Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 24
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Brain Sci ; 14(1)2024 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-38248298

RESUMEN

This paper proposes the "calm contact" technique: an imaginative scenario where someone is in gentle contact with a loved one where the essence of the experience is to enjoy safety and calmness in peaceful social contact. The theoretical background is outlined by combining the brain mechanisms of stress reactions and hypnosis. In addition to the ancient stress responses (flight or fight or freeze), there are oxytocin-based options at the human level: tend and befriend behavior and the state of calm and connection, which is not a stress reaction but a resting reaction. These social-based reactions could prevent the organism from the primitive freezing response. Some studies proved that "hypnosis" as a setting reduces cortisol levels and could raise oxytocin levels. The beneficial mechanisms of the "calm contact" technique are analyzed in relation to "social support" and the psychoaffective effects of central oxytocin. The subjective effects of the proposed technique are outlined based on reports of healthy volunteers. The "calm contact" technique could be an alternative or adjunct to the "safe place" technique, applying the recent findings of endocrinological brain mechanisms of hypnosis. Clinical implications and limitations are briefly summarized.

2.
Front Psychiatry ; 14: 1168611, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37822796

RESUMEN

Background: Borderline personality disorder (BPD) is a severe mental disorder that affects attitudes toward the body. However, whether this condition also affects body schema and perceptual body image remains unclear. Previous questionnaire-based studies found dissatisfaction with one's body in patients with BPD. In addition to attitudinal body image, our study investigates whether body schema and perceptual body image are disturbed in patients with BPD. Method: Our study included 31 patients diagnosed with BPD (25 women) and 30 healthy individuals (19 women) (Mage = 29 for both groups). The SCID-5-PD interview was used to determine personality disorder. Attitudinal body image was measured using the Body Attitude Test (BAT) factors. Body schema and perceptual body image were measured by two conditions of a body representation task, the body portraying method (BPM). Results: BPD patients achieved higher scores in all three BAT factors and were more susceptible to misinformation in both conditions of BPM. Based on the results, BPD patients appear to have more negative attitudes toward their bodies and worse perceptual body image and body schema. Conclusion: The novel finding of our study is that, besides the previously found attitudinal dissatisfaction with the body, individuals with BPD also show disturbances at the levels of body schema and perceptual body image. Our findings concerning disturbances in body schema and perceptual body need further research into their etiological factors and provide new therapeutic targets for the treatment of BPD.

3.
PLoS One ; 17(7): e0266201, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35834562

RESUMEN

OBJECTIVES AND METHODS: In order to assess the internal consistency, fit indexes, test-retest reliability, and validity of the Personality Inventory for the DSM-5 (PID-5) and its associations with age, gender, and education, 471 non-clinical (69,6% female; mean age: 37,63) and 314 clinical participants (69,7% female, mean age: 37,41) were administered the Hungarian translation of the PID-5, as well as the SCL-90-R and the SCID-II Personality Questionnaire. RESULTS: We found that; (a) temporal consistency of the Hungarian PID-5 was confirmed by one-month test-retest reliability analysis, (b) validity of the PID-5 instrument is acceptable in the clinical and the non-clinical sample as well, based on significant correlations with SCID-II and SCL-90-R, (c) PID-5 facets' and domains' associations with gender, age, and level of education are in accordance with previous findings. CONCLUSION: These findings support that the Hungarian PID-5 is a reliable and valid instrument for both clinical and non-clinical populations.


Asunto(s)
Trastornos de la Personalidad , Personalidad , Manual Diagnóstico y Estadístico de los Trastornos Mentales , Femenino , Humanos , Hungría , Masculino , Trastornos de la Personalidad/diagnóstico , Inventario de Personalidad , Psicometría , Reproducibilidad de los Resultados
4.
Orv Hetil ; 160(38): 1495-1502, 2019 Sep.
Artículo en Húngaro | MEDLINE | ID: mdl-31537098

RESUMEN

A significant proportion of cancer patients reports a decline in their usual cognitive functions. This impairment may be the consequence of either the malignant disorder itself or the side-effect of the treatment. This impairment in cognitive skills was referred to with a sticky witty name as chemobrain or chemofog, reflecting on the old conception based on the assumption that solely the neurotoxic effect of chemotherapy was responsible for this kind of disturbances. However, today there is increasing evidence proving that such hypotheses can only partially explain the cognitive decline of cancer patients and cancer survivors. As a matter of fact, the cognitive impairment of cancer patients is a much more complex consequence of the malignant disorder than chemobrain or chemofog. Nowadays, this process is described as "cancer-related cognitive impairment" (CRCI). Orv Hetil. 2019; 160(38): 1495-1502.


Asunto(s)
Antineoplásicos/efectos adversos , Trastornos del Conocimiento/inducido químicamente , Disfunción Cognitiva/inducido químicamente , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Neoplasias/tratamiento farmacológico , Antineoplásicos/uso terapéutico , Cognición , Trastornos del Conocimiento/diagnóstico , Disfunción Cognitiva/diagnóstico , Humanos , Neoplasias/complicaciones
5.
J Pain Res ; 12: 1155-1178, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31114299

RESUMEN

Objectives: Pain catastrophizing is reliably associated with pain reports during experimental pain in healthy, pain-free subjects and in people with chronic pain. It also correlates with self-reports of clinical pain intensity/severity in a variety of disorders characterized by chronic pain in adults, adolescents and children. However, processes, through which it exerts its effects are yet unclear. In this paper, our primary aim was to synthesize neuroimaging research to open a window to possible mechanisms underlying pain catastrophizing in both chronic pain patients and healthy controls. We also aimed to compare whether the neural correlates of pain catastrophizing are similar in these two groups. Methods: PubMed and the Web of Science were searched for magnetic resonance imaging (MRI) studies that explored neural correlates of pain catastrophizing. Results: Twenty articles met the inclusion criteria. The results of our review show a connection between pain catastrophizing and brain areas tightly connected to pain perception (including the somatosensory cortices, anterior insula, anterior cingulate cortex and thalamus) and/or modulation (eg, the dorsolateral prefrontal cortex). Our results also highlight that these processes - in relation to pain catastrophizing - are more pronounced in chronic pain patients, suggesting that structural and functional brain alterations (and perhaps mechanisms) related to pain catastrophizing may depend on prior and/or relatively stable/constant pain experience. However, we also found methodological issues and differences that could lead to divergent results. Discussion: Based on our results, pain catastrophizing might be related to salience detection, pain processing, and top-down attentional processes. More research is recommended to explore neural changes to specific types of catastrophizing thoughts (eg, experimentally induced and/or state). Furthermore, we provide ideas regarding pain catastrophizing studies in the future for a more standardized approach.

6.
Nat Commun ; 10(1): 1288, 2019 03 20.
Artículo en Inglés | MEDLINE | ID: mdl-30894545

RESUMEN

The TFIIH subunit XPB is involved in combined Xeroderma Pigmentosum and Cockayne syndrome (XP-B/CS). Our analyses reveal that XPB interacts functionally with KAT2A, a histone acetyltransferase (HAT) that belongs to the hSAGA and hATAC complexes. XPB interacts with KAT2A-containing complexes on chromatin and an XP-B/CS mutation specifically elicits KAT2A-mediated large-scale chromatin decondensation. In XP-B/CS cells, the abnormal recruitment of TFIIH and KAT2A to chromatin causes inappropriate acetylation of histone H3K9, leading to aberrant formation of transcription initiation complexes on the promoters of several hundred genes and their subsequent overexpression. Significantly, this cascade of events is similarly sensitive to KAT2A HAT inhibition or to the rescue with wild-type XPB. In agreement, the XP-B/CS mutation increases KAT2A HAT activity in vitro. Our results unveil a tight connection between TFIIH and KAT2A that controls higher-order chromatin structure and gene expression and provide new insights into transcriptional misregulation in a cancer-prone DNA repair-deficient disorder.


Asunto(s)
Cromatina/química , Síndrome de Cockayne/genética , Histona Acetiltransferasas/genética , Histonas/metabolismo , Subunidades de Proteína/genética , Factor de Transcripción TFIIH/genética , Xerodermia Pigmentosa/genética , Acetilación , Proteína 9 Asociada a CRISPR/genética , Proteína 9 Asociada a CRISPR/metabolismo , Sistemas CRISPR-Cas , Línea Celular Tumoral , Cromatina/metabolismo , Síndrome de Cockayne/metabolismo , Síndrome de Cockayne/patología , Fibroblastos/citología , Fibroblastos/metabolismo , Edición Génica , Regulación de la Expresión Génica , Histona Acetiltransferasas/antagonistas & inhibidores , Histona Acetiltransferasas/metabolismo , Histonas/genética , Humanos , Modelos Biológicos , Osteoblastos/citología , Osteoblastos/metabolismo , Cultivo Primario de Células , Subunidades de Proteína/metabolismo , ARN Guía de Kinetoplastida/genética , ARN Guía de Kinetoplastida/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Transducción de Señal , Factor de Transcripción TFIIH/metabolismo , Iniciación de la Transcripción Genética , Xerodermia Pigmentosa/metabolismo , Xerodermia Pigmentosa/patología
7.
Sci Rep ; 9(1): 2753, 2019 02 26.
Artículo en Inglés | MEDLINE | ID: mdl-30808882

RESUMEN

Ultraviolet light induced pyrimidine dimer is a helix distortion DNA damage type, which recruits repair complexes. However, proteins of these complexes that take part in both DNA damage recognition and repair have been well-described, the regulation of the downstream steps of nucleotide excision repair (NER) have not been clearly clarified yet. In a high-throughput screen, we identified SerpinB2 (SPB2) as one of the most dramatically upregulated gene in keratinocytes following UV irradiation. We found that both the mRNA and the protein levels of SPB2 were increased upon UV irradiation in various cell lines. Additionally, UV damage induced translocation of SPB2 from the cytoplasm to the nucleus as well as the damage induced foci formation of it. Here we show that SPB2 co-localizes with XPB involved in the NER pathway at UV-induced repair foci. Finally, we demonstrated that UV irradiation promoted the association of SPB2 with ubiquitylated proteins. In basal cell carcinoma tumour cells, we identified changes in the subcellular localization of SPB2. Based on our results, we conclude that SPB2 protein has a novel role in UV-induced NER pathway, since it regulates the removal of the repair complex from the damaged site leading to cancerous malformation.


Asunto(s)
Daño del ADN , Reparación del ADN , Melanoma/patología , Osteosarcoma/patología , Inhibidor 2 de Activador Plasminogénico/metabolismo , Rayos Ultravioleta/efectos adversos , Neoplasias Óseas/etiología , Neoplasias Óseas/patología , Carcinoma Basocelular/etiología , Carcinoma Basocelular/patología , ADN Helicasas/genética , ADN Helicasas/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Humanos , Melanoma/etiología , Osteosarcoma/etiología , Inhibidor 2 de Activador Plasminogénico/genética , Dímeros de Pirimidina , Células Tumorales Cultivadas
8.
Mol Cell ; 65(3): 504-514.e4, 2017 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-28157507

RESUMEN

Transcription starts with the assembly of pre-initiation complexes on promoters followed by their opening. Current models suggest that class II gene transcription requires ATP and the TFIIH XPB subunit to open a promoter. Here, we observe that XPB depletion surprisingly leaves transcription virtually intact. In contrast, inhibition of XPB ATPase activity affects transcription, revealing that mRNA expression paradoxically accommodates the absence of XPB while being sensitive to the inhibition of its ATPase activity. The XPB-depleted TFIIH complex is recruited to active promoters and contributes to transcription. We finally demonstrate that the XPB ATPase activity is only used to relieve a transcription initiation block imposed by XPB itself. In the absence of this block, transcription initiation can take place without XPB ATPase activity. These results suggest that a helicase is dispensable for mRNA transcription, thereby unifying the mechanism of promoter DNA opening for the three eukaryotic RNA polymerases.


Asunto(s)
ADN Helicasas/genética , ADN Helicasas/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Transcripción Genética , Adenosina Trifosfatasas/metabolismo , Línea Celular , Perfilación de la Expresión Génica/métodos , Humanos , Mutación , Regiones Promotoras Genéticas , Análisis de Secuencia de ARN/métodos , Factor de Transcripción TFIIH/química , Factor de Transcripción TFIIH/metabolismo
9.
PLoS Genet ; 12(2): e1005791, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26845027

RESUMEN

DNA lesions are sensed by a network of proteins that trigger the DNA damage response (DDR), a signaling cascade that acts to delay cell cycle progression and initiate DNA repair. The Mediator of DNA damage Checkpoint protein 1 (MDC1) is essential for spreading of the DDR signaling on chromatin surrounding Double Strand Breaks (DSBs) by acting as a scaffold for PI3K kinases and for ubiquitin ligases. MDC1 also plays a role both in Non-Homologous End Joining (NHEJ) and Homologous Recombination (HR) repair pathways. Here we identify two novel binding partners of MDC1, the poly (ADP-ribose) Polymerases (PARPs) TNKS1 and 2. We find that TNKSs are recruited to DNA lesions by MDC1 and regulate DNA end resection and BRCA1A complex stabilization at lesions leading to efficient DSB repair by HR and proper checkpoint activation.


Asunto(s)
Roturas del ADN de Doble Cadena , Recombinación Homóloga , Tanquirasas/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteína BRCA1/genética , Proteína BRCA1/metabolismo , Sitios de Unión , Proteínas de Ciclo Celular , Línea Celular , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Humanos , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Recombinasa Rad51/genética , Recombinasa Rad51/metabolismo , Tanquirasas/genética , Transactivadores/genética , Transactivadores/metabolismo , Ubiquitina-Proteína Ligasas
10.
J Cell Biol ; 206(5): 589-98, 2014 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-25154395

RESUMEN

In nucleotide excision repair (NER), damage recognition by XPC-hHR23b is described as a critical step in the formation of the preincision complex (PInC) further composed of TFIIH, XPA, RPA, XPG, and ERCC1-XPF. To obtain new molecular insights into the assembly of the PInC, we analyzed its formation independently of DNA damage by using the lactose operator/repressor reporter system. We observed a sequential and ordered self-assembly of the PInC operating upon immobilization of individual NER factors on undamaged chromatin and mimicking that functioning on a bona fide NER substrate. We also revealed that the recruitment of the TFIIH subunit TTDA, involved in trichothiodystrophy group A disorder (TTD-A), was key in the completion of the PInC. TTDA recruits XPA through its first 15 amino acids, depleted in some TTD-A patients. More generally, these results show that proteins forming large nuclear complexes can be recruited sequentially on chromatin in the absence of their natural DNA target and with no reciprocity in their recruitment.


Asunto(s)
Cromatina/metabolismo , Línea Celular Tumoral , Daño del ADN , Reparación del ADN , Enzimas Reparadoras del ADN/metabolismo , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/metabolismo , Endonucleasas/metabolismo , Humanos , Proteínas Inmovilizadas/química , Proteínas Inmovilizadas/metabolismo , Proteínas Nucleares/metabolismo , Dominios y Motivos de Interacción de Proteínas , Multimerización de Proteína , Transporte de Proteínas , Factor de Transcripción TFIIH/metabolismo , Factores de Transcripción/metabolismo , Proteína de la Xerodermia Pigmentosa del Grupo A/química , Proteína de la Xerodermia Pigmentosa del Grupo A/metabolismo
12.
EMBO J ; 29(14): 2381-94, 2010 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-20562830

RESUMEN

All DNA-related processes rely on the degree of chromatin compaction. The highest level of chromatin condensation accompanies transition to mitosis, central for cell cycle progression. Covalent modifications of histones, mainly deacetylation, have been implicated in this transition, which also involves transcriptional repression. Here, we show that the Gcn5-containing histone acetyl transferase complex, Ada Two A containing (ATAC), controls mitotic progression through the regulation of the activity of non-histone targets. RNAi for the ATAC subunits Ada2a/Ada3 results in delayed M/G1 transition and pronounced cell division defects such as centrosome multiplication, defective spindle and midbody formation, generation of binucleated cells and hyperacetylation of histone H4K16 and alpha-tubulin. We show that ATAC localizes to the mitotic spindle and controls cell cycle progression through direct acetylation of Cyclin A/Cdk2. Our data describes a new pathway in which the ATAC complex controls Cyclin A/Cdk2 mitotic function: ATAC/Gcn5-mediated acetylation targets Cyclin A for degradation, which in turn regulates the SIRT2 deacetylase activity. Thus, we have uncovered an essential function for ATAC in regulating Cyclin A activity and consequent mitotic progression.


Asunto(s)
Acetiltransferasas/metabolismo , Mitosis/fisiología , Acetiltransferasas/genética , Secuencia de Aminoácidos , Animales , Ciclina A/metabolismo , Quinasa 2 Dependiente de la Ciclina/metabolismo , Células HeLa , Humanos , Ratones , Datos de Secuencia Molecular , Células 3T3 NIH , Interferencia de ARN , Huso Acromático/metabolismo , Tubulina (Proteína)/metabolismo , Factores de Transcripción p300-CBP/genética , Factores de Transcripción p300-CBP/metabolismo
13.
Cell Mol Life Sci ; 67(4): 611-28, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19936620

RESUMEN

Histone acetyl transferases (HATs) play a crucial role in eukaryotes by regulating chromatin architecture and locus-specific transcription. The GCN5 HAT was identified as a subunit of the SAGA (Spt-Ada-Gcn5-Acetyltransferase) multiprotein complex. Vertebrate cells express a second HAT, PCAF, that is 73% identical to GCN5. Here, we report the characterization of the mammalian ATAC (Ada-Two-A-Containing) complexes containing either GCN5 or PCAF in a mutually exclusive manner. In vitro ATAC complexes acetylate lysine 14 of histone H3. Moreover, ATAC- or SAGA-specific knock-down experiments suggest that both ATAC and SAGA are involved in the acetylation of histone H3K9 and K14 residues. Despite their catalytic similarities, SAGA and ATAC execute their coactivator functions on distinct sets of inducible target genes. Interestingly, ATAC strongly influences the global phosphorylation level of histone H3S10, suggesting that in mammalian cells a cross-talk exists linking ATAC function to H3S10 phosphorylation.


Asunto(s)
Regulación de la Expresión Génica , Histona Acetiltransferasas/metabolismo , Complejos Multienzimáticos/metabolismo , Factores de Transcripción p300-CBP/metabolismo , Acetilación , Animales , Catálisis , Drosophila , Técnicas de Silenciamiento del Gen , Células HeLa , Histona Acetiltransferasas/genética , Histonas/metabolismo , Humanos , Complejos Multienzimáticos/genética , Fosforilación , Factores de Transcripción p300-CBP/genética
14.
Trends Cell Biol ; 19(11): 617-29, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19819145

RESUMEN

Faithful repair of DNA damage is essential for the maintenance of genome integrity. Recent advances in the local induction of DNA damage and in cell biological imaging techniques have extended our understanding of DNA repair gained from biochemical and genetic approaches; these advances now reveal that the assembly of DNA repair complexes at sites of DNA damage is spatially and temporally regulated. Visualization of the dynamics of double strand breaks in living cells has also provided valuable insights into how chromosomal translocations form. Here we outline the most commonly used tools to induce and visualize the DNA repair process and we discuss the advantages and disadvantages inherent to each method.


Asunto(s)
Técnicas Citológicas , Reparación del ADN , ADN/genética , Técnicas Genéticas , Animales , ADN/metabolismo , Daño del ADN , Desoxirribonucleasas/metabolismo , Humanos , Translocación Genética
15.
Mol Cell Biol ; 29(6): 1649-60, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19114550

RESUMEN

One of the central questions in eukaryotic transcription is how activators can transmit their signal to stimulate gene expression in the context of chromatin. The multisubunit SAGA coactivator complex has both histone acetyltransferase and deubiquitination activities and remodels chromatin to allow transcription. Whether and how SAGA is able to regulate transcription at specific loci is poorly understood. Using mass spectrometry, immunoprecipitation, and Western blot analysis, we have identified human SPT20 (hSPT20) as the human homologue of the yeast Spt20 and show that hSPT20 is a bona fide subunit of the human SAGA (hSAGA; previously called TFTC/STAGA/PCAF) complex and that hSPT20 is required for the integrity of the hSAGA complex. We demonstrate that hSPT20 and other hSAGA subunits, together with RNA polymerase II, are specifically recruited to genes induced by endoplasmic reticulum (ER) stress. In good agreement with the recruitment of hSAGA to the ER stress-regulated genes, knockdown of hSTP20 hampers ER stress response. Surprisingly, hSPT20 recruitment was not observed for genes induced by another type of stress. These results provide evidence for a direct and specific role of the hSPT20-containing SAGA complex in transcriptional induction of ER stress-responsive genes. Thus, hSAGA regulates the transcription of stress-responsive genes in a stress type-dependent manner.


Asunto(s)
Retículo Endoplásmico/metabolismo , Factores de Transcripción/metabolismo , Factores de Transcripción p300-CBP/metabolismo , Acetilación , Secuencia de Aminoácidos , Regulación de la Expresión Génica , Células HeLa , Humanos , Datos de Secuencia Molecular , Subunidades de Proteína/genética , Subunidades de Proteína/metabolismo , ARN Polimerasa II/metabolismo , Factores de Transcripción/genética , Transcripción Genética , Factores de Transcripción p300-CBP/genética
16.
BMC Mol Biol ; 9: 57, 2008 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-18549481

RESUMEN

BACKGROUND: The tumour suppressor protein p53 is a sequence specific DNA-binding transcription regulator, which exerts its versatile roles in genome protection and apoptosis by affecting the expression of a large number of genes. In an attempt to obtain a better understanding of the mechanisms by which p53 transcription function is regulated, we studied p53 interactions. RESULTS: We identified BIP2 (Bric-à-brac interacting protein 2), the fly homolog of TAF3, a histone fold and a plant homeodomain containing subunit of TFIID, as an interacting partner of Drosophila melanogaster p53 (Dmp53). We detected physical interaction between the C terminus of Dmp53 and the central region of TAF3 both in yeast two hybrid assays and in vitro. Interestingly, DmTAF3 can also interact with human p53, and mammalian TAF3 can bind to both Dmp53 and human p53. This evolutionarily conserved interaction is functionally significant, since elevated TAF3 expression severely and selectively inhibits transcription activation by p53 in human cell lines, and it decreases the level of the p53 protein as well. CONCLUSION: We identified TAF3 as an evolutionarily conserved negative regulator of p53 transcription activation function.


Asunto(s)
Proteínas de Drosophila/metabolismo , Factor de Transcripción TFIID/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Animales , Western Blotting , Línea Celular , Línea Celular Tumoral , Proteínas de Drosophila/genética , Drosophila melanogaster , Células HeLa , Humanos , Inmunoprecipitación , Modelos Biológicos , Unión Proteica , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Spodoptera , Factores Asociados con la Proteína de Unión a TATA , Factor de Transcripción TFIID/genética , Transcripción Genética , Transfección , Proteína p53 Supresora de Tumor/genética , Técnicas del Sistema de Dos Híbridos
17.
J Mol Biol ; 375(2): 337-52, 2008 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-18022196

RESUMEN

Inverted repeats of insertion sequences (ISs) are indispensable for transposition. We demonstrate that sub-terminal sequences adjacent to the inverted repeats of IS30 are also required for optimal transposition activity. We have developed a cell-free recombination system and showed that the transposase catalyses formation of a figure-of-eight transposition intermediate, where a 2 bp long single strand bridge holds the inverted repeat sequences (IRs) together. This is the first demonstration of the figure-of-eight structure in a non-IS3 family element, suggesting that this mechanism is likely more widely adopted among IS families. We show that the absence of sub-terminal IS30 sequences negatively influences figure-of-eight production both in vivo and in vitro. These regions enhance IR-IR junction formation and IR-targeting events in vivo. Enhancer elements have been identified within 51 bp internal to IRL and 17 bp internal to IRR. In the right end, a decanucleotide, 5'-GAGATAATTG-3', is responsible for wild-type activity, while in the left end, a complex assembly of repetitive elements is required. Functioning of the 10 bp element in the right end is position-dependent and the repetitive elements in the left end act cooperatively and may influence bendability of the end. In vitro kinetic experiments suggest that the sub-terminal enhancers may, at least partly, be transposase-dependent. Such enhancers may reflect a subtle regulatory mechanism for IS30 transposition.


Asunto(s)
Elementos Transponibles de ADN , Secuencias Repetidas Terminales , Transposasas/metabolismo , Secuencia de Bases , Sitios de Unión , Sistema Libre de Células , Análisis Mutacional de ADN , Cartilla de ADN , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Bacteriano/aislamiento & purificación , ADN Circular/genética , Dimerización , Electroforesis en Gel de Poliacrilamida , Elementos de Facilitación Genéticos , Escherichia coli/genética , Genes Bacterianos , Técnicas In Vitro , Cinética , Modelos Genéticos , Modelos Moleculares , Datos de Secuencia Molecular , Mutagénesis Insercional , Conformación de Ácido Nucleico , Sistemas de Lectura Abierta , Plásmidos , Mutación Puntual , Reacción en Cadena de la Polimerasa , Recombinación Genética , Salmonella typhimurium/genética , Transposasas/química , Transposasas/genética , Transposasas/aislamiento & purificación
18.
Mol Microbiol ; 63(6): 1731-47, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17367392

RESUMEN

We have analysed the transposition and target selection strategy of IS1655, a typical IS30 family member resident in Neisseria meningitidis. We have redefined IS1655 as a 1080 bp long element with 25 bp imperfect inverted repeats (IRs), which generates a 3 bp target duplication and have shown that it transposes using an intermediate with abutted IRs separated by 2 bp. IS1655 exhibits bipartite target specificity inserting preferentially either next to sequences similar to its IRs or into an unrelated but well defined sequence. IR-targeting leads to the formation of a new junction in which the targeted IR and one of the donor IRs are separated by 2 bp. The non-IR targets were characterized as an imperfect 19 bp palindrome in which the central five positions show slight GC excess and the distal region is AT-rich. Artificial targets designed according to the consensus were recognized by the element as hot spots for insertion. The organization of IS1655 is similar to that of other IS30 family members. Moreover, it shows striking similarity to IS30 in transposition strategy even though their transposases differ in their N-terminal regions, which, for IS30, appears to determine target specificity. Comparative analysis of the transposases and the evolutionary aspects of sequence variants are also briefly discussed.


Asunto(s)
Elementos Transponibles de ADN/fisiología , Neisseria meningitidis/genética , Transposasas/metabolismo , ADN Bacteriano/química , Genoma Bacteriano , Datos de Secuencia Molecular , Mutagénesis Insercional
19.
PLoS One ; 2(3): e316, 2007 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-17375202

RESUMEN

TFIID plays a role in nucleating RNA polymerase II preinitiation complex assembly on protein-coding genes. TFIID is a multisubunit complex comprised of the TATA box binding protein (TBP) and 14 TBP-associated factors (TAFs). Another class of multiprotein transcriptional regulatory complexes having histone acetyl transferase (HAT) activity, and containing TAFs, includes TFTC, STAGA and the PCAF/GCN5 complex. Looking for as yet undiscovered subunits by a proteomic approach, we had identified TAF8 and SPT7L in human TFTC preparations. Subsequently, however, we demonstrated that TAF8 was not a stable component of TFTC, but that it is present in a small TAF complex (SMAT), containing TAF8, TAF10 and SPT7L, that co-purified with TFTC. Thus, TAF8 is a subunit of both TFIID and SMAT. The latter has to be involved in a pathway of complex formation distinct from the other known TAF complexes, since these three histone fold (HF)-containing proteins (TAF8, TAF10 and SPT7L) can never be found together either in TFIID or in STAGA/TFTC HAT complexes. Here we show that TAF8 is absolutely necessary for the integration of TAF10 in a higher order TFIID core complex containing seven TAFs. TAF8 forms a heterodimer with TAF10 through its HF and proline rich domains, and also interacts with SPT7L through its C-terminal region, and the three proteins form a complex in vitro and in vivo. Thus, the TAF8-TAF10 and TAF10-SPT7L HF pairs, and also the SMAT complex, seem to be important regulators of the composition of different TFIID and/or STAGA/TFTC complexes in the nucleus and consequently may play a role in gene regulation.


Asunto(s)
Proteínas Similares a la Proteína de Unión a TATA-Box/genética , Factores Asociados con la Proteína de Unión a TATA/genética , Secuencia de Aminoácidos , Animales , Western Blotting , ADN Complementario/genética , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Amplificación de Genes , Humanos , Ratones , Reacción en Cadena de la Polimerasa/métodos , Subunidades de Proteína/química , Proteínas Similares a la Proteína de Unión a TATA-Box/química , Proteínas Similares a la Proteína de Unión a TATA-Box/metabolismo , Factores Asociados con la Proteína de Unión a TATA/química , Factores de Transcripción/química , Factores de Transcripción/genética , Transfección , Levaduras/genética
20.
Mol Cell Biol ; 26(2): 402-12, 2006 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-16382133

RESUMEN

Transactivation-transformation domain-associated protein (TRRAP) is a component of several multiprotein histone acetyltransferase (HAT) complexes implicated in transcriptional regulation. TRRAP was shown to be required for the mitotic checkpoint and normal cell cycle progression. MRE11, RAD50, and NBS1 (product of the Nijmegan breakage syndrome gene) form the MRN complex that is involved in the detection, signaling, and repair of DNA double-strand breaks (DSBs). By using double immunopurification, mass spectrometry, and gel filtration, we describe the stable association of TRRAP with the MRN complex. The TRRAP-MRN complex is not associated with any detectable HAT activity, while the isolated other TRRAP complexes, containing either GCN5 or TIP60, are. TRRAP-depleted extracts show a reduced nonhomologous DNA end-joining activity in vitro. Importantly, small interfering RNA knockdown of TRRAP in HeLa cells or TRRAP knockout in mouse embryonic stem cells inhibit the DSB end-joining efficiency and the precise nonhomologous end-joining process, further suggesting a functional involvement of TRRAP in the DSB repair processes. Thus, TRRAP may function as a molecular link between DSB signaling, repair, and chromatin remodeling.


Asunto(s)
Proteínas de Ciclo Celular/metabolismo , Daño del ADN , Enzimas Reparadoras del ADN/metabolismo , Reparación del ADN , Proteínas de Unión al ADN/metabolismo , Proteínas Nucleares/metabolismo , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Ácido Anhídrido Hidrolasas , Proteínas Adaptadoras Transductoras de Señales , Animales , Proteínas de Ciclo Celular/genética , Línea Celular Tumoral , Ensamble y Desensamble de Cromatina , Cromatografía en Gel , Enzimas Reparadoras del ADN/genética , Proteínas de Unión al ADN/genética , Histona Acetiltransferasas/genética , Histona Acetiltransferasas/metabolismo , Humanos , Lisina Acetiltransferasa 5 , Proteína Homóloga de MRE11 , Ratones , Proteínas Nucleares/genética , Unión Proteica , ARN Interferente Pequeño/genética , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Transcripción Genética , Factores de Transcripción p300-CBP
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...