather than viral genomes being targeted to preformed PML NBs. Differential immunofluorescent staining suggested that PML protein and SUMO-1 associated with transport vesicles containing viral particles prior to egress, implying that recruitment is likely mediated by L2 protein. In contrast, Sp100 recruitment to HPV-harboring PML NBs occurred after release of viral genomes from transport vesicles. The delayed recruitment of Sp100 is specific for HPV-associated PML NBs. These data suggest that the virus continuously resides within a protective environment until the transport vesicle breaks down in late G1 phase and imply that HPV might modulate PML NB assembly to achieve establishment of infection and the shift to viral maintenance.


Assuntos
Papillomaviridae/genética , Papillomaviridae/metabolismo , Proteína da Leucemia Promielocítica/metabolismo , Antígenos Nucleares/metabolismo , Autoantígenos/metabolismo , Proteínas do Capsídeo , Núcleo Celular , Genoma Viral , Humanos , Corpos de Inclusão Intranuclear , Espaço Intranuclear , Proteínas Nucleares , Papillomaviridae/patogenicidade , Proteína da Leucemia Promielocítica/fisiologia , Proteína SUMO-1/metabolismo , Fatores de Transcrição , Proteínas Supressoras de Tumor , Replicação Viral
7.
PLoS One ; 13(12): e0209195, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30557374

RESUMO

Ribonucleoprotein (RNP) granules are higher order assemblies of RNA, RNA-binding proteins, and other proteins, that regulate the transcriptome and protect RNAs from environmental challenge. There is a diverse range of RNP granules, many cytoplasmic, which provide various levels of regulation of RNA metabolism. Here we present evidence that the yeast transcription termination factor, Nab3, is targeted to intranuclear granules in response to glucose starvation by Nab3's proline/glutamine-rich, prion-like domain (PrLD) which can assemble into amyloid in vitro. Localization to the granule is reversible and sensitive to the chemical probe 1,6 hexanediol suggesting condensation is driven by phase separation. Nab3's RNA recognition motif is also required for localization as seen for other PrLD-containing RNA-binding proteins that phase separate. Although the PrLD is necessary, it is not sufficient to localize to the granule. A heterologous PrLD that functionally replaces Nab3's essential PrLD, directed localization to the nuclear granule, however a chimeric Nab3 molecule with a heterologous PrLD that cannot restore termination function or viability, does not form granules. The Nab3 nuclear granule shows properties similar to well characterized cytoplasmic compartments formed by phase separation, suggesting that, as seen for other elements of the transcription machinery, termination factor condensation is functionally important.


Assuntos
Glucose/deficiência , Espaço Intranuclear/metabolismo , Proteínas Nucleares/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Expressão Gênica , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Proteínas Nucleares/genética , Príons/metabolismo , Domínios Proteicos , Proteínas de Ligação a RNA/genética , Saccharomyces cerevisiae , Proteínas de Saccharomyces cerevisiae/genética , Estresse Fisiológico/fisiologia
8.
J Cell Biol ; 217(11): 3912-3929, 2018 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-30194269

RESUMO

Nuclear speckles (NSs) serve as splicing factor storage sites. In this study, we unexpectedly found that many endogenous intronless mRNAs, which do not undergo splicing, associate with NSs. These associations do not require transcription, polyadenylation, or the polyA tail. Rather, exonic splicing enhancers present in intronless mRNAs and their binding partners, SR proteins, promote intronless mRNA localization to NSs. Significantly, speckle targeting of mRNAs promotes the recruitment of the TREX export complex and their TREX-dependent nuclear export. Furthermore, TREX, which accumulates in NSs, is required for releasing intronless mRNAs from NSs, whereas NXF1, which is mainly detected at nuclear pores, is not. Upon NXF1 depletion, the TREX protein UAP56 loses speckle concentration but coaccumulates with intronless mRNAs and polyA RNAs in the nucleoplasm, and these RNAs are trapped in NSs upon UAP56 codepletion. We propose that the export-competent messenger RNP assembly mainly occurs in NSs for intronless mRNAs and that entering NSs serves as a quality control step in mRNA export.


Assuntos
RNA Helicases DEAD-box/metabolismo , Espaço Intranuclear/metabolismo , Poro Nuclear/metabolismo , Proteínas de Transporte Nucleocitoplasmático/metabolismo , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/metabolismo , Transporte Ativo do Núcleo Celular/fisiologia , RNA Helicases DEAD-box/genética , Células HeLa , Humanos , Poro Nuclear/genética , Proteínas de Transporte Nucleocitoplasmático/genética , RNA Mensageiro/genética , Proteínas de Ligação a RNA/genética
9.
Biochem Pharmacol ; 158: 141-152, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30096289

RESUMO

Patients undergoing surgery can suffer from various complications, including post-operative bleeding, local or systematic infection, and neurologic disorders. Major surgery can initiate innate immune responses and trigger overproduction of inflammatory mediators, which can contribute to organ dysfunction. Inflammasomes are innate immune complexes, which are connected to the pathogenesis of various diseases, including atherosclerosis, hemorrhagic brain injury, and Alzheimer's disease. In the present study, we hypothesized that nucleotide-binding oligomerization domain-containing-like receptor protein (NLRP) inflammasomes may have a role in the pathological effects of surgery. Therefore, we designed a protein inhibitor of nuclear factor kappa B (NF-κB) p65 transcripts, called nt-p65-TMD (nuclear transducible (nt) transcription modulated domain (TMD) of RelA (p65)), that can penetrate the nucleus, and evaluated its therapeutic efficacy for dampening surgery-induced inflammasome activation. It was found that the nt-p65-TMD significantly reduced the NLRP1 inflammasome complex components (NLRP1, ASC, and Caspase-1) and interleukin (IL)-1ß and IL-18 productions in the spleen after surgery. In the spleen, specific cell population and selective mediators were altered after surgery with/without nt-p65-TMD treatment. Also, we found that treatment of nt-p65-TMD decreased cell death in the spleen after surgery. Therefore, nt-p65-TMD is a potential novel strategy for reducing surgery-induced NLRP1 inflammasome and complications.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Inflamassomos/metabolismo , Espaço Intranuclear/metabolismo , Complicações Pós-Operatórias/tratamento farmacológico , Complicações Pós-Operatórias/metabolismo , Fator de Transcrição RelA/administração & dosagem , Abdome/cirurgia , Proteínas Adaptadoras de Transdução de Sinal/antagonistas & inibidores , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Proteínas Reguladoras de Apoptose/antagonistas & inibidores , Proteínas Reguladoras de Apoptose/metabolismo , Inflamassomos/antagonistas & inibidores , Intestinos/cirurgia , Espaço Intranuclear/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos ICR , Complicações Pós-Operatórias/etiologia
10.
J Mol Biol ; 430(23): 4711-4729, 2018 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-29758260

RESUMO

The formation of membraneless organelles (MLOs) by phase separation has emerged as a new way of organizing the cytoplasm and nucleoplasm of cells. Examples of MLOs forming via phase separation are nucleoli in the nucleus and stress granules in the cytoplasm. The main components of these MLOs are macromolecules such as RNAs and proteins. In order to assemble by phase separation, these proteins and RNAs have to undergo many cooperative interactions. These cooperative interactions are supported by specific molecular features within phase-separating proteins, such as multivalency and the presence of disordered domains that promote weak and transient interactions. However, these features also predispose phase-separating proteins to aberrant behavior. Indeed, evidence is emerging for a strong link between phase-separating proteins, MLOs, and age-related diseases. In this review, we discuss recent progress in understanding the formation, properties, and functions of MLOs. We pay special attention to the emerging link between MLOs and age-related diseases, and we explain how changes in the composition and physical properties of MLOs promote their conversion into an aberrant state. Furthermore, we discuss the key role of the protein quality control machinery in regulating the properties and functions of MLOs and thus in preventing age-related diseases.


Assuntos
Organelas/metabolismo , Proteínas/metabolismo , RNA/metabolismo , Animais , Citoplasma/metabolismo , Humanos , Espaço Intranuclear/metabolismo , Controle de Qualidade
11.
Sci Rep ; 8(1): 612, 2018 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-29330450

RESUMO

Y14 (RBM8A) is an RNA recognition motif-containing protein that forms heterodimers with MAGOH and serves as a core factor of the RNA surveillance machinery for the exon junction complex (EJC). The role of the Y14 C-terminal serine/arginine (RS) repeat-containing region, which has been reported to undergo modifications such as phosphorylation and methylation, has not been sufficiently investigated. Thus, we aimed to explore the functional significance of the Y14 C-terminal region. Deletion or dephosphorylation mimic mutants of the C-terminal region showed a shift in localization from the nucleoplasmic region; in addition, the C-terminal RS repeat-containing sequence itself exhibited the potential for nucleolar localization. Additionally, the regulation of Y14 localization by the C-terminal region was further found to be exquisitely controlled by MAGOH binding. Cumulatively, our findings, which demonstrated that Y14 localization is regulated not only by the previously reported N-terminal localization signal but also by the C-terminal RS repeat-containing region through phosphorylation and MAGOH binding to Y14, provide new insights for the mechanism of localization of short RS repeat-containing proteins.


Assuntos
Espaço Intranuclear/metabolismo , Proteínas Nucleares/metabolismo , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/metabolismo , Arginina/metabolismo , Sítios de Ligação , Nucléolo Celular/metabolismo , Células HeLa , Humanos , Fosforilação , Ligação Proteica , Domínios Proteicos , Transporte Proteico , Proteínas de Ligação a RNA/genética , Serina/metabolismo
12.
Mutat Res ; 809: 99-107, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-28521962

RESUMO

In the nucleus, there are several membraneless structures called nuclear bodies. Among them, promyelocytic leukemia nuclear bodies (PML-NBs) are involved in multiple genome maintenance pathways including the DNA damage response, DNA repair, telomere homeostasis, and p53-associated apoptosis. In response to DNA damage, PML-NBs are coalesced and divided by a fission mechanism, thus increasing their number. PML-NBs also play a role in repairing DNA double-strand breaks (DSBs) by homologous recombination (HR). Clinically, the dominant negative PML-RARα fusion protein expressed in acute promyelocytic leukemia (APL) inhibits the transactivation of downstream factors and disrupts PML function, revealing the tumor suppressor role of PML-NBs. All-trans retinoic acid and arsenic trioxide treatment has been implemented for promyelocytic leukemia to target the PML-RARα fusion protein. PML-NBs are associated with various factors implicated in genome maintenance, and are found at the sites of DNA damage. Their interaction with proteins such as p53 indicates that PML-NBs may play a significant role in apoptosis and cancer. Decades of research have revealed the importance of PML-NBs in diverse cellular pathways, yet the underlying molecular mechanisms and exact functions of PML-NBs remain elusive. In this review, PML protein modifications and the functional relevance of PML-NB and its associated factors in genome maintenance will be discussed.


Assuntos
Reparo do DNA , Instabilidade Genômica , Espaço Intranuclear , Leucemia Promielocítica Aguda , Proteínas de Fusão Oncogênica/metabolismo , Proteína da Leucemia Promielocítica/metabolismo , Animais , Apoptose , Quebras de DNA de Cadeia Dupla , Humanos , Espaço Intranuclear/metabolismo , Espaço Intranuclear/patologia , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/patologia , Proteínas de Fusão Oncogênica/genética , Proteína da Leucemia Promielocítica/genética , Homeostase do Telômero
13.
Nat Commun ; 7: 10291, 2016 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-26759081

RESUMO

The genomes of metazoa are organized at multiple scales. Many proteins that regulate genome architecture, including Polycomb group (PcG) proteins, form subnuclear structures. Deciphering mechanistic links between protein organization and chromatin architecture requires precise description and mechanistic perturbations of both. Using super-resolution microscopy, here we show that PcG proteins are organized into hundreds of nanoscale protein clusters. We manipulated PcG clusters by disrupting the polymerization activity of the sterile alpha motif (SAM) of the PcG protein Polyhomeotic (Ph) or by increasing Ph levels. Ph with mutant SAM disrupts clustering of endogenous PcG complexes and chromatin interactions while elevating Ph level increases cluster number and chromatin interactions. These effects can be captured by molecular simulations based on a previously described chromatin polymer model. Both perturbations also alter gene expression. Organization of PcG proteins into small, abundant clusters on chromatin through Ph SAM polymerization activity may shape genome architecture through chromatin interactions.


Assuntos
Cromatina/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/metabolismo , Espaço Intranuclear/metabolismo , Complexo Repressor Polycomb 1/metabolismo , Motivos de Aminoácidos , Animais , Linhagem Celular , Imunoprecipitação da Cromatina , Drosophila , Imunofluorescência , Microscopia , Simulação de Dinâmica Molecular , Imagem Óptica , Proteínas do Grupo Polycomb/metabolismo , Polímeros , Estrutura Quaternária de Proteína , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Análise de Sequência de RNA
14.
Arch Kriminol ; 238(1-2): 57-63, 2016 Aug.
Artigo em Inglês, Alemão | MEDLINE | ID: mdl-29894604

RESUMO

In a study on alcoholics, diabetics, cases of hypothermia, combinations of alcoholism, diabetes and hypothermia as well as 55 controls, ketone body measurements were performed in femoral vein blood, heart blood, vitreous humor, cerebrospinal fluid and urine. Histological investigations were carried out on the kidneys of the deceased. In addition to HE-staining, the cuts were stained with Sudan and PAS to allow differentiation between lipids and glycogens. The degree of stainability in the Sudan stains was correlated with the ketone body concentrations measured. In those cases in which elevated ketone body concentrations were measured, marked fat deposits in the renal tubular epithelial cells could be demonstrated with the Sudan staining method. The higher the stainability the higher the ketone body concentrations. The ketone body concentrations measured in the various body fluids correlated with the intensity of fat stainability.


Assuntos
Alcoolismo/patologia , Hipotermia/patologia , Espaço Intranuclear/patologia , Corpos Cetônicos/análise , Cetose/patologia , Lipídeos/análise , Vacúolos/patologia , Causas de Morte , Cetoacidose Diabética/patologia , Epitélio/patologia , Humanos , Túbulos Renais Proximais/patologia , Estudos Prospectivos
15.
Int J Mol Sci ; 16(12): 30343-61, 2015 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-26703574

RESUMO

An effective representation of a protein sequence plays a crucial role in protein sub-nuclear localization. The existing representations, such as dipeptide composition (DipC), pseudo-amino acid composition (PseAAC) and position specific scoring matrix (PSSM), are insufficient to represent protein sequence due to their single perspectives. Thus, this paper proposes two fusion feature representations of DipPSSM and PseAAPSSM to integrate PSSM with DipC and PseAAC, respectively. When constructing each fusion representation, we introduce the balance factors to value the importance of its components. The optimal values of the balance factors are sought by genetic algorithm. Due to the high dimensionality of the proposed representations, linear discriminant analysis (LDA) is used to find its important low dimensional structure, which is essential for classification and location prediction. The numerical experiments on two public datasets with KNN classifier and cross-validation tests showed that in terms of the common indexes of sensitivity, specificity, accuracy and MCC, the proposed fusing representations outperform the traditional representations in protein sub-nuclear localization, and the representation treated by LDA outperforms the untreated one.


Assuntos
Transporte Ativo do Núcleo Celular , Algoritmos , Espaço Intranuclear/metabolismo , Dipeptídeos/metabolismo , Modelos Teóricos
16.
Eur. j. anat ; 19(4): 361-370, oct. 2015. ilus, tab, graf
Artigo em Inglês | IBECS | ID: ibc-145665

RESUMO

This study deals with the application of methods of second-order stereology to investigate the spatial distribution of nuclei in normal prostate, prostatic intraepithelial neoplasia and adenocarcinoma. We aimed to identify differences related to the progression of premalignant lesions (PIN) to carcinoma, as well as the spatial changes in relation to tumour grade. Estimation of second-order stereology parameters, such as g(r), (pair correlation function), statistic M, and Clark-Evans aggregation index (CEAI) were employed to investigate the distribution of nuclei. Linear discriminant analysis (LDA) with M and CEAI as model variables was implemented to classify the cancer cases into two groups according to Gleason score. We found that the point processes of the nuclei in prostatic cancer and normal tissues differed by first-order as well as by second-order properties. In the PIN the mean g-values were intermediate between normal and cancer. The LDA indicates that M and CEAI were able to classify into the correct group of Gleason score more than 90% of the cases analysed. Cancer cases showing a higher degree of disorder in the spatial distribution of nuclei were significantly classified into the group of higher Gleason score. The nuclei in both normal and pathological prostate were not Poisson distributed. Additionally, we found that the progression from normal tissue to carcinoma was accompanied by a progressive increase in spatial disorder which is intermediate in pre-malignant lesions (PIN). The parameters employed were able to classify the cancer cases according to the Gleason score


No disponible


Assuntos
Humanos , Próstata/ultraestrutura , Neoplasias da Próstata/patologia , Neoplasia Prostática Intraepitelial/patologia , Espaço Intranuclear/ultraestrutura , Matriz Nuclear/ultraestrutura , Estatísticas não Paramétricas , Tipagem Molecular
17.
Cancer Sci ; 106(7): 848-56, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25891951

RESUMO

Nucleus accumbens associated 1 (NACC1) is a cancer-associated BTB/POZ (pox virus and zinc finger/bric-a-brac tramtrack broad complex) gene, and is involved in several cellular functions in neurons, cancer and stem cells. Some of the BTB/POZ proteins associated with cancer biology are SUMOylated, which appears to play an important role in transcription regulation. We show that NACC1 is SUMOylated on a phylogenetically conserved lysine (K167) out of three consensus SUMOylation motif sites. Amino acid substitution in the SIM sequence (SIM/M) within the BTB/POZ domain partially reduced K167 SUMOylation activity of NACC1. Overexpression of GFP-NACC1 fusion protein leads to formation of discrete nuclear foci similar to promyelocytic leukemia nuclear bodies (PML-NB), which colocalized with SUMO paralogues (SUMO1/2/3). Both NACC1 nuclear body formation and colocalization with SUMO paralogues were completely suppressed in the GFP-NACC1-SIM/M mutant, whereas they were partially maintained in the NACC1 K167R mutant. Confocal immunofluorescence analysis showed that endogenous and exogenous NACC1 proteins colocalized with endogenous PML protein. A pull-down assay revealed that the consensus motifs of the SUMO acceptor site at K167 and the SIM within the BTB/POZ domain were both necessary for efficient binding to PML protein. Our study demonstrates that NACC1 can be modified by SUMO paralogues, and cooperates with PML protein.


Assuntos
Proteínas de Neoplasias/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Repressoras/metabolismo , Sumoilação , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Enzimas de Conjugação de Ubiquitina/metabolismo , Sequência de Aminoácidos , Células HeLa , Humanos , Espaço Intranuclear/metabolismo , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/patologia , Células MCF-7 , Dados de Sequência Molecular , Proteína da Leucemia Promielocítica , Transporte Proteico
18.
Nat Commun ; 6: 5791, 2015 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-25557830

RESUMO

Processing of interleukin RNAs must be tightly controlled during the immune response. Here we report that a subnuclear body called the interleukin-6 and -10 splicing activating compartment (InSAC) is a nuclear site of cytokine RNA production and stability. Tat-activating regulatory DNA-binding protein-43 (TDP-43) acts as an InSAC scaffold that selectively associates with IL-6 and IL-10 RNAs in a sequence-specific manner. TDP-43 also recruits key spliceosomal components from Cajal bodies. LPS induces posttranslational modifications of TDP-43; in particular, TDP-43 ubiquitination provides a driving force for InSAC formation. As a consequence, in vivo depletion of TDP-43 leads to a dramatic reduction in the RNA processing and the protein levels of IL-6 in serum. Collectively, our findings highlight the importance of TDP-43-mediated InSAC biogenesis in immune regulation.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Imunidade Celular/genética , Espaço Intranuclear/fisiologia , Processamento Pós-Transcricional do RNA/fisiologia , Spliceossomos/metabolismo , Animais , Ensaio de Desvio de Mobilidade Eletroforética , Ensaio de Imunoadsorção Enzimática , Humanos , Immunoblotting , Imunoprecipitação , Hibridização in Situ Fluorescente , Interleucina-10/metabolismo , Interleucina-6/metabolismo , Lipopolissacarídeos , Camundongos , Camundongos Endogâmicos C57BL , Interferência de RNA , Reação em Cadeia da Polimerase em Tempo Real , Ubiquitinação
19.
Nucleic Acids Res ; 42(20): 12585-99, 2014 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-25342201

RESUMO

Successful progression through the cell cycle requires spatial and temporal regulation of gene transcript levels and the number, positions and condensation levels of chromosomes. Here we present a high resolution survey of genome interactions in Schizosaccharomyces pombe using synchronized cells to investigate cell cycle dependent changes in genome organization and transcription. Cell cycle dependent interactions were captured between and within S. pombe chromosomes. Known features of genome organization (e.g. the clustering of telomeres and retrotransposon long terminal repeats (LTRs)) were observed throughout the cell cycle. There were clear correlations between transcript levels and chromosomal interactions between genes, consistent with a role for interactions in transcriptional regulation at specific stages of the cell cycle. In silico reconstructions of the chromosome organization within the S. pombe nuclei were made by polymer modeling. These models suggest that groups of genes with high and low, or differentially regulated transcript levels have preferred positions within the S. pombe nucleus. We conclude that the S. pombe nucleus is spatially divided into functional sub-nuclear domains that correlate with gene activity. The observation that chromosomal interactions are maintained even when chromosomes are fully condensed in M phase implicates genome organization in epigenetic inheritance and bookmarking.


Assuntos
Ciclo Celular/genética , Núcleo Celular/genética , Cromossomos Fúngicos , Regulação Fúngica da Expressão Gênica , Schizosaccharomyces/genética , Genoma Fúngico , Espaço Intranuclear , Sequências Repetidas Terminais , Transcrição Genética
20.
Nucleic Acids Res ; 42(15): 9854-61, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25056310

RESUMO

Genomes undergo changes in organization as a result of gene duplications, chromosomal rearrangements and local mutations, among other mechanisms. In contrast to prokaryotes, in which genes of a common function are often organized in operons and reside contiguously along the genome, most eukaryotes show much weaker clustering of genes by function, except for few concrete functional groups. We set out to check systematically if there is a relation between gene function and gene organization in the human genome. We test this question for three types of functional groups: pairs of interacting proteins, complexes and pathways. We find a significant concentration of functional groups both in terms of their distance within the same chromosome and in terms of their dispersal over several chromosomes. Moreover, using Hi-C contact map of the tendency of chromosomal segments to appear close in the 3D space of the nucleus, we show that members of the same functional group that reside on distinct chromosomes tend to co-localize in space. The result holds for all three types of functional groups that we tested. Hence, the human genome shows substantial concentration of functional groups within chromosomes and across chromosomes in space.


Assuntos
Núcleo Celular/genética , Cromossomos Humanos , Genes , Genoma Humano , Humanos , Espaço Intranuclear , Mapeamento de Interação de Proteínas
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