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1.
Climacteric ; 24(3): 229-235, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33527841

RESUMO

In clinical practice, micronized progesterone (MP) is frequently recommended to treat signs and symptoms of skin and hair aging in menopausal women. The aim of this comprehensive review was to evaluate whether topically or systemically applied MP may effectively prevent or slow down signs of skin and hair aging. Three out of six identified studies reported an impact of MP on skin aging markers in menopausal women. Of these, two studies reported a benefit: one for topically applied MP, another for systemically applied combined menopausal hormone therapy (MHT) comprising MP as progestogen for endometrial protection. Tolerability and safety of MP were good. However, there was no study investigating the impact of MP on menopausal scalp hair. In conclusion, delay of skin aging comprises lifestyle adjustment, antioxidants, and several esthetic procedures. In menopausal women, MHT displays beneficial effects on skin aging. There is poor quality but promising scientific evidence for MP displaying anti-aging skin effects in menopausal women. However, good quality studies are needed.


Assuntos
Terapia de Reposição de Estrogênios , Cabelo/efeitos dos fármacos , Menopausa/efeitos dos fármacos , Progesterona/administração & dosagem , Envelhecimento da Pele/efeitos dos fármacos , Administração Oral , Administração Tópica , Feminino , Humanos , Pessoa de Meia-Idade
2.
Neuroimage Clin ; 24: 102010, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31734532

RESUMO

The dynamic connectome perspective states that brain functions arise from the functional integration of distributed and/or partly overlapping networks. Diffuse low-grade gliomas (DLGG) have a slow infiltrating character. Here we addressed whether and how anatomical disconnection following DLGG growth and resection might interfere with functional resting-state connectivity, specifically in relation to picture naming. Thirty-nine native French persons with a left DLGG were included. All underwent awake surgical resection of the tumor using direct brain electrostimulation to preserve critical eloquent regions. The anatomical disconnectivity risk following the DLGG volume and the resection, and the functional connectivity of resting-state fMRI images in relation to picture naming were evaluated prior to and three months after surgery. Resting-state connectivity patterns were compared with nineteen healthy controls. It was demonstrated that picture naming was strongly dependent on the semantic network that emerged from the integration and interaction of regions within multiple resting-state brain networks, in which their specific role could be explained in the light of the broader resting-state network they take part in. It emphasized the importance of a whole brain approach with specific clinical data input, during resting-state analysis in case of lesion. Adaptive plasticity was found in secondary regions, functionally connected to regions close to the tumor and/or cavity, marked by an increased connectivity of the right and left inferior parietal lobule with the left inferior temporal gyrus. In addition, an important role was identified for the superior parietal lobe, connected with the frontal operculum, suggesting functional compensation by means of attentional resources in order to name a picture via recruitment of the frontoparietal attention network.


Assuntos
Neoplasias Encefálicas , Córtex Cerebral/fisiopatologia , Conectoma , Glioma , Rede Nervosa/fisiopatologia , Plasticidade Neuronal/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Adulto , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/cirurgia , Córtex Cerebral/diagnóstico por imagem , Feminino , Glioma/diagnóstico por imagem , Glioma/patologia , Glioma/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Rede Nervosa/diagnóstico por imagem , Procedimentos Neurocirúrgicos
3.
BMC Cardiovasc Disord ; 18(1): 41, 2018 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-29486707

RESUMO

BACKGROUND: Myxomatous mitral valve prolapse is a common cardiac abnormality. Morbus Barlow is characterized by excess myxomatous leaflet tissue, bileaflet prolapse or billowing, chordae elongation and annular dilatation with or without calcification. Extensive myxoid degeneration with destruction of the normal three-layered leaflet tissue architecture is observed histologically in such patients. Autosomal dominant inheritance with an age and sex-dependent expression has long been recognised. This review explores the current understanding of the genetics of bileaflet prolapse, with a focus on genetic analysis and the role for echocardiographical screening of the first degree relatives of affected patients. METHODS: Systematic literature searches were performed using PubMed and Embase up to September 2017. In Disse et al.'s study (study one) first degree relatives of 25 patients with Morbus Barlow who underwent mitral valve repair were screened for bileaflet valve prolapse. In Nesta et al.'s study one family with three living generations of 43 individuals with 9 confirmed cases of MVP was screened. Genotyping was performed in four families for 344 microsatellite markers from Chromosome 1 to 16. RESULTS: In study one, autosomal dominant inheritance was shown in four pedigrees. Genome-wide linkage analysis of the most informative pedigree (24 individuals, three generations) showed a significant linkage for markers mapping to chromosome 16p. Linkage to this locus was confirmed in a second family within the same study, but was excluded in the remaining two pedigrees. In study two an autosomal dominant locus was mapped to chromosome 13. 8 of the 9 individuals affected were found to suffer from bileaflet prolapse. CONCLUSIONS: Barlow's disease is a heritable trait but the genetic causes remain largely elusive. Ch16p11.2-p12.1 is the only locus proven to be associated with bileaflet prolapse. Locus 13.q31.3-q32.1 was shown to cause bileaflet as well as posterior leaflet prolapse. This review intends to make physicians aware of genetic causes of myxomatous mitral valve prolapse, thereby emphasising the importance of cardiological examination of first-degree relatives of patients with Morbus Barlow. Integrated and more comprehensive studies are needed for identification of genes involved in this heterogenic disease. Further genomic studies may facilitate more individualised and accurate risk assessment and may help to develop possible preventive stategies for patients in the future.


Assuntos
Prolapso da Valva Mitral/genética , Valva Mitral/anormalidades , Adulto , Ecocardiografia , Feminino , Marcadores Genéticos , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Hereditariedade , Humanos , Masculino , Pessoa de Meia-Idade , Valva Mitral/diagnóstico por imagem , Valva Mitral/fisiopatologia , Prolapso da Valva Mitral/diagnóstico por imagem , Prolapso da Valva Mitral/fisiopatologia , Linhagem , Prognóstico , Fatores de Risco
4.
Neurochirurgie ; 63(3): 135-141, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28506481

RESUMO

Neuropsychological care of patients suffering from an infiltrative glioma and candidates for a neurosurgery under awake condition with intraoperative functional mapping is a critical and mandatory stage in therapeutic management. It enables to estimate the functional impact of the tumor and, consequently, the efficacy of functional reorganization typically observed in these patients, not only to better predict surgery outcomes and select appropriate tasks for intraoperative functional mapping, but also to plan efficient and individualized postoperative cognitive rehabilitation strategies. Neuropsychological care management also enables patients to benefit from a solid psychological preparation both to the surgery and its associated transitory functional consequences, as well as provide a personalized psychological and emotional long-term support. Based on their solid experience in the peri-operative care of diffuse low-grade glioma patients, the authors thoroughly describe the different stages of neuropsychological management. Cognitive, emotional and language assessments typically used by the authors around and during surgery are reported, and different possible avenues of improvement are further discussed.


Assuntos
Mapeamento Encefálico , Neoplasias Encefálicas/fisiopatologia , Cognição , Glioma/fisiopatologia , Monitorização Neurofisiológica Intraoperatória , Idioma , Monitorização Intraoperatória , Encéfalo/cirurgia , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/cirurgia , Cognição/fisiologia , Glioma/diagnóstico , Glioma/patologia , Glioma/cirurgia , Humanos , Monitorização Intraoperatória/métodos , Procedimentos Neurocirúrgicos/métodos , Vigília/fisiologia
5.
Neurochirurgie ; 63(3): 250-258, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28161011

RESUMO

OBJECTIVE: Incidentally discovered diffuse low-grade gliomas progress in a fashion similar to their symptomatic counterparts. Their early detection allows more effective pre-emptive and individualized oncological treatment. We assessed the safety and efficacy of maximal safe resection according to functional boundaries for incidental diffuse low-grade gliomas in eloquent areas. MATERIAL AND METHODS: Two-centre retrospective series of adult patients with incidental diffuse low-grade gliomas located within/close to eloquent areas in the dominant hemisphere, treated with maximal surgical resection according to functional boundaries under intraoperative functional cortico-subcortical monitoring under awake conditions, and with a minimal follow-up of 24months. RESULTS: The series included 19 patients (8 men, 11 women) with no preoperative neurological deficit but with a radiologically enlarged glioma. No intraoperative seizure, postoperative infection, haematoma or wound-healing problem was observed. In the immediate postsurgical period, a transient neurological worsening occurred in 10 patients. The resection (mean rate 96.4%; range, 82.4-100) was supratotal in 5 cases, total in 5 cases, subtotal in 7 cases, and partial in 2 cases. Six months after surgery, all patients recovered after functional rehabilitation, with no permanent neurological deficit, Karnofsky Performance Status was 100 (except for one patient who received early postoperative radiotherapy) and no seizures were observed. The survival without progression requiring oncological treatment was significantly longer in patients with a total/supratotal resection than in patients with a partial/subtotal resection. CONCLUSIONS: These results suggest the reproducibility, safety, and effectiveness of an early maximal functionally based resection within cortico-subcortical functional boundaries for incidental diffuse low-grade gliomas in adults in centres hyperspecialized in surgical neuro-oncology.


Assuntos
Neoplasias Encefálicas/cirurgia , Epilepsia/cirurgia , Glioma/cirurgia , Adulto , Encéfalo/cirurgia , Mapeamento Encefálico/métodos , Neoplasias Encefálicas/complicações , Neoplasias Encefálicas/diagnóstico , Estimulação Elétrica/métodos , Epilepsia/etiologia , Feminino , Glioma/complicações , Glioma/diagnóstico , Humanos , Monitorização Neurofisiológica Intraoperatória , Masculino , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos/métodos , Complicações Pós-Operatórias/prevenção & controle , Estudos Retrospectivos , Resultado do Tratamento , Vigília/fisiologia
6.
Oncogene ; 36(7): 933-941, 2017 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-27477692

RESUMO

Tumor surveillance of natural killer (NK) cells is mediated by the cytotoxicity receptor natural-killer group 2 member D (NKG2D). Ligands for NKG2D are generally not expressed on healthy cells, but induced on the surface of malignant cells. To date, NKG2D ligand (NKG2D-L) induction was mainly described to depend on the activation of the DNA damage response, although the molecular mechanisms that regulate NKG2D-L expression remain largely unknown. Here, we show that the acetyltransferases CBP (CREB-binding protein) and p300 play a crucial role in the regulation of NKG2D-L on tumor cells. Loss of CBP/p300 decreased the basal cell surface expression of human ligands and reduced the upregulation of MICA/B and ULBP2 in response to histone deacetylase inhibitors or DNA damage. Furthermore, CBP/P300 deficiency abrogated the sensitivity of stressed cells to NK cell-mediated killing. CBP/p300 were also identified as major regulators of mouse NKG2D ligand RAE-1 in vitro and in vivo using the Eµ-Myc lymphoma model. Mechanistically, we observed an enhanced activation of the CBP/p300 binding transcription factor CREB (cAMP response element-binding protein) correlating to the NKG2D-L upregulation. Moreover, increased binding of CREB and CBP/p300 to NKG2D-L promoters and elevated histone acetylation were detectable. This study provides strong evidence for a major role of CBP and p300 in orchestrating NKG2D-L induction and consequently immunosurveillance of tumors in mice and humans. These findings might help to develop novel immunotherapeutic approaches against cancer.


Assuntos
Antígenos de Histocompatibilidade Classe I/genética , Peptídeos e Proteínas de Sinalização Intercelular/genética , Linfoma/metabolismo , Subfamília K de Receptores Semelhantes a Lectina de Células NK/metabolismo , Proteínas Associadas à Matriz Nuclear/genética , Proteínas de Transporte Nucleocitoplasmático/genética , Fatores de Transcrição de p300-CBP/metabolismo , Acetilação , Animais , Células Cultivadas , Modelos Animais de Doenças , Proteínas Ligadas por GPI/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Linfoma/genética , Linfoma/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Subfamília K de Receptores Semelhantes a Lectina de Células NK/genética , Transcrição Gênica , Fatores de Transcrição de p300-CBP/genética
7.
Am J Transplant ; 16(12): 3322-3337, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27529775

RESUMO

The pathophysiological importance of the immunogenicity of damage-associated molecular patterns (DAMPs) has been pinpointed by their identification as triggers of allograft rejection following release from dying cells, such as after ischemia-reperfusion injury. In cancers, however, this strong trigger of a specific immune response gives rise to the success of cancer immunotherapy. Here, we review the recently literature on the pathophysiological importance of DAMP release and discuss the implications of these processes for allograft rejection and cancer immunotherapy, revealing a striking mechanistic overlap. We conclude that these two fields share a common mechanistic basis of regulated necrosis and inflammation, the molecular characterization of which may be helpful for both oncologists and the transplant community.


Assuntos
Rejeição de Enxerto/imunologia , Inflamação/fisiopatologia , Neoplasias/imunologia , Traumatismo por Reperfusão/imunologia , Aloenxertos , Animais , Rejeição de Enxerto/patologia , Humanos , Necrose , Neoplasias/patologia , Traumatismo por Reperfusão/patologia
8.
Am J Transplant ; 16(12): 3338-3361, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27421829

RESUMO

Upon solid organ transplantation and during cancer immunotherapy, cellular stress responses result in the release of damage-associated molecular patterns (DAMPs). The various cellular stresses have been characterized in detail over the last decades, but a unifying classification based on clinically important aspects is lacking. Here, we provide an in-depth review of the most recent literature along with a unifying concept of the danger/injury model, suggest a classification of DAMPs, and review the recently elaborated mechanisms that result in the emission of such factors. We further point out the differences in DAMP responses including the release following a heat shock pattern, endoplasmic reticulum stress, DNA damage-mediated DAMP release, and discuss the diverse pathways of regulated necrosis in this respect. The understanding of various forms of DAMPs and the consequences of their different release patterns are prerequisite to associate serum markers of cellular stresses with clinical outcomes.


Assuntos
Estresse do Retículo Endoplasmático , Rejeição de Enxerto/etiologia , Inflamação/fisiopatologia , Transplante de Órgãos/efeitos adversos , Animais , Humanos , Necrose
9.
Nature ; 414(6865): 768-73, 2001 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-11742404

RESUMO

Overexpression of the proto-oncogene c-myc has been implicated in the genesis of diverse human tumours. c-Myc seems to regulate diverse biological processes, but its role in tumorigenesis and normal physiology remains enigmatic. Here we report the generation of an allelic series of mice in which c-myc expression is incrementally reduced to zero. Fibroblasts from these mice show reduced proliferation and after complete loss of c-Myc function they exit the cell cycle. We show that Myc activity is not needed for cellular growth but does determine the percentage of activated T cells that re-enter the cell cycle. In vivo, reduction of c-Myc levels results in reduced body mass owing to multiorgan hypoplasia, in contrast to Drosophila c-myc mutants, which are smaller as a result of hypotrophy. We find that c-myc substitutes for c-myc in fibroblasts, indicating they have similar biological activities. This suggests there may be fundamental differences in the mechanisms by which mammals and insects control body size. We propose that in mammals c-Myc controls the decision to divide or not to divide and thereby functions as a crucial mediator of signals that determine organ and body size.


Assuntos
Genes cdc , Genes myc/fisiologia , Linfócitos T/citologia , Animais , Constituição Corporal/genética , Contagem de Células , Ciclo Celular/fisiologia , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/fisiologia , Divisão Celular/fisiologia , Tamanho Celular , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p27 , Drosophila , Embrião de Mamíferos/citologia , Embrião não Mamífero , Fibroblastos , Marcação de Genes , Camundongos , Proto-Oncogene Mas , Especificidade da Espécie , Linfócitos T/imunologia , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/fisiologia
10.
Science ; 294(5549): 2181-6, 2001 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-11739961

RESUMO

Little is known about the dynamics of chromosomes in interphase nuclei. By tagging four chromosomal regions with a green fluorescent protein fusion to lac repressor, we monitored the movement and subnuclear position of specific sites in the yeast genome, sampling at short time intervals. We found that early and late origins of replication are highly mobile in G1 phase, frequently moving at or faster than 0.5 micrometers/10 seconds, in an energy-dependent fashion. The rapid diffusive movement of chromatin detected in G1 becomes constrained in S phase through a mechanism dependent on active DNA replication. In contrast, telomeres and centromeres provide replication-independent constraint on chromatin movement in both G1 and S phases.


Assuntos
Cromatina/fisiologia , Cromossomos Fúngicos/fisiologia , Interfase , Saccharomyces cerevisiae/fisiologia , Trifosfato de Adenosina/metabolismo , Núcleo Celular/fisiologia , Centrômero/fisiologia , Replicação do DNA , DNA Fúngico/biossíntese , Fase G1 , Proteínas de Fluorescência Verde , Proteínas Luminescentes , Filmes Cinematográficos , Mutação , Membrana Nuclear/fisiologia , Origem de Replicação , Fase S , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Telômero/fisiologia
11.
Biochemistry ; 40(6): 1624-34, 2001 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-11327821

RESUMO

Epipodophyllotoxins are effective anti-tumor drugs that inhibit eukaryotic DNA topoisomerase II by trapping the enzyme in a covalent complex with DNA. We show that both the recombinant N-terminal ATPase domain and the B'A' core domain of human topoisomerase IIalpha (htopoIIalpha) bind radiolabeled etoposide specifically, even in the absence of DNA. The addition of ATP impairs etoposide binding to the holoenzyme and the N-terminal domain, but not to the core domain. To see if this interference resembles that between novobiocin and ATP in the bacterial GyrB subunit, we modeled the structure of the N-terminal domain of htopoIIalpha and performed molecular docking analysis with etoposide. Mutagenesis of critical amino acids, predicted to stabilize the drug within the N-terminal domain, reveals a less efficient binding of etoposide to the mutated proteins as monitored by direct drug binding assays, although the binding of ATP is not affected.


Assuntos
Antineoplásicos Fitogênicos/metabolismo , DNA Topoisomerases Tipo II , DNA Topoisomerases Tipo II/metabolismo , DNA/metabolismo , Etoposídeo/metabolismo , Isoenzimas/metabolismo , Fragmentos de Peptídeos/metabolismo , Trifosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Antígenos de Neoplasias , Ligação Competitiva/genética , DNA Girase , DNA Topoisomerases Tipo II/genética , Proteínas de Ligação a DNA , Humanos , Isoenzimas/antagonistas & inibidores , Isoenzimas/genética , Modelos Químicos , Modelos Moleculares , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Fragmentos de Peptídeos/genética , Ligação Proteica/genética , Estrutura Terciária de Proteína/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Inibidores da Topoisomerase II
12.
Int J Cancer ; 88(1): 99-107, 2000 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-10962446

RESUMO

Cellular resistance to etoposide has been correlated both with reduced levels and an aberrant cytoplasmic accumulation of the drug's target, topoisomerase IIalpha (topo IIalpha). It is not known, however, whether a cytoplasmic pool of topo IIalpha is sufficient to confer drug resistance on cultured mammalian cells. In our study, we have transfected mouse fibroblasts and human 293 cells with truncated forms of human topo IIalpha fused to GFP and have examined the transformants for the subcellular localization of topo IIalpha and their resistance to etoposide. Transient transfection resulted in high-level expression of all GFP-topo IIalpha fusions tested, whereas in stably transfected cells the levels varied significantly. Transfectants expressing a central or a carboxy-terminal topo IIalpha domain (aa 428-1504, 639-1028 or 1028-1504) accumulated high levels of the fusion proteins, while only very low amounts of GFP-topo IIalpha proteins were observed in cell lines expressing constructs that retain the amino-terminus of the enzyme (aa 1-1214, aa 1-939, aa 1-611). Our results suggest that the topo IIalpha amino-terminus affects the stability of truncated forms of the enzyme in mammalian cells, perhaps due to targeted degradation. Assays that screen for cell vitality and DNA synthesis reveal no significant changes in etoposide sensitivity in transfected cells expressing high levels of cytoplasmic or nuclear localized topo II fusion proteins. Retroviral expression of a cytoplasmically anchored domain of human topo IIalpha also failed to confer drug resistance. These results suggest that a cytoplasmic pool of topo IIalpha is not sufficient to render cultured mammalian cells drug resistant.


Assuntos
DNA Topoisomerases Tipo II , DNA Topoisomerases Tipo II/biossíntese , Etoposídeo/farmacologia , Isoenzimas/biossíntese , Células 3T3/efeitos dos fármacos , Células 3T3/enzimologia , Animais , Antígenos de Neoplasias , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , DNA Topoisomerases Tipo II/genética , Proteínas de Ligação a DNA , Resistência a Medicamentos , Proteínas de Fluorescência Verde , Humanos , Isoenzimas/genética , Rim/citologia , Rim/efeitos dos fármacos , Rim/enzimologia , Proteínas Luminescentes/biossíntese , Proteínas Luminescentes/genética , Camundongos , Microscopia de Fluorescência , Fragmentos de Peptídeos/biossíntese , Fragmentos de Peptídeos/genética , Estrutura Terciária de Proteína , Ratos , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/genética , Transfecção
13.
J Cell Sci ; 113 ( Pt 15): 2641-6, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10893179

RESUMO

The eukaryotic homologues of the Escherichia coli RecQ DNA helicase play conserved roles in the maintenance of genome stability. Results obtained in yeast and mammalian systems are beginning to form a coherent picture about what these helicases do to ensure normal cell division and why humans who lack these enzymes are cancer prone. Recent data suggest that the yeast enzyme Sgs1p, as well as two human homologues, which are encoded by the Bloom's and Werner's syndrome genes, function during DNA replication and possibly in a replication checkpoint specific to S phase.


Assuntos
Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , DNA Helicases/genética , DNA Helicases/metabolismo , Replicação do DNA/fisiologia , Células Eucarióticas/citologia , Animais , Divisão Celular/fisiologia , Células Eucarióticas/enzimologia , Humanos , RecQ Helicases
15.
Exp Cell Res ; 249(2): 308-19, 1999 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-10366430

RESUMO

DNA topoisomerase II (topo II) is the target of many anticancer drugs and is often altered in drug-resistant cell lines. In some tumor cell lines truncated isoforms of topo IIalpha are localized to the cytoplasm. To study the localization and function of individual enzyme domains, we have epitope-tagged several fragments of human topo IIalpha and expressed them by retroviral infection of rodent and human cells. We find that fusion of the topo II fragments to the hydrophobic tail of human liver cytochrome b5 anchors the fusion protein to the outer face of cytoplasmic membranes, as determined by colocalization with calnexin and selective detergent permeabilization. Moreover, whereas the minimal ATPase domain (aa 1-266) is weakly and diffusely expressed, addition of the cytb5 anchor (1-266-b5) increases its steady-state level 16-fold with no apparent toxicity. Similar results are obtained with the complete ATPase domain (aa 1-426). A C-terminal domain (aa 1030-1504) of human topo IIalpha containing an intact dimerization motif is stably expressed and accumulates in the nucleus. Fusion to the cytb5 anchor counteracts the nuclear localization signal and relocalizes the protein to cytoplasmic membranes. In conclusion, we describe a technique that stabilizes and targets retrovirally expressed proteins such that they are exposed on the cytoplasmic surface of cellular membranes. This approach may be of general use for regulating the nuclear accumulation of drugs or proteins in living cells.


Assuntos
Citocromos b5/fisiologia , Citoplasma/enzimologia , Citoplasma/virologia , DNA Topoisomerases Tipo II , DNA Topoisomerases Tipo II/metabolismo , Isoenzimas/metabolismo , Retroviridae/genética , Animais , Antígenos de Neoplasias , Linhagem Celular , Citocromos b5/genética , Citocromos b5/metabolismo , Citoplasma/metabolismo , DNA Topoisomerases Tipo II/genética , Proteínas de Ligação a DNA , Etoposídeo/farmacologia , Técnicas de Transferência de Genes , Humanos , Isoenzimas/genética , Camundongos , Sinais de Localização Nuclear/genética , Oligopeptídeos/biossíntese , Oligopeptídeos/genética , Oligopeptídeos/metabolismo , Fragmentos de Peptídeos/biossíntese , Fragmentos de Peptídeos/genética , Peptídeos/genética , Peptídeos/metabolismo , Ratos , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Retroviridae/efeitos dos fármacos , Células Tumorais Cultivadas
16.
Mol Endocrinol ; 12(10): 1525-41, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9773976

RESUMO

Eukaryotic gene expression depends on a complex interplay between the transcriptional apparatus and chromatin structure. We report here a yeast model system for investigating the functional interaction between the human estrogen receptor (hER) and CTF1, a member of the CTF/NFI transcription factor family. We show that a CTF1-fusion protein and the hER transactivate a synthetic promoter in yeast in a synergistic manner. This interaction requires the proline-rich transactivation domain of CTF1. When the natural estrogen-dependent vitellogenin B1 promoter is tested in yeast, CTF1 and CTF1-fusion proteins are unable to activate transcription, and no synergy is observed between hER, which activates the B1 promoter, and these factors. Chromatin structure analysis on this promoter reveals positioned nucleosomes at -430 to -270 (+/-20 bp) and at -270 to - 100 (+/-20 bp) relative to the start site of transcription. The positions of the nucleosomes remain unchanged upon hormone-dependent transcriptional activation of the promoter, and the more proximal nucleosome appears to mask the CTF/NFI site located at - 101 to -114. We conclude that a functional interaction of hER with the estrogen response element located upstream of a basal promoter occurs in yeast despite the nucleosomal organization of this promoter, whereas the interaction of CTF1 with its target site is apparently precluded by a nucleosome.


Assuntos
Proteínas Cromossômicas não Histona , Proteínas Fúngicas/metabolismo , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismo , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Vitelogeninas/genética , Animais , Sítios de Ligação , Cromatina/genética , Cromatina/metabolismo , Cromatina/ultraestrutura , Pegada de DNA/métodos , Estradiol/farmacologia , Proteínas Fúngicas/genética , Humanos , Nucleossomos/genética , Nucleossomos/metabolismo , Regiões Promotoras Genéticas , Receptores de Estrogênio/efeitos dos fármacos , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Saccharomyces cerevisiae/metabolismo , Vitelogeninas/metabolismo , Xenopus laevis
17.
J Mol Biol ; 281(4): 631-49, 1998 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-9710536

RESUMO

We describe the preparation of nuclear extracts from yeast cells synchronised in S-phase that support the aphidicolin-sensitive, semi-conservative replication of primer-free, supercoiled plasmid in vitro. This is monitored by one and two-dimensional gel electrophoresis of replication intermediates that have incorporated [alpha-32P]dATP, by the conversion of methylated template DNA into a hemi-methylated or DpnI-resistant form, and by substitution of dTTP with the heavy derivative BrdUTP, which results in a shift in density corresponding to complete second strand synthesis. We demonstrate dependence on DNA pol delta and the pol alpha/primase complex, and are able to detect putative Okazaki fragments under ATP-limiting conditions. In contrast to the semi-conservative replication of supercoiled plasmid, linear or open-circular templates incorporate labelled nucleotides through repair synthesis that produces no significant density shift on CsCl gradients. Consistent with a true replication reaction we find that semi-conservative replication of plasmid DNA is stimulated in S-phase relative to G1-phase nuclear extracts, and is independent of the recombination-promoting factor Rad52p. Using this novel system we demonstrate that semi-conservative replication, but not polymerase activity per se, requires the activity of the DNA helicase encoded by DNA2.


Assuntos
Adenosina Trifosfatases/fisiologia , Núcleo Celular/metabolismo , DNA Helicases , Replicação do DNA/genética , DNA Super-Helicoidal/metabolismo , Saccharomyces cerevisiae/enzimologia , Afidicolina/farmacologia , Ciclo Celular/fisiologia , Centrifugação com Gradiente de Concentração , Metilação de DNA , DNA Polimerase I/metabolismo , DNA Polimerase III/metabolismo , DNA Super-Helicoidal/ultraestrutura , Nucleotídeos de Desoxiadenina/metabolismo , Desoxirribonucleases de Sítio Específico do Tipo II/metabolismo , Nucleotídeos de Desoxiuracil/metabolismo , Eletroforese em Gel Bidimensional , Microscopia Eletrônica , Proteínas Nucleares/metabolismo , Conformação de Ácido Nucleico , Plasmídeos/genética , Plasmídeos/ultraestrutura , RNA/metabolismo
18.
Zentralbl Gynakol ; 119(11): 538-44, 1997.
Artigo em Alemão | MEDLINE | ID: mdl-9480608

RESUMO

In a double-blind randomized study, the suppression of ovarian activity, the effects on the cervix and endometrium, menstrual bleeding patterns and overall tolerance were assessed during administration of two low-dose oral contraceptives (20 micrograms ethinylestradiol EE, 500 micrograms norethisterone--Eve 20, Grünenthal, Aachen; 20 micrograms EE, 150 micrograms Desogestrel--Lovelle, Organon, Munich), 118 healthy women (ages: 18 to 35 years) with comparable bioprofiles (height, weight, menstrual cycle patterns) were studied in 10 investigation centres during medication with either Eve 20 (n = 59) or Lovelle (n = 59). During 3 treatment cycles, ovarian activity was evaluated by sonographic determination of follicular size and by simultaneous assessment of serum endocrine profiles (gonadotropins LH and FSH, ovarian steroids estradiol [E2] and progesterone [P]). Treatment cycles 4 to 6 served to evaluate the patterns of menstrual bleeding and the overall subjective tolerance on each contraceptive. While on the preparations, no ovarian activity (as judged by a lack of follicular growth and suppressed sex steroid levels) was found in over 90% of all investigated cycles. Follicular activity and/or cyst formation were detected in 18 of 173 cycles (Eve 20) and in 5 of 175 cycles (Lovelle) respectively. Gonadotropin levels were suppressed (LH < 6 IU/l, FSH < 8 IU/l) in most treatment cycles (Eve 20: 76.6% vs. Lovelle: 84.8%). Serum E2 concentrations exceeding 0.1 nmol/l indicated residual follicular activity in 19.3% (Eve 20) vs. 12.2% (Lovelle) of all cycles. As estimated by serum P levels over 5 nmol/l, ovulation had presumably occurred in 4.1% (Eve 20) vs. 2.9% (Lovelle) of treatments respectively. However, when the sonographic and endocrinological data were combined, no ovulation was documented in any treatment cycle. In addition, the quality of the cervical mucus was minimal and a low endometrial thickness was found in the majority of women, indicating strong progestogen effects of both contraceptives. Menstrual irregularities (intermenstrual spotting, break-through bleeding) occurred initially on each preparation, but were mostly resolved when the pills were continued. The acceptance of each investigated drug was rated as very good or good by most subjects. These observations allow us to conclude that the rate of ovarian suppression with inhibition of follicular activity is high under low-dose oral contraceptives. The different progestogens as components of these contraceptive pills display equally good anti-conceptive effects on both the cervix and the endometrium. Furthermore, the rate of irregular menstrual bleeding is acceptable for these low-dose contraceptives. The high acceptance of each preparation suggests that such agents will have a high rate of acceptability in clinical use.


Assuntos
Anticoncepcionais Orais Sintéticos/administração & dosagem , Desogestrel/administração & dosagem , Ciclo Menstrual/efeitos dos fármacos , Ovário/efeitos dos fármacos , Adulto , Anticoncepcionais Orais Sintéticos/efeitos adversos , Desogestrel/efeitos adversos , Relação Dose-Resposta a Droga , Método Duplo-Cego , Etinilestradiol/administração & dosagem , Etinilestradiol/efeitos adversos , Feminino , Hormônios Esteroides Gonadais/sangue , Humanos , Noretindrona/administração & dosagem , Noretindrona/efeitos adversos , Testes de Função Ovariana
19.
Br J Cancer ; 73(10): 1201-9, 1996 May.
Artigo em Inglês | MEDLINE | ID: mdl-8630279

RESUMO

Drug resistance to anti-tumour agents often coincides with mutations in the gene encoding DNA topoisomerase II alpha. To examine how inactive forms of topoisomerase II can influence resistance to the chemotherapeutic agent VP-16 (etoposide) in the presence of a wild-type allele, we have expressed point mutations and carboxy-terminal truncations of yeast topoisomerase II from a plasmid in budding yeast. Truncations that terminate the coding region of topoisomerase II at amino acid (aa) 750, aa 951 and aa 1044 are localised to both the cytosol and the nucleus and fail to complement a temperature-sensitive top2-1 allele at non-permissive temperature. In contrast, the plasmid-borne wild-type TOP2 allele and a truncation at aa 1236 are nuclear localised and complement the top2-1 mutation. At low levels of expression, truncated forms of topoisomerase II render yeast resistant to levels of etoposide 2- and 3-fold above that tolerated by cells expressing the full-length enzyme. Maximal resistance is conferred by the full-length enzyme carrying a mutated active site (Y783F) or a truncation at aa 1044. The level of phosphorylation of topoisomerase II was previously shown to correlate with drug resistance in cultured cells, hence we tested mutants in the major casein kinase II acceptor sites in the C-terminal domain of yeast topoisomerase II for changes in drug sensitivity. Neither ectopic expression of the C-terminal domain alone nor phosphoacceptor site mutants significantly alter the host cell's sensitivity to etoposide.


Assuntos
DNA Topoisomerases Tipo II/metabolismo , Resistência a Medicamentos , Etoposídeo/farmacologia , Sequência de Aminoácidos , Sítios de Ligação , Caseína Quinase II , Meios de Cultura , Expressão Gênica , Teste de Complementação Genética , Dados de Sequência Molecular , Fosfoproteínas/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Saccharomyces cerevisiae/enzimologia , Deleção de Sequência , Relação Estrutura-Atividade
20.
Nucleic Acids Res ; 24(7): 1294-303, 1996 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-8614633

RESUMO

The yeast TTAGGG binding factor 1 (Tbf1) was identified and cloned through its ability to interact with vertebrate telomeric repeats in vitro. We show here that a sequence of 60 amino acids located in its C-terminus is critical for DNA binding. This sequence exhibits homologies with Myb repeats and is conserved among five proteins from plants, two of which are known to bind telomeric-related sequences, and two proteins from human, including the telomeric repeat binding factor (TRF) and the predicted C-terminal polypeptide, called orf2, from a yet unknown protein. We demonstrate that the 111 C-terminal residues of TRF and the 64 orf2 residues are able to bind the human telomeric repeats specifically. We propose to call the particular Myb-related motif found in these proteins the 'telobox'. Antibodies directed against the Tbf1 telobox detect two proteins in nuclear and mitotic chromosome extracts from human cell lines. Moreover, both proteins bind specifically to telomeric repeats in vitro. TRF is likely to correspond to one of them. Based on their high affinity for the telomeric repeat, we predict that TRF and orf2 play an important role at human telomeres.


Assuntos
Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Proteínas Fúngicas/metabolismo , Proteínas Nucleares/química , Sequências Reguladoras de Ácido Nucleico , Proteínas de Saccharomyces cerevisiae , Telômero , Sequência de Aminoácidos , Sequência de Bases , Sítios de Ligação , Primers do DNA/química , Proteínas de Ligação a DNA/imunologia , Proteínas Fúngicas/química , Proteínas Fúngicas/imunologia , Células HeLa , Humanos , Dados de Sequência Molecular , Proteínas Nucleares/metabolismo , Filogenia , Proteínas Proto-Oncogênicas/química , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-myb , Proteínas Recombinantes de Fusão , Sequências Repetitivas de Ácido Nucleico , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Transativadores/química , Transativadores/metabolismo , Fatores de Transcrição
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