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1.
Methods Mol Biol ; 2442: 713-726, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35320554

RESUMEN

Fractionation of HeLa cell nuclear extracts by glycerol gradient centrifugation separates endogenous uracil-rich small nuclear ribonucleoprotein complexes (U snRNP) into numerous particles sedimenting from 7S to greater than 60S. Complexes sedimenting at 10S contain a single U snRNP (U1 snRNP) and galectin-3. Addition of antibodies specific for galectin-3 to fractions containing these 10S complexes coprecipitates U1 snRNP, indicating that a fraction of the U1 snRNP is associated with this galectin. Galectin-3 has been shown by depletion-reconstitution studies to be an integral splicing component involved both in spliceosome assembly and splicing activity. The first step in initiation of spliceosome assembly is binding of U1 snRNP to the 5' splice site of the premessenger RNA substrate. The finding that U1 snRNP and galectin-3 are associated in splicing extracts hints that this complex affords a potential entry point for galectin-3 into the splicing pathway. Addition of U1 snRNP-galectin-3 complexes immunoselected from the 10S region of glycerol gradients to a U1-depleted nuclear extract initiates splicing activity with the formation of splicing intermediates and mature mRNA. This chapter describes the materials and methods for these experiments that document galectin-3-U1 snRNP complexes initiate the splicing reaction in a U1-depleted nuclear extract.


Asunto(s)
Galectina 3 , Empalme del ARN , Ribonucleoproteína Nuclear Pequeña U1 , Empalmosomas , Fraccionamiento Celular , Galectina 3/genética , Galectina 3/metabolismo , Células HeLa/metabolismo , Humanos , Espacio Intranuclear/química , Espacio Intranuclear/metabolismo , Precursores del ARN/metabolismo , Empalme del ARN/fisiología , Ribonucleoproteína Nuclear Pequeña U1/genética , Ribonucleoproteína Nuclear Pequeña U1/metabolismo , Empalmosomas/metabolismo , Uracilo/análisis , Uracilo/metabolismo
2.
Life Sci Alliance ; 4(11)2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34535568

RESUMEN

Proliferation of Plasmodium falciparum in red blood cells is the cause of malaria and is underpinned by an unconventional cell division mode, called schizogony. Contrary to model organisms, P. falciparum replicates by multiple rounds of nuclear divisions that are not interrupted by cytokinesis. Organization and dynamics of critical nuclear division factors remain poorly understood. Centriolar plaques, the centrosomes of P. falciparum, serve as microtubule organizing centers and have an acentriolar, amorphous structure. The small size of parasite nuclei has precluded detailed analysis of intranuclear microtubule organization by classical fluorescence microscopy. We apply recently developed super-resolution and time-lapse imaging protocols to describe microtubule reconfiguration during schizogony. Analysis of centrin, nuclear pore, and microtubule positioning reveals two distinct compartments of the centriolar plaque. Whereas centrin is extranuclear, we confirm by correlative light and electron tomography that microtubules are nucleated in a previously unknown and extended intranuclear compartment, which is devoid of chromatin but protein-dense. This study generates a working model for an unconventional centrosome and enables a better understanding about the diversity of eukaryotic cell division.


Asunto(s)
Centrosoma/fisiología , Espacio Intranuclear/metabolismo , Microtúbulos/metabolismo , División Celular/fisiología , Línea Celular , Centrosoma/metabolismo , Cromatina , Citocinesis , Humanos , Centro Organizador de los Microtúbulos/fisiología , Microtúbulos/fisiología , Poro Nuclear , Plasmodium falciparum/genética , Plasmodium falciparum/metabolismo
3.
STAR Protoc ; 2(1): 100378, 2021 03 19.
Artículo en Inglés | MEDLINE | ID: mdl-33778777

RESUMEN

Micronuclei are aberrant nuclear compartments that form when chromosomes or chromosome fragments fail to incorporate into a primary nucleus during mitotic exit. Ruptures at the micronuclear envelope are associated with DNA damage and activation of immune sensing pathways. To gain insights into these processes, we have developed a method to purify ruptured micronuclei. This method paves the way toward understanding the consequences of micronuclear envelope rupture. For complete details on the use and execution of this protocol, please refer to Mohr et al. (2021).


Asunto(s)
Citometría de Flujo/métodos , Pruebas de Micronúcleos/métodos , Animales , Línea Celular , Núcleo Celular/metabolismo , Células Cultivadas , Cromatina/metabolismo , Cromosomas/genética , Daño del ADN , Inestabilidad Genómica , Humanos , Espacio Intranuclear/fisiología , Micronúcleos con Defecto Cromosómico , Membrana Nuclear/metabolismo
4.
Genetics ; 217(1): 1-17, 2021 03 03.
Artículo en Inglés | MEDLINE | ID: mdl-33683371

RESUMEN

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.


Asunto(s)
Espacio Intranuclear/ultraestructura , Neuronas/ultraestructura , Animales , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Ciclo Celular , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Espacio Intranuclear/metabolismo , Neuroglía/ultraestructura
5.
Am J Hum Genet ; 108(2): 357-367, 2021 02 04.
Artículo en Inglés | MEDLINE | ID: mdl-33508234

RESUMEN

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.


Asunto(s)
Proteínas Portadoras/genética , Discapacidades del Desarrollo/genética , Epilepsia/genética , Glomeruloesclerosis Focal y Segmentaria/genética , Espacio Intranuclear/metabolismo , Síndrome Nefrótico/genética , Síndrome Nefrótico/metabolismo , Proteínas del Tejido Nervioso/genética , Adulto , Animales , Proteínas Portadoras/química , Proteínas Portadoras/metabolismo , Línea Celular , Niño , Preescolar , Codón sin Sentido , Discapacidades del Desarrollo/metabolismo , Epilepsia/metabolismo , Femenino , Glomeruloesclerosis Focal y Segmentaria/metabolismo , Humanos , Riñón/metabolismo , Masculino , Ratones , Mutación , Proteínas del Tejido Nervioso/química , Proteínas del Tejido Nervioso/metabolismo , Fenotipo , Podocitos/metabolismo , Secuenciación del Exoma
6.
Diagn Cytopathol ; 49(2): E65-E70, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32816379

RESUMEN

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.


Asunto(s)
Sarcoma de Células Dendríticas Foliculares/diagnóstico , Sarcoma de Células Dendríticas Foliculares/patología , Espacio Intranuclear/patología , Biopsia con Aguja Fina/métodos , Sarcoma de Células Dendríticas Foliculares/metabolismo , Humanos , Inmunohistoquímica/métodos , Masculino , Persona de Mediana Edad , FN-kappa B/metabolismo , Transducción de Señal/fisiología
7.
Int J Mol Sci ; 20(12)2019 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-31248120

RESUMEN

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.


Asunto(s)
Núcleo Celular/metabolismo , Metabolismo de los Lípidos , Fosfatidilinositoles/metabolismo , Animales , Fenómenos Químicos , Biología Computacional , Humanos , Espacio Intranuclear/metabolismo , Redes y Vías Metabólicas , Membrana Nuclear/metabolismo , Fosfatidilinositol 4,5-Difosfato/química , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fosfatidilinositoles/química , Transducción de Señal
8.
PLoS Pathog ; 15(2): e1007590, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30802273

RESUMEN

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.


Asunto(s)
Papillomaviridae/genética , Papillomaviridae/metabolismo , Proteína de la Leucemia Promielocítica/metabolismo , Antígenos Nucleares/metabolismo , Autoantígenos/metabolismo , Proteínas de la Cápside , Núcleo Celular , Genoma Viral , Humanos , Cuerpos de Inclusión Intranucleares , Espacio Intranuclear , Proteínas Nucleares , Papillomaviridae/patogenicidad , Proteína de la Leucemia Promielocítica/fisiología , Proteína SUMO-1/metabolismo , Factores de Transcripción , Proteínas Supresoras de Tumor , Replicación Viral
9.
J Cell Sci ; 132(5)2019 03 07.
Artículo en Inglés | MEDLINE | ID: mdl-30745340

RESUMEN

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.


Asunto(s)
Esclerosis Amiotrófica Lateral/genética , Proteína C9orf72/genética , Demencia Frontotemporal/genética , Neuronas Motoras/fisiología , Complejos Multiproteicos/metabolismo , Mutación/genética , ARN Nuclear/metabolismo , Esclerosis Amiotrófica Lateral/metabolismo , Animales , Proteína C9orf72/metabolismo , Células Cultivadas , Proteínas de Unión al ADN/metabolismo , Demencia Frontotemporal/metabolismo , Humanos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Espacio Intranuclear , Ratones , Factor de Empalme Asociado a PTB/metabolismo , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , ARN Nuclear/genética , Proteína FUS de Unión a ARN/metabolismo , Proteínas de Unión al ARN/metabolismo , Ratas
10.
PLoS One ; 13(12): e0209195, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30557374

RESUMEN

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.


Asunto(s)
Glucosa/deficiencia , Espacio Intranuclear/metabolismo , Proteínas Nucleares/metabolismo , Proteínas de Unión al ARN/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Expresión Génica , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Proteínas Nucleares/genética , Priones/metabolismo , Dominios Proteicos , Proteínas de Unión al ARN/genética , Saccharomyces cerevisiae , Proteínas de Saccharomyces cerevisiae/genética , Estrés Fisiológico/fisiología
11.
J Cell Biol ; 217(11): 3912-3929, 2018 11 05.
Artículo en Inglés | MEDLINE | ID: mdl-30194269

RESUMEN

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.


Asunto(s)
ARN Helicasas DEAD-box/metabolismo , Espacio Intranuclear/metabolismo , Poro Nuclear/metabolismo , Proteínas de Transporte Nucleocitoplasmático/metabolismo , ARN Mensajero/metabolismo , Proteínas de Unión al ARN/metabolismo , Transporte Activo de Núcleo Celular/fisiología , ARN Helicasas DEAD-box/genética , Células HeLa , Humanos , Poro Nuclear/genética , Proteínas de Transporte Nucleocitoplasmático/genética , ARN Mensajero/genética , Proteínas de Unión al ARN/genética
12.
Biochem Pharmacol ; 158: 141-152, 2018 12.
Artículo en Inglés | MEDLINE | ID: mdl-30096289

RESUMEN

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.


Asunto(s)
Sistemas de Liberación de Medicamentos/métodos , Inflamasomas/metabolismo , Espacio Intranuclear/metabolismo , Complicaciones Posoperatorias/tratamiento farmacológico , Complicaciones Posoperatorias/metabolismo , Factor de Transcripción ReIA/administración & dosificación , Abdomen/cirugía , Proteínas Adaptadoras Transductoras de Señales/antagonistas & inhibidores , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Proteínas Reguladoras de la Apoptosis/antagonistas & inhibidores , Proteínas Reguladoras de la Apoptosis/metabolismo , Inflamasomas/antagonistas & inhibidores , Intestinos/cirugía , Espacio Intranuclear/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos ICR , Complicaciones Posoperatorias/etiología
13.
J Mol Biol ; 430(23): 4711-4729, 2018 11 02.
Artículo en Inglés | MEDLINE | ID: mdl-29758260

RESUMEN

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.


Asunto(s)
Orgánulos/metabolismo , Proteínas/metabolismo , ARN/metabolismo , Animales , Citoplasma/metabolismo , Humanos , Espacio Intranuclear/metabolismo , Control de Calidad
14.
Sci Rep ; 8(1): 612, 2018 01 12.
Artículo en Inglés | MEDLINE | ID: mdl-29330450

RESUMEN

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.


Asunto(s)
Espacio Intranuclear/metabolismo , Proteínas Nucleares/metabolismo , Proteínas de Unión al ARN/química , Proteínas de Unión al ARN/metabolismo , Arginina/metabolismo , Sitios de Unión , Nucléolo Celular/metabolismo , Células HeLa , Humanos , Fosforilación , Unión Proteica , Dominios Proteicos , Transporte de Proteínas , Proteínas de Unión al ARN/genética , Serina/metabolismo
15.
Mutat Res ; 809: 99-107, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-28521962

RESUMEN

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.


Asunto(s)
Reparación del ADN , Inestabilidad Genómica , Espacio Intranuclear , Leucemia Promielocítica Aguda , Proteínas de Fusión Oncogénica/metabolismo , Proteína de la Leucemia Promielocítica/metabolismo , Animales , Apoptosis , Roturas del ADN de Doble Cadena , Humanos , Espacio Intranuclear/metabolismo , Espacio Intranuclear/patología , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/patología , Proteínas de Fusión Oncogénica/genética , Proteína de la Leucemia Promielocítica/genética , Homeostasis del Telómero
16.
Prensa méd. argent ; 103(8): 431-439, 20170000. tab
Artículo en Español | LILACS, BINACIS | ID: biblio-1372188

RESUMEN

Introducción: El núcleo y el citoplasma, como partes constituyentes de la célula se han medido desde el contexto de la geometría fractal, logrando hacer distinciones matemáticas más precisas entre células, así como todas sus posibles alteraciones. Objetivo: Caracterizar geométricamente las lesiones celulares mediante el espacio ocupado por el núcleo, medido a partir del método de Box Counting. Metodología: se evaluó el espacio ocupado por la superficie del Núcleo de 8 células normales, 8 ASCUS, 8 L-SIL y 8 H-SIL, y se establecieron diferencias a partir de los espacios ocupados por el núcleo. Se realizó una la validación clínica, mediante el cálculo de la sensibilidad, especificidad, negative likelihood ratio y el coeficiente Kappa respecto al Gold Standard. Resultados: los espacios ocupados por el núcleo, permitieron establecer diferencias histológicas y matemáticas más precisas evitando la indeterminación de las células ASCUS. Los resultados del diagnóstico matemático comparados con el convencional presentó sensibilidad y especificidad del 100%, negative likelihood ratio de cero, y un coeficiente Kappa de uno. Conclusiones: se logra caracterizar de forma exitosa el grado de lesión de las células de cuello uterino, a partir del espacio de ocupación del núcleo medido con el método de Box Counting.


Introduction: The nucleus and cytoplasm as constituent parts of the cell have been measured from the fractal geometry context, making more precise mathematical distinctions between cells, as well as all possible alterations. Objective: Geometrically characterize the cellular lesions by the space occupied by the nucleus, measured from the Box Counting method. Methodology: The space occupied by the nucleus of 8 normal cells, 8 ASCUS, 8 L-SIL and 8 H-SIL were evaluated, and differences were established from the spaces occupied by the nucleus. A clinical validation was performed by calculating the sensitivity, specificity, negative likelihood ratio and the Kappa coefficient with respect to Gold Standard. Results: The spaces occupied by the nucleus, allowed establishing more precise histological and mathematical differences avoiding the indetermination of ASCUS cells. The results of the mathematical diagnosis compared to the conventional one showed sensitivity and specificity of 100%, negative likelihood ratio of zero, and a Kappa coefficient of one. Conclusions: We successfully characterize the degree of lesion of the cervix cells, from the space of occupation of the nucleus measured with the method of Box Counting


Asunto(s)
Humanos , Femenino , Adulto , Estándares de Referencia , Núcleo Celular , Fractales , Espacio Intranuclear , Células Escamosas Atípicas del Cuello del Útero
17.
Nat Commun ; 7: 10291, 2016 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-26759081

RESUMEN

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.


Asunto(s)
Cromatina/metabolismo , Proteínas de Unión al ADN/metabolismo , Proteínas de Drosophila/metabolismo , Espacio Intranuclear/metabolismo , Complejo Represivo Polycomb 1/metabolismo , Secuencias de Aminoácidos , Animales , Línea Celular , Inmunoprecipitación de Cromatina , Drosophila , Técnica del Anticuerpo Fluorescente , Microscopía , Simulación de Dinámica Molecular , Imagen Óptica , Proteínas del Grupo Polycomb/metabolismo , Polímeros , Estructura Cuaternaria de Proteína , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Secuencia de ADN , Análisis de Secuencia de ARN
18.
Arch Kriminol ; 238(1-2): 57-63, 2016 Aug.
Artículo en Inglés, Alemán | MEDLINE | ID: mdl-29894604

RESUMEN

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.


Asunto(s)
Alcoholismo/patología , Hipotermia/patología , Espacio Intranuclear/patología , Cuerpos Cetónicos/análisis , Cetosis/patología , Lípidos/análisis , Vacuolas/patología , Causas de Muerte , Cetoacidosis Diabética/patología , Epitelio/patología , Humanos , Túbulos Renales Proximales/patología , Estudios Prospectivos
19.
Int J Mol Sci ; 16(12): 30343-61, 2015 Dec 19.
Artículo en Inglés | MEDLINE | ID: mdl-26703574

RESUMEN

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.


Asunto(s)
Transporte Activo de Núcleo Celular , Algoritmos , Espacio Intranuclear/metabolismo , Dipéptidos/metabolismo , Modelos Teóricos
20.
Eur. j. anat ; 19(4): 361-370, oct. 2015. ilus, tab, graf
Artículo en Inglés | IBECS | ID: ibc-145665

RESUMEN

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


Asunto(s)
Humanos , Próstata/ultraestructura , Neoplasias de la Próstata/patología , Neoplasia Intraepitelial Prostática/patología , Espacio Intranuclear/ultraestructura , Matriz Nuclear/ultraestructura , Estadísticas no Paramétricas , Tipificación Molecular
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