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1.
Infection ; 42(3): 535-8, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24448875

RESUMO

A survey was performed in May 2013 to assess methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization in healthy children attending 26 municipal daycare centres in Palermo, Italy. Of the 500 children, ten (2 %) tested positive. Eight MRSA isolates were tst1-positive ST22-MRSA-IVa, spa t223; the other two isolates were identified as ST1-IVa and ST398-V, respectively. tst1-positive ST22-MRSA, spa t223 has been previously identified only in the Middle Eastern area.


Assuntos
Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Staphylococcus aureus Resistente à Meticilina/classificação , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Tipagem Molecular , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , Pré-Escolar , Coleta de Dados , Feminino , Genótipo , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina/genética , Epidemiologia Molecular , Sicília/epidemiologia
2.
Euro Surveill ; 17(33)2012 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-22913977

RESUMO

We describe polyclonal spread of colistin-resistant Klebsiella pneumoniae in an acute general hospital in Italy. Between June and December 2011, 58 colistin-resistant K. pneumoniae isolates were recovered from 28 patients admitted to different wards, but mainly in the intensive care units. All isolates were tested for drug susceptibility and the presence of beta-lactamase (bla) genes. Clonality was investigated by repetitive extragenic palindromic (rep)-PCR and multilocus sequence typing (MLST). Fifty-two isolates had minimum inhibitory concentrations (MICs) for colistin of 6-128 mg/L, carried bla(KPC3) and were attributed to sequence type ST258. The remaining six isolates were susceptible to carbapenems, exhibited MICs for colistin of 3-32 mg/L, and belonged to two different types, ST15 and ST273. Rep-PCR included all isolates in three clusters, one containing all ST258 KPC-3-producing isolates and two containing ST15 and ST273 isolates.Cross-transmission containment measures and intensification of staff and environmental hygiene could not stop the outbreak. Selective pressure and horizontal transmission probably contributed to emergence and spread of three different strains of colistin-resistant K. pneumoniae in the hospital. Strict implementation of the above measures and a wider awareness of the antimicrobial resistance threat are crucial to preserve the last therapeutic options of the multidrug-resistant Gram-negative infections.


Assuntos
Antibacterianos/farmacologia , Colistina/farmacologia , Infecção Hospitalar/epidemiologia , Surtos de Doenças , Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/isolamento & purificação , Técnicas de Tipagem Bacteriana , Carbapenêmicos/farmacologia , Infecção Hospitalar/microbiologia , DNA Bacteriano/genética , Farmacorresistência Bacteriana Múltipla , Hospitais Gerais , Humanos , Unidades de Terapia Intensiva , Itália/epidemiologia , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/enzimologia , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Quartos de Pacientes , Reação em Cadeia da Polimerase , beta-Lactamases/biossíntese , beta-Lactamases/genética
4.
Eur J Clin Microbiol Infect Dis ; 28(5): 437-46, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-18958508

RESUMO

In a bacterium like Helicobacter pylori, which is characterized by a recombinant population structure, the associated presence of genes encoding virulence factors might be considered an expression of a selective advantage conferred to strains with certain genotypes and, therefore, a potentially useful tool for predicting the clinical outcome of infections. However, differences in the geographical and ethnic prevalence of the H. pylori virulence-associated genotypes can affect their clinical predictive value and need to be considered in advance. In this study we carried out such an evaluation in a group of patients living in Sicily, the largest and most populous island in the Mediterranean Sea. cagA, vacA, babA2, hopQ, oipA, sabA, and hopZ were the H. pylori virulence-associated genes assayed; their presence, expression status or allelic homologs were detected in H. pylori DNA samples and/or isolated strains, obtained by gastric biopsy from 90 Sicilian patients with chronic gastritis, inactive (n = 37), active (n = 26), or active with peptic ulcer (n = 27). Genotypes cagA (+), vacAs1, vacAm1, babA2 (+), and hopQ I, I/II were identified in 51.8, 80.4, 35.2, 47.3, and 67.7% of the different samples respectively. Only these genotypes were associated with each other and with the active form of chronic gastritis, irrespective of the presence of a peptic ulcer. In our isolates their prevalence was more similar to values observed in the north of Italy and France than to those observed in Spain or other Mediterranean countries that are closer and climatically more similar to western Sicily.


Assuntos
Mucosa Gástrica/patologia , Infecções por Helicobacter/microbiologia , Infecções por Helicobacter/patologia , Helicobacter pylori/genética , Fatores de Virulência/genética , Adulto , Idoso , Proteínas de Bactérias/genética , Biópsia , Mucosa Gástrica/microbiologia , Gastrite/microbiologia , Gastrite/patologia , Perfilação da Expressão Gênica , Helicobacter pylori/isolamento & purificação , Humanos , Pessoa de Meia-Idade , Sicília
6.
Cancer Res ; 61(21): 7803-10, 2001 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-11691796

RESUMO

The hepatitis B virus (HBV) X protein (HBx) is a transcriptional transactivator that has been implicated in the development of HBV-related hepatocellular carcinoma. Mutations in the HBx open reading frame have been reported, but their general impact on the biological function of HBx remains unknown. To address this issue, we comparatively analyzed the structures and biological functions of HBx sequences isolated from sera and from tumor and nontumor tissues of patients with a HBV-related hepatocellular carcinoma. In addition to the HBx sequences derived from free HBV genomes, HBx from HBV integrants was also obtained from the tumor tissues by use of a HBx-Alu PCR-based approach. Sequence analysis showed that the HBx sequences derived from tumor tissues (6 of 7), particularly those isolated from HBV integrants (4 of 4), contained a deletion in the distal COOH-terminal region. Interestingly, most of the COOH-terminally truncated HBx sequences obtained from tumor tissues, in contrast to the full-length HBx isolated from the sera and nontumor tissues, lost their transcriptional activity and their inhibitory effects on cell proliferation and transformation. Importantly, although full-length HBx suppressed the focus formation induced by the cooperation of ras and myc oncogenes in primary rat embryo fibroblasts, COOH-terminally truncated HBx enhanced the transforming ability of ras and myc. Finally, by analyzing the artificial mutants, we were able to more precisely map the functional domains located at the COOH-terminal of HBx. Taken together, our results suggest a key role for the HBx COOH-terminal end in controlling cell proliferation, viability, and transformation. This study further supports the hypothesis that natural HBx mutants might be selected in tumor tissues and play a role in hepatocarcinogenesis by modifying the biological functions of HBx.


Assuntos
Carcinoma Hepatocelular/virologia , Vírus da Hepatite B/genética , Neoplasias Hepáticas/virologia , Mutação , Transativadores/fisiologia , Sequência de Aminoácidos , Apoptose/fisiologia , Carcinoma Hepatocelular/química , Carcinoma Hepatocelular/genética , Genes myc/fisiologia , Genes ras/fisiologia , Inibidores do Crescimento/genética , Inibidores do Crescimento/fisiologia , Humanos , Neoplasias Hepáticas/química , Neoplasias Hepáticas/genética , Dados de Sequência Molecular , Estrutura Terciária de Proteína , Homologia de Sequência de Aminoácidos , Transativadores/genética , Transativadores/isolamento & purificação , Ativação Transcricional , Transfecção , Proteínas Virais Reguladoras e Acessórias
7.
BMC Neurosci ; 2: 4, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11316464

RESUMO

BACKGROUND: A previous report showed that the open field behavior of rats sensitized to the dopamine agonist quinpirole satisfies 5 performance criteria for compulsive checking behavior. In an effort to extend the parallel between the drug-induced phenomenon and human obsessive-compulsive disorder (OCD), the present study investigated whether the checking behavior of quinpirole rats is subject to interruption, which is an attribute characteristic of OCD compulsions. For this purpose, the rat's home-cage was placed into the open field at the beginning or the middle of a 2-hr test. RESULTS: Introduction of the home-cage reduced checking behavior, as rats stayed inside the cage. After 40 min, checking resurfaced, as quinpirole rats exited the home-cage often. An unfamiliar cage had no such effects on quinpirole rats or saline controls. CONCLUSIONS: Checking behavior induced by quinpirole is not irrepressible but can be suspended. Results strengthen the quinpirole preparation as an animal model of OCD compulsive checking.


Assuntos
Comportamento Animal/efeitos dos fármacos , Modelos Animais de Doenças , Transtorno Obsessivo-Compulsivo/induzido quimicamente , Transtorno Obsessivo-Compulsivo/fisiopatologia , Quimpirol , Animais , Comportamento Exploratório/efeitos dos fármacos , Masculino , Atividade Motora/efeitos dos fármacos , Ratos , Ratos Long-Evans , Comportamento Espacial/efeitos dos fármacos , Fatores de Tempo
8.
Dig Liver Dis ; 34(1): 53-8, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11926574

RESUMO

BACKGROUND: Hepatitis G virus can cause chronic infection in man but the role of this agent in chronic liver disease is poorly understood. Little is known about the relation of another newly discovered agent, the TT virus, with chronic liver disease. AIM: To investigate the rate of infection with hepatitis G virus and TT virus in patients with cryptogenic chronic liver disease. PATIENTS: A total of 23 subjects with chronically raised alanine transaminase and a liver biopsy in whom all known causes of liver disease had been excluded, and 40 subjects with hepatitis C virus-related chronic liver disease. METHODS: Evaluation of anti-hepatitis G virus by enzyme immunoassay. Hepatitis G virus-RNA by polymerase chain reaction with primers from the 5' NC and NS5a regions. TT virus-DNA by nested polymerase chain reaction with primers from the ORF1 region. Results. Hepatitis G virus-RNA was detected in 4 out of 23 patients with cryptogenic chronic hepatitis and in 6 out of 40 with hepatitis C virus chronic hepatitis (17.4% vs 15% p=ns). At least one marker of hepatitis G virus infection (hepatitis G virus-RNA and/or anti-hepatitis G virus, mostly mutually exclusive) was present in 6 out of 23 patients with cryptogenic hepatitis and 16 out of 40 with hepatitis C virus liver disease (26. 1% vs 40% p=ns). T virus-DNA was present in serum in 3 subjects, 1 with cryptogenic and 2 with hepatitis C virus-related chronic liver disease. Demographic and clinical features, including stage and grade of liver histology, were comparable between hepatitis G virus-infected and uninfected subjects. Severe liver damage [chronic hepatitis with fibrosis or cirrhosis) were significantly more frequent in subjects with hepatitis C virus liver disease. CONCLUSIONS: In Southern Italy, hepatitis G virus infection is widespread among patients with chronic hepatitis, independently of parenteral risk factors. Its frequency in subjects with cryptogenic liver disease parallels that observed in hepatitis C virus chronic liver disease, thus ruling out an aetiologic role of hepatitis G virus. TT virus infection is uncommon in patients with cryptogenic or hepatitis C virus-related liver disease who do not have a history of parenteral exposure.


Assuntos
Infecções por Vírus de DNA/complicações , Infecções por Flaviviridae/complicações , Vírus GB C/isolamento & purificação , Hepatite Crônica/virologia , Hepatite Viral Humana/complicações , Torque teno virus/isolamento & purificação , Adulto , Alanina Transaminase/sangue , Feminino , Vírus GB C/genética , Humanos , Fígado/patologia , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Torque teno virus/genética
9.
J Biol Regul Homeost Agents ; 17(2): 172-5, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-14518718

RESUMO

BACKGROUND: Occult HBV infection in subjects with chronic hepatitis C is related to more severe disease outcome. It has been suggested that it might reduce sensitivity to antiviral treatment. AIMS: To assess in HBsAg negative subjects with chronic hepatitis C any effect of the presence of HBV genomes in the liver on the early kinetics of HCV-RNA under PEG-IFN plus ribavirin. PATIENTS AND METHODS: Twenty-two anti-HCV and HCV-RNA positive subjects, with biopsy-proven chronic hepatitis C (M/F 15/7; 50 +/- 8.6 years, 16 genotype 1b) were given PEG-IFN alpha 2b 1.0 microg qw plus ribavirin (800 to 1,200 mg daily according to body weight) for an intended 52 week period. Early virological response was assessed over the first 4 weeks of therapy by quantifying HCV-RNA. Occult HBV infection was assessed by testing for HBV-DNA in the liver before therapy. RESULTS: HBV genomes were found in the liver of 7 of 22 (31.4%) patients, unrelated to anti-HBc status. Kinetics of HCV-RNA during the first 4 weeks of antiviral treatment was unaffected by occult HBV infection, both in terms of absolute reduction of viral load and of number of cases with a reduction of > or = 2 log10 on treatment. CONCLUSIONS: Occult HBV infection does not affect the early phase of response to combination therapy. Further follow-up of patients into the maintenance phase of antiviral treatment and after stopping it will clarify if and when occult HBV has a role in reducing sustained virological response.


Assuntos
Hepacivirus/efeitos dos fármacos , Hepatite B/complicações , Hepatite C Crônica/tratamento farmacológico , Interferon-alfa/uso terapêutico , Polietilenoglicóis , Ribavirina/uso terapêutico , Replicação Viral/efeitos dos fármacos , Adulto , Alanina Transaminase/sangue , Antivirais/uso terapêutico , Biópsia , DNA Viral/análise , DNA Viral/isolamento & purificação , Quimioterapia Combinada , Feminino , Genótipo , Hepacivirus/classificação , Hepacivirus/genética , Hepatite B/diagnóstico , Anticorpos Anti-Hepatite B/sangue , Vírus da Hepatite B/genética , Anticorpos Anti-Hepatite C/sangue , Hepatite C Crônica/complicações , Humanos , Interferon alfa-2 , Fígado/química , Masculino , Pessoa de Meia-Idade , RNA Viral/sangue , RNA Viral/efeitos dos fármacos , Proteínas Recombinantes , Resultado do Tratamento , Carga Viral/métodos
10.
J Periodontol ; 61(9): 553-8, 1990 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2213464

RESUMO

Nine stable cardiovascular disease patients were evaluated in a double-blind cross-over trial during periodontal surgery using 2% lidocaine with epinephrine 1:100,000 or lidocaine alone. In the lidocaine with epinephrine group, epinephrine levels increased from 198 +/- 54 pg/ml to 592 +/- 166 pg/ml at 2 minutes post-injection. In the lidocaine alone group, epinephrine levels increased from a baseline of 115 +/- 34 pg/ml to 150 +/- 34 pg/ml at 2 minutes post-injection. Despite these elevations in epinephrine, no significant changes in heart rate or mean arterial pressure were noted. Plain lidocaine provided unsatisfactory levels of hemostasis and/or anesthesia during periodontal surgery. This study documents acute elevations in plasma epinephrine levels following local dental anesthesia for periodontal surgery. These elevations in plasma epinephrine failed to produce a significant cardiovascular response in a group of stable cardiovascular disease patients. This suggests that the cardiac effects of local anesthetics containing epinephrine are small and that they can be safely used in stable cardiovascular disease patients.


Assuntos
Anestesia Dentária , Anestesia Local , Doença das Coronárias/fisiopatologia , Epinefrina/farmacologia , Hipertensão/fisiopatologia , Lidocaína , Doenças Periodontais/cirurgia , Idoso , Pressão Sanguínea/efeitos dos fármacos , Doença das Coronárias/sangue , Método Duplo-Cego , Epinefrina/sangue , Frequência Cardíaca/efeitos dos fármacos , Humanos , Hipertensão/sangue , Masculino , Pessoa de Meia-Idade , Norepinefrina/sangue , Distribuição Aleatória , Retalhos Cirúrgicos
11.
J Hosp Infect ; 85(3): 233-6, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24074641

RESUMO

This article reports an outbreak of colonization by Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-Kp) sequence type (ST) 258 in a neonatal intensive care unit (NICU) in Palermo, Italy. KPC-Kp ST258 was detected by an active surveillance culture programme. Between 18th September and 14th November 2012, KPC-Kp was isolated from 10 out of 54 neonates admitted in the outbreak period. No cases of infection were recorded. Male sex was associated with colonization, whereas administration of ampicillin- sulbactam plus gentamicin was protective. Infection control interventions interrupted the spread of KPC-Kp without the need to close the NICU to new admissions.


Assuntos
Proteínas de Bactérias/metabolismo , Surtos de Doenças , Controle de Infecções/métodos , Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae/enzimologia , beta-Lactamases/metabolismo , Farmacorresistência Bacteriana Múltipla , Feminino , Humanos , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Itália/epidemiologia , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/prevenção & controle , Klebsiella pneumoniae/classificação , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/isolamento & purificação , Masculino , Tipagem de Sequências Multilocus
12.
Clin Microbiol Infect ; 17(11): E12-5, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21939470

RESUMO

In this study 45 isolates of Acinetobacter baumannii identified from patients in intensive care units of three different hospitals and from pressure ulcers in home care patients in Palermo, Italy, during a 3-month period in 2010, were characterized. All isolates were resistant to at least three classes of antibiotics, but susceptible to colistin and tygecycline. Forty isolates were non-susceptible to carbapenems. Eighteen and two isolates, respectively, carried the bla(OXA-23-like) and the bla(OXA-58-like) genes. One strain carried the VIM-4 gene. Six major rep-PCR subtype clusters were defined, including isolates from different hospitals or home care patients. The sequence type/pulsed field gel electrophoresis group ST2/A included 33 isolates, and ST78/B the remaining 12. ST2 clone proved to be predominant, but a frequent involvement of the ST78 clone was evident.


Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/isolamento & purificação , Infecções Comunitárias Adquiridas/microbiologia , Infecção Hospitalar/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/genética , Antibacterianos/farmacologia , Análise por Conglomerados , Farmacorresistência Bacteriana Múltipla , Eletroforese em Gel de Campo Pulsado , Genótipo , Serviços de Assistência Domiciliar , Humanos , Unidades de Terapia Intensiva , Itália , Testes de Sensibilidade Microbiana , Tipagem Molecular , Tipagem de Sequências Multilocus , beta-Lactamases/genética
15.
J Viral Hepat ; 15(1): 66-70, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18088247

RESUMO

Monitoring of HCV-RNA in blood during antiviral therapy is performed mostly by commercially available reverse transcription polymerase chain reaction-based (RT-PCR) assays, with a lower detection limit of 30-50 IU/mL of HCV-RNA. Use of different tests in the pivotal trials of combination therapy has generated some discordance, in terms of predictive value of the early virological response (EVR). To evaluate whether the use of a more sensitive test, as a qualitative assay based on transcription mediated amplification (TMA) with a lower detection limit of 5-10 IU/mL of HCV-RNA, may obtain a better prediction of EVR and of the ultimate virological outcome, we retrospectively evaluated serial samples from 108 naïve patients with HCV genotype 1 chronic hepatitis, treated with pegylated alpha2b interferon plus ribavirin for 48 weeks and with a 24 weeks stopping rule. Serum samples of patients, obtained during treatment at weeks 4, 12, 24 and 48 and after treatment at week 24, were evaluated by TMA. Comparison of the RT-PCR and TMA assays for the qualitative detection of HCV-RNA showed no significant differences in performance when these tests were used at the end of the treatment period for assessing patients without an on-treatment virological response and those who eventually obtain a sustained virological response. Our results show instead that the use of TMA assay to detect HCV-RNA at 12 and 24 weeks of the combination therapy is more effective than RT-PCR in identifying patients with the highest probability of sustained HCV-RNA clearance.


Assuntos
Quimioterapia Combinada , Hepacivirus/isolamento & purificação , Hepatite C Crônica/tratamento farmacológico , Técnicas de Amplificação de Ácido Nucleico/métodos , RNA Viral/isolamento & purificação , Transcrição Gênica , Antivirais/uso terapêutico , Feminino , Genótipo , Hepacivirus/classificação , Hepacivirus/genética , Hepatite C Crônica/virologia , Humanos , Interferon alfa-2 , Interferon-alfa/uso terapêutico , Masculino , Polietilenoglicóis , Valor Preditivo dos Testes , RNA Viral/sangue , RNA Viral/genética , Proteínas Recombinantes , Estudos Retrospectivos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Ribavirina/uso terapêutico , Sensibilidade e Especificidade , Resultado do Tratamento
17.
Hepatology ; 30(3): 677-81, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10462374

RESUMO

Deletions of the Tg737 gene, whose product is involved in liver oval cell proliferation, differentiation, and ploidy control, have been recently shown in chemically induced rat liver tumors and in a limited series of patients with hepatocellular carcinoma (HCC). Thus, Tg737 has been proposed as a candidate new liver-specific tumor suppressor gene. To investigate this important issue, we analyzed the structure and expression pattern of the Tg737 gene in a group of 23 tumorous and adjacent nontumorous liver tissues, by combining polymerase chain reaction (PCR) and Southern and Northern blot-based analyses. We failed to identify deletions or gross alterations of the Tg737 gene by both PCR and Southern blot analyses. Northern blots showed comparable accumulation of normal Tg737 transcripts in both tumorous and nontumorous tissues. Collectively, therefore, our results do not support the hypothesis of frequent Tg737 genetic alterations in human HCC.


Assuntos
Carcinoma Hepatocelular/genética , Genes Supressores de Tumor , Neoplasias Hepáticas/genética , Proteínas/genética , Proteínas Supressoras de Tumor , Southern Blotting , Éxons , Humanos , Reação em Cadeia da Polimerase
18.
Proc Natl Acad Sci U S A ; 91(25): 12322-6, 1994 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-7991625

RESUMO

The sea urchin early H2A histone gene, like the other four members of the repeating units, is transiently expressed during very early development. To investigate the mechanisms underlying the faithful expression of the early H2A gene, we focused our attention on the modulator element. We showed by DNase I cleavage protection patterns that the modulator includes the upstream sequence element 1 (USE1) and mapped at nucleotides -137 to -108 in the early H2A gene promoter. Functional tests conducted by microinjection into sea urchin embryos then showed that the modulator element binds the transcriptional factor called modulator-binding factor 1 (MBF-1). We found in fact that coinjection of an excess of the MBF-1-binding site, either as the modulator or as the USE1, efficiently impaired the activity of the H2A promoter. An unexpected finding was the expression of the reporter gene from the early H2A promoter at the gastrula stage of embryonic development, when the early histone genes are transcriptionally silent. In addition, we also found that the modulator element was active at the gastrula stage. The potential enhancer activity of the modulator was tested by microinjecting several constructs containing single or multiple copies of the modulator element placed 5' or 3' to a thymidine kinase gene (tk) promoter in both sea urchin embryos and Xenopus laevis oocytes and determining the expression of a reporter chloramphenicol acetyltransferase gene under the control of the linked tk promoter. We found that an oligonucleotide bearing the MBF-1-binding site activates the expression of the reporter gene independently of the position and orientation. We conclude that the modulator binds the MBF-1 activator and that it is a transcriptional enhancer of the early H2A histone gene.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Elementos Facilitadores Genéticos , Histonas/genética , Regiões Promotoras Genéticas , Ouriços-do-Mar/metabolismo , Fatores de Transcrição/metabolismo , Animais , Sequência de Bases , Sítios de Ligação , Núcleo Celular/metabolismo , Cloranfenicol O-Acetiltransferase/biossíntese , Primers do DNA , Desoxirribonuclease I , Embrião não Mamífero/fisiologia , Feminino , Histonas/biossíntese , Dados de Sequência Molecular , Oócitos/fisiologia , Proteínas Recombinantes/biossíntese , Sequências Repetitivas de Ácido Nucleico , Ouriços-do-Mar/genética , Homologia de Sequência do Ácido Nucleico , Especificidade da Espécie , TATA Box , Xenopus
19.
Proc Natl Acad Sci U S A ; 90(14): 6854-8, 1993 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-8341709

RESUMO

To shed some light on the mechanisms involved in the coordinate regulation of the early histone gene set during sea urchin development, we tested the hypothesis that the upstream sequence element USE1, previously identified in the early H2A modulator, could also participate in the transcription of the early histone H3 gene. We found by DNAse I protection analysis and by competition in electrophoretic mobility-shift experiments that two sequence elements of the H3 promoter closely resembled the USE1-H2A sequence in their binding activity for nuclear factors from 64-cell stage embryos. These modulator binding factor 1 (MBF-1)-related factors seem to recognize the ACAGA motif that is conserved between the USE1-like sequences of both H2A and H3 promoters. In fact, excess oligonucleotide containing a mutated USE1-H2A element in which the ACAGA sequence was mutated to AGTCA failed to compete with the USE1 sites of both H2A and H3 genes for interaction with MBF-1. Finally, in vivo transcriptional analysis in both Xenopus and sea urchin showed that an excess of USE1-H2A element efficiently competed for the activity of the H3 promoter. From these results we conclude that MBF-1 is a transcription factor conserved between sea urchin and frog and that MBF-1 or related transcription factors are involved in the coordinate expression of both H2A and H3 early histone genes.


Assuntos
Regulação da Expressão Gênica , Histonas/biossíntese , Ouriços-do-Mar/genética , Transcrição Gênica , Animais , Sequência de Bases , Núcleo Celular/química , Microinjeções , Dados de Sequência Molecular , Oócitos , Óvulo , Regiões Promotoras Genéticas/genética , Ouriços-do-Mar/embriologia , Xenopus laevis
20.
Biol Chem ; 380(2): 159-65, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10195423

RESUMO

Transcription of the sea urchin early histone genes occurs transiently during early cleavage, reaching the maximum at the morula stage and declining to an undetectable level at the gastrula stage. To identify the regulatory elements responsible for the timing and the levels of transcription of the H2A gene, we used promoter binding studies in nuclear extracts and microinjection of a CAT transgene driven by the early H2A promoter. We found that morula and gastrula nuclear proteins produced indistinguishable DNase I footprint patterns on the H2A promoter. Two sites of interactions, centred on the modulator/enhancer and on the CCAAT box respectively, were detected. Deletion of the modulator or coinjection of an excess of modulator sequences severely affected the expression of two transgenes driven by the enhancer-less and modulator-containing H2A promoter. Finally, a DNA fragment containing 3' coding and post-H2A spacer sequences, where upon silencing three micrococcal nuclease hypersensitive sites were previously mapped, specifically repressed at the gastrula stage the expression of the transgene driven by the H2A promoter. These results indicate that the modulator is essential for the expression of early H2A gene and that sequences for downregulation are localized near the 3' end of the H2A gene.


Assuntos
Regiões 3' não Traduzidas , Regulação da Expressão Gênica , Histonas/genética , Animais , Sequência de Bases , Gástrula , Dados de Sequência Molecular , Ouriços-do-Mar , Fatores de Transcrição/metabolismo , Ativação Transcricional , Transgenes
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