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1.
Toxicol Mech Methods ; : 1-12, 2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38937256

RESUMO

Cyclosporine A (CsA) has shown efficacy against immunity-related diseases despite its toxicity in various organs, including the liver, emphasizing the need to elucidate its underlying hepatotoxicity mechanism. This study aimed to capture the alterations in genome-wide expression over time and the subsequent perturbations of corresponding pathways across species. Six data from humans, mice, and rats, including animal liver tissue, human liver microtissues, and two liver cell lines exposed to CsA toxic dose, were used. The microtissue exposed to CsA for 10 d was analyzed to obtain dynamically differentially expressed genes (DEGs). Single-time points data at 1, 3, 5, 7, and 28 d of different species were used to provide additional evidence. Using liver microtissue-based longitudinal design, DEGs that were consistently up- or down-regulated over time were captured, and the well-known mechanism involved in CsA toxicity was elucidated. Thirty DEGs that consistently changed in longitudinal data were also altered in 28-d rat in-house data with concordant expression. Some genes (e.g. TUBB2A, PLIN2, APOB) showed good concordance with identified DEGs in 1-d and 7-d mouse data. Pathway analysis revealed up-regulations of protein processing, asparagine N-linked glycosylation, and cargo concentration in the endoplasmic reticulum. Furthermore, the down-regulations of pathways related to biological oxidations and metabolite and lipid metabolism were elucidated. These pathways were also enriched in single-time-point data and conserved across species, implying their biological significance and generalizability. Overall, the human organoids-based longitudinal design coupled with cross-species validation provides temporal molecular change tracking, aiding mechanistic elucidation and biologically relevant biomarker discovery.

2.
Appl Clin Genet ; 16: 155-164, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37663123

RESUMO

Background: The Y chromosome has a specific region, namely the Azoospermia Factor (AZF) because azoospermia is typically reported in the microdeletion of the AZF region. This study aims to assess the characteristics of AZF microdeletion after screening a massive number of low sperm concentration men; and the Microdissection testicular sperm extraction (mTESE) outcomes for retrieving sperm from azoospermic patients. Materials and Methods: This retrospective multiple-center study enrolled a total of 1121 men with azoospermia, cryptozoospermia, and severe oligozoospermia from December 2016 to June 2022. An extension analysis used a total of 17 STSs to detect the position-occurring microdeletion in the AZF region (AZFa, b, c, and/or d loci). Microdissection testicular sperm extraction (mTESE) was performed to retrieve sperm in azoospermic men diagnosed AZFc microdeletion. Results: One hundred and fifty-three men carried AZF microdeletion were detected in the 1121 participants (13.64%). The incidences of AZF microdeletion were confined to AZF a, c, and d regions, both individual and concurrence, with the most common in the AZFc region accounting for 49.67%; There was no significant difference in clinical and paraclinical characteristics between the deleted regions, except FSH level (highest in AZFa microdeletion, p = 0.043). The AZFc region was the most common type of AZF microdeletion (49.67%), including complete microdeletion (4 patients) and gr/gr partial microdeletion (39 patients) with 50.00% and 63.63% in the success rate of mTESE, separately. Conclusion: The absence of AZFa and/or AZFb regions often express the most severe phenotype - azoospermia and the increasing FSH level. The AZFc region played the most common microdeletion. Microdissection testicular sperm extraction (mTESE) was the possible therapy for sperm retrieval from the testis of azoospermia men having AZFc microdeletion.

3.
Int J Med Mushrooms ; 24(3): 15-23, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35467803

RESUMO

Lentinus arcularius (=Polyporus arcularius) is a medicinal polypore mushroom recorded in Vietnam based on morphological observation. In this study, three L. arcularius isolates were identified using molecular and morphological methods. Furthermore, the antimicrobial and antioxidant activities of their intracellular and/or extracellular metabolites were investigated. The ethyl acetate and n-butanol fractions were the most active extracts against Gram-positive and Gram-negative bacteria (Escherichia coli VTCC 12014, Pseudomonas aeruginosa VTCC 12273, and Staphylococcus aureus VTCC 10658) and fungi (Candida albicans VTCC 20568, Saccharomyces cerevisiae VTCC 20146, and Aspergillus niger VTCC 30001). These fractions also showed the highest antioxidant activity by α,α-diphenyl-ß-picryl-hydrazyl as a free-radical agent or the highest percentage at 75-100% inhibition. These results suggest that L. arcularius might be a potential medicinal mushroom with antimicrobial and antioxidant effects.


Assuntos
Agaricales , Anti-Infecciosos , Basidiomycota , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Antioxidantes/farmacologia , Bactérias Gram-Negativas , Bactérias Gram-Positivas , Lentinula , Testes de Sensibilidade Microbiana , Extratos Vegetais/farmacologia , Vietnã
4.
Nat Commun ; 13(1): 2138, 2022 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-35440644

RESUMO

The accurate and efficient cleavage of shRNAs and pre-miRNAs by DICER is crucial for their gene-silencing activity. Here, we conduct high-throughput DICER cleavage assays for more than ~20,000 different shRNAs and show the comprehensive cleavage activities of DICER on these sequences. We discover a single-nucleotide bulge (22-bulge), which facilitates the cleavage activity of DICER on shRNAs and human pre-miRNAs. As a result, this 22-bulge enhances the gene-silencing activity of shRNAs and the accuracy of miRNA biogenesis. In addition, various single-nucleotide polymorphism-edited 22-bulges are found to govern the cleavage sites of DICER on pre-miRNAs and thereby control their functions. Finally, we identify the single cleavage of DICER and reveal its molecular mechanism. Our findings improve the understanding of the DICER cleavage mechanism, provide a foundation for the design of accurate and efficient shRNAs for gene-silencing, and indicate the function of bulges in regulating miRNA biogenesis.


Assuntos
MicroRNAs , Precursores de RNA , Humanos , Inativação Gênica , MicroRNAs/química , MicroRNAs/genética , Ribonuclease III/metabolismo , Precursores de RNA/genética , RNA Interferente Pequeno/genética , Polimorfismo de Nucleotídeo Único
5.
ACS Omega ; 7(11): 9397-9405, 2022 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-35350314

RESUMO

A novel polysaccharide structure (PS-T80) was collected from Ophiocordyceps sobolifera biomass and characterized via a combination of chemical and spectral analyses. Employing high-performance gel permeation chromatography (HPGPC), the average molecular weight is proven to be 7.4 × 104 Da. Furthermore, a sugar composition analysis of the obtained polysaccharide suggests two main sugars, ß-d-glucose and α-d-mannose, at a molar ratio of 2:1, respectively, in the backbone. The structure analysis unveils that PS-T80 is a mannoglucan, possessing the repeating unit of [→3)-ß-d-Glcp-(1 → 3)-α-d-Manp-(1 → 3)-ß-d-Glcp-(1→] n . Such a configuration could be considered a novel polysaccharide. Impressively, in vitro antioxidant tests revealed that PS-T80 has a promising antioxidant activity. These results demonstrate that the obtained PS is a potential bioactive material for biomedical applications.

6.
RNA Biol ; 18(11): 1716-1726, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-33382955

RESUMO

MicroRNAs (miRNAs) play critical roles in gene expression and numerous human diseases. The success of miRNA biogenesis is largely determined by the primary miRNA (pri-miRNA) processing by the DROSHA-DGCR8 complex, called Microprocessor. Here, we analysed the high-throughput pri-miRNA processing assays and secondary structures of pri-miRNAs to investigate the roles of bulges in the pri-miRNA processing. We found that bulges in multiple places control both the cleavage efficiency and accuracy of pri-miRNA processing. These bulges were shown to act on Microprocessor via its catalytic subunit, DROSHA, and function in a position and strand-dependent manner. Interestingly, we discovered that the enriched and conserved bulges, called midB, can correct DROSHA orientation on pri-miRNAs, thereby enhancing production of miRNAs. The revealed functions of the bulges help improve our understanding of pri-miRNA processing and suggest their potential roles in miRNA biogenesis regulation.


Assuntos
MicroRNAs/química , MicroRNAs/genética , Conformação de Ácido Nucleico , Proteínas de Ligação a RNA/metabolismo , Ribonuclease III/metabolismo , Pareamento de Bases , Sequência de Bases , Células HEK293 , Humanos , MicroRNAs/metabolismo , Processamento Pós-Transcricional do RNA , Proteínas de Ligação a RNA/genética , Ribonuclease III/genética
7.
Mol Cell Biochem ; 473(1-2): 167-177, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32638255

RESUMO

An active metabolite of vitamin A, all-trans retinoic acid (ATRA), is known to exert immunomodulatory functions. This study investigates the possible immune potentiating effect of ATRA on NF-κB activity in human monocytic THP-1 cells after exposure to unmethylated CpG DNA ODN2006. We observed that challenge with ODN2006 significantly enhanced the NF-κB activity of PMA-differentiated THP-1 cells. ATRA synergistically enhanced NF-κB activity of cells, in a concentration- and time-dependent manner. The enhanced NF-κB activity of PMA-differentiated THP-1 cells after ODN2006 challenge was dependent on the RAR/RXR pathway. To determine the mechanism involved in increasing in the NF-κB activity of stimulated THP-1 cells, we examined the effects of PMA and ATRA on the expression of TLR9 (a receptor of ODN2006) in THP-1 cells. PMA treatment significantly enhanced both the intracellular and cell surface expression of TLR9, while ATRA alone showed no effect. However, ATRA synergistically enhanced the cell surface TLR9 expression of PMA-differentiated cells. To determine whether the ATRA-enhanced NF-κB activity is due to the enhanced cell surface TLR9 expression, we examined NF-κB activity after treatment with anti-TLR9 blocking antibody. Results revealed that the anti-TLR9 antibody treatment almost completely reverses the ATRA-enhanced NF-κB activity, suggesting that ATRA enhances NF-κB activity through upregulation of the cell surface TLR9 expression in PMA-differentiated and unmethylated CpG challenged THP-1 cells.


Assuntos
Regulação da Expressão Gênica/efeitos dos fármacos , NF-kappa B/metabolismo , Oligodesoxirribonucleotídeos/farmacologia , Transdução de Sinais/efeitos dos fármacos , Acetato de Tetradecanoilforbol/farmacologia , Receptor Toll-Like 9/biossíntese , Tretinoína/farmacologia , Humanos , NF-kappa B/genética , Transdução de Sinais/genética , Células THP-1 , Receptor Toll-Like 9/genética
8.
Foodborne Pathog Dis ; 10(10): 873-81, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24066940

RESUMO

The European Union Reference Laboratory for Listeria monocytogenes (EURL for Lm) coordinates a European network of 35 National Reference Laboratories (NRLs), most of which perform food, environmental, and veterinary Lm strain surveillance in their respective countries. The EURL activities resulted in the recent creation of a database (EURL Lm DB). Typing and related epidemiological data submitted to the EURL Lm DB will be collected and shared by all the NRLs. For a given NRL, the only criterion required in order to submit pulsed-field gel electrophoresis (PFGE) profiles to the database was the successful participation with at least one EURL PFGE and PFGE profile interpretation Proficiency Testing (PT) trial. In this context, the EURL organized a PT trial in 2012 to evaluate the NRL's ability to perform PFGE and profile interpretation. A total of 18 NRLs took part in this study. Upon request from the Food- and Waterborne Diseases and Zoonoses Programme of the European Centre for Disease Prevention and Control, 10 National Public Health Reference Laboratories (NPHLs) also took part in this PT trial. Of the 28 participating laboratories, 16 obtained results classified as "good" or "satisfactory." These 16 laboratories included 10 NRLs (56%) and 6 NPHLs (60%). Of the 22 NRLs and NHPLs that participated in the part of the PT trial related to PFGE profile interpretation, 11 laboratories obtained good results. These 11 laboratories included eight NRLs, which therefore can now submit profiles to the EURL Lm DB. This PT trial provided a valuable opportunity to facilitate and to stimulate the sharing of reproducible PFGE profiles between human and food reference laboratories.


Assuntos
Eletroforese em Gel de Campo Pulsado/normas , Microbiologia de Alimentos , Listeria monocytogenes/classificação , Listeriose/microbiologia , Animais , Técnicas de Tipagem Bacteriana/normas , União Europeia , Humanos , Ensaio de Proficiência Laboratorial/estatística & dados numéricos , Listeria monocytogenes/genética , Listeria monocytogenes/isolamento & purificação , Listeriose/epidemiologia , Saúde Pública , Reprodutibilidade dos Testes
9.
Foodborne Pathog Dis ; 2013 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-23952473

RESUMO

Abstract The European Union Reference Laboratory for Listeria monocytogenes (EURL for Lm) coordinates a European network of 35 National Reference Laboratories (NRLs), most of which perform food, environmental, and veterinary Lm strain surveillance in their respective countries. The EURL activities resulted in the recent creation of a database (EURL Lm DB). Typing and related epidemiological data submitted to the EURL Lm DB will be collected and shared by all the NRLs. For a given NRL, the only criterion required in order to submit pulsed-field gel electrophoresis (PFGE) profiles to the database was the successful participation with at least one EURL PFGE and PFGE profile interpretation Proficiency Testing (PT) trial. In this context, the EURL organized a PT trial in 2012 to evaluate the NRL's ability to perform PFGE and profile interpretation. A total of 18 NRLs took part in this study. Upon request from the Food- and Waterborne Diseases and Zoonoses Programme of the European Centre for Disease Prevention and Control, 10 National Public Health Reference Laboratories (NPHLs) also took part in this PT trial. Of the 28 participating laboratories, 16 obtained results classified as "good" or "satisfactory." These 16 laboratories included 10 NRLs (56%) and 6 NPHLs (60%). Of the 22 NRLs and NHPLs that participated in the part of the PT trial related to PFGE profile interpretation, 11 laboratories obtained good results. These 11 laboratories included eight NRLs, which therefore can now submit profiles to the EURL Lm DB. This PT trial provided a valuable opportunity to facilitate and to stimulate the sharing of reproducible PFGE profiles between human and food reference laboratories.

10.
BMC Microbiol ; 13: 14, 2013 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-23347599

RESUMO

BACKGROUND: Listeriosis is a severe infection which mainly affects pregnant women, neonates and immuno-compromised adults. ANSES's Laboratory for Food safety has been the European Union Reference Laboratory (EURL) for L. monocytogenes in the food chain since 2006. Pulsed Field Gel Electrophoresis (PFGE) is routinely used in the EURL for the surveillance of L. monocytogenes isolated from foods, animals and the environment. One of the main EURL activities is to evaluate alternative molecular subtyping methods to PFGE, and integrate their use within the National Reference Laboratories (NRL) network. Since 2008, the United Kingdom (UK)-NRL for L. monocytogenes at the Health Protection Agency (HPA), London, has used fluorescent Amplified Fragment Length Polymorphism (fAFLP) for the routine surveillance of L. monocytogenes isolated from human clinical cases, food and food processing environments in the UK. This study compares fAFLP with PFGE for subtyping L. monocytogenes. RESULTS: A panel of 109 L. monocytogenes isolates from either human cases of listeriosis, foods, food processing environments and animals were used for the comparative evaluation. Among these, 2 strains were tested from duplicate culture by both methods. The panel also included field isolates, isolates associated with outbreaks or sporadic cases and reference strains. The two strains tested in duplicate displayed the same fAFLP and PFGE types. Strains known to be epidemiologically associated with one another were found to have unique PFGE and fAFLP types. FAFLP and PFGE divided the strains into 76 and 82 distinct profiles, or types, respectively. The discriminatory index calculated was 0.993 and 0.996 for fAFLP and PFGE, respectively. CONCLUSIONS: The discriminatory ability of fAFLP was similar to that of PFGE for the subtyping of L. monocytogenes isolates. As a less labour intensive technique fAFLP may be a better method to use than PFGE in investigating outbreaks of human listeriosis and tracking the source of contamination in food processing facilities in real time.


Assuntos
Eletroforese em Gel de Campo Pulsado , Listeria monocytogenes/classificação , Listeria monocytogenes/genética , Tipagem Molecular/métodos , Polimorfismo de Fragmento de Restrição , Feminino , Fluorescência , Microbiologia de Alimentos , Humanos , Listeria monocytogenes/isolamento & purificação , Listeriose/microbiologia , Masculino
11.
Foodborne Pathog Dis ; 9(8): 719-26, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22870985

RESUMO

The European Union Reference Laboratory for Listeria monocytogenes (EURL for L. monocytogenes) coordinates a European network of 29 National Reference Laboratories (NRLs). Depending on a national decision, NRLs undertake food, environmental, and veterinary L. monocytogenes strain surveillance in their respective countries. In the framework of the PulseNet Europe network, two pulsed-field gel electrophoresis (PFGE) subtyping proficiency testing (PT) trials were carried out in 2003 and 2006. The obtained data showed that PFGE profiles can be compared and exchanged between laboratories. However, no further PT trial had been performed since 2006. In this context, two PT trials were organized by the EURL to evaluate the ability of NRLs to perform conventional serotyping, molecular serotyping and PFGE subtyping. Eleven well-characterized isolates of L. monocytogenes were used: six and nine isolates were tested in 2009 and 2010, respectively. Three isolates were repeated between the two studies. In the 2010 panel, a strain was tested in duplicate, and two strains were related to the same epidemiological group. The strains were analyzed blind in different laboratories (17 in 2009 and 25 in 2010) using (1) their own in-house method for serotyping methods and (2) standardized protocols based on the PulseNet protocol for PFGE. For conventional serotyping, 86.0% in 2009 and 91.0% in 2010 of the serotypes obtained were in agreement with the EURL data. For molecular serotyping, 93.5% of the results in 2009 and 95.2% in 2010 matched the EURL data. For PFGE, 68.9% in 2009 and 81.7% of the combined AscI/ApaI profiles were indistinguishable from the EURL reference profiles. The variations observed could be attributed to slight standardization defaults or, in a few cases, to a failure in DNA extraction. These PT trials provided a valuable opportunity to improve the subtyping ability of NRLs and facilitate exchanges of subtyping data in the future.


Assuntos
Eletroforese em Gel de Campo Pulsado/normas , Contaminação de Alimentos , Microbiologia de Alimentos/normas , Listeria monocytogenes/classificação , Listeria monocytogenes/isolamento & purificação , Técnicas de Tipagem Bacteriana/normas , União Europeia , Microbiologia de Alimentos/métodos , Listeria monocytogenes/genética , Sorotipagem/normas
12.
Appl Environ Microbiol ; 77(8): 2788-90, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21357436

RESUMO

In order to assess antimicrobial resistance in Listeria monocytogenes, 202 food and environmental isolates from 1996 to 2006 were tested. Only four strains displayed acquired resistance. Resistance to erythromycin, tetracycline-minocycline, and trimethoprim was evidenced, and the genes erm(B), tet(M), and dfrD, already found in L. monocytogenes, were detected.


Assuntos
Farmacorresistência Bacteriana Múltipla , Listeria monocytogenes/isolamento & purificação , Antibacterianos/farmacologia , DNA Bacteriano/genética , Meio Ambiente , Microbiologia de Alimentos , França , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/genética , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase
13.
Foodborne Pathog Dis ; 7(9): 1005-12, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20528463

RESUMO

Listeriosis is a severe infection that mainly affects pregnant women, neonates, and immuno-compromised adults. The commercially available semi-automated repetitive-sequence-based polymerase chain reaction assay system, DiversiLab, has been successfully used for subtyping several species of bacteria. In this article we compare the DiversiLab System with macrorestriction analysis by pulsed-field gel electrophoresis (PFGE), which is currently the gold standard for molecular subtyping of Listeria monocytogenes. We used a panel of 116 human and food L. monocytogenes isolates for the comparative evaluation. Among these isolates, there were 4 pairs of duplicates, 13 strains were epidemiologically related, and the remaining food isolates were epidemiologically unrelated. The isolates of different serotypes represented distinct DiversiLab types (DTs) and ApaI/AscI-PFGE types except for one DT-containing isolates of two serotypes, 4b and 1/2b. The four duplicates displayed the same DT and ApaI/AscI PFGE type demonstrating the good reproducibility of the two methods. The epidemiologically related strains were clustered in the same DT and PFGE type. The Simpson's index of diversity was 0.954; 0.988; 0.994; and 0.998 for DiversiLab, AscI-PFGE, ApaI-PFGE, and AscI/ApaI-PFGE, respectively. Thus, PFGE was more discriminating than DiversiLab. However, for 1/2a serotype strains, six AscI-PFGE, three ApaI-PFGE, and one ApaI/AscI PFGE type were divided into different DTs. DiversiLab enabled a good discrimination between serotype 1/2a strains. DiversiLab is less labor intensive than PFGE and provides results in <24 hours compared with 30 hours to 3 days for PFGE from the time a pure culture of the bacteria has been obtained. On the basis of these results, DiversiLab may be useful for tracking the source of contamination in food-processing facilities and their environments. Also, DiversiLab may be more appropriate for long-term epidemiological studies where less discrimination is needed.


Assuntos
Eletroforese em Gel de Campo Pulsado , Listeria monocytogenes/classificação , Reação em Cadeia da Polimerase/métodos , Animais , Queijo/microbiologia , Microbiologia de Alimentos/métodos , Humanos , Listeria monocytogenes/genética , Listeriose/microbiologia , Carne/microbiologia , Leite/microbiologia , Sequências Repetitivas de Ácido Nucleico , Reprodutibilidade dos Testes , Sorotipagem
14.
J Microbiol Methods ; 80(2): 134-7, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19958798

RESUMO

Listeria monocytogenes serotyping is commonly used as the first level of characterisation in the epidemiological surveillance of food and clinical isolates and is therefore widely accepted. The aim of this study was to define a scheme for multiplex molecular serotyping of L. monocytogenes based on a previously described PCR assay and then to evaluate and compare this new procedure with conventional serotyping by agglutination. The study included 1204 Listeria strains collected from food products in France, from March 2005 to October 2006. Two multiplex PCR assays were designed to cluster L. monocytogenes strains into five molecular serogroups: IIa, IIb, IIc, IVa, IVb in agreement with the most commonly encountered serotypes. Amplification of the prfA gene was added to the multiplex PCR to check for L. monocytogenes species; forty-eight (4%) of the isolates tested belonged to the genus Listeria but were not L. monocytogenes. Using this first multiplex PCR, the concordance between conventional and molecular methods was 90.6%, 97.8%, 100% and 100%, for 1/2a, 1/2c, 1/2b and 4b serotypes respectively. False results were observed for some atypical 1/2a, 3a and 1/2c strains. Therefore, this lack of specificity was resolved by using an additional PCR assay based on amplification of the flaA gene, a specific target of 1/2a and 3a strains. When applying the second PCR assay to IIa and IIc molecular serogroup strains, total agreement was obtained between molecular and conventional serotyping methods with a lower level of discrimination for the molecular one. This study proposes to define a strategy for molecular serotyping using both PCR assays: a multiplex and the flaA PCR in order to assign the atypical 1/2a, 3a and 1/2c strains. Moreover, prs gene detection was added for Listeria genus recognition as a positive control in association with flaA detection. Indeed, this molecular serotyping scheme could be considered as a useful and rapid method for first-level characterisation of the most frequently encountered L. monocytogenes serotypes.


Assuntos
Técnicas de Tipagem Bacteriana/métodos , Listeria monocytogenes/classificação , Listeria monocytogenes/genética , Reação em Cadeia da Polimerase/métodos , Proteínas de Bactérias/genética , Análise por Conglomerados , DNA Bacteriano/genética , Erros de Diagnóstico , Microbiologia de Alimentos , França , Listeria monocytogenes/isolamento & purificação , Sensibilidade e Especificidade , Sorotipagem
15.
J Mol Biol ; 343(4): 1081-93, 2004 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-15476823

RESUMO

CREB-binding protein (CBP) is a large, multi-domain protein that provides a multitude of binding sites for transcriptional coactivators. The site of interaction of the tumor suppressor p53 and the oncoprotein E1A with CBP/p300 has been identified with the third cysteine-histidine-rich (CH3) domain, which incorporates two zinc-binding motifs, ZZ and TAZ2. We show that these two domains fold independently and do not interact in solution. Our experiments demonstrate conclusively that the interaction of p53 and E1A with the CH3 domain resides exclusively in the TAZ2 domain, with no contribution from the ZZ domain. We report also the three-dimensional solution structure of the ZZ domain of murine CBP. The 52 residue ZZ domain contains two twisted antiparallel beta-sheets and a short alpha-helix, and binds two zinc ions. The identity of the zinc coordinating ligands was resolved unambiguously using NMR spectroscopy of the ZZ domain substituted with (113)Cd. One zinc ion is coordinated tetrahedrally via two CXXC motifs to four cysteine side-chains, and the second zinc ion is coordinated tetrahedrally by a third CXXC motif, together with an unusual HXH motif coordinating via the N(epsilon2) atom of His40 and the N(delta1) atom of His-42. The first zinc cluster of the ZZ domain is strictly conserved, whereas the second zinc cluster shows variability in the position of the two histidine residues, reflecting the wide variety of molecules that incorporate ZZ domains. The structure of the ZZ domain shows that it belongs to the family of cross-brace zinc finger motifs that include the PHD, RING, and FYVE domains; however, its biological function is unclear. Mapping of the positions of conserved residues onto the calculated structures reveals a face containing exposed aromatic and hydrophobic side-chains, while the opposite face contains a series of conserved charged or hydrophilic groups. These homologies suggest that the ZZ domain is involved in ligand binding or molecular scaffolding, with specificity provided by the variability of the sequence that contains the helix in the murine CPB ZZ domain structure.


Assuntos
Proteínas Nucleares/química , Transativadores/química , Dedos de Zinco/fisiologia , Sequência de Aminoácidos , Animais , Proteína de Ligação a CREB , Cádmio/metabolismo , Distrofina/química , Distrofina/metabolismo , Isótopos/metabolismo , Espectroscopia de Ressonância Magnética , Camundongos , Dados de Sequência Molecular , Estrutura Terciária de Proteína , Proteína Supressora de Tumor p53/metabolismo , Zinco/metabolismo
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