Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 69.614
Filtrar
1.
J Chem Phys ; 151(12): 125101, 2019 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-31575173

RESUMO

Gene regulation is one of the most important fundamental biological processes in living cells. It involves multiple protein molecules that locate specific sites on DNA and assemble gene initiation or gene repression multimolecular complexes. While the protein search dynamics for DNA targets has been intensively investigated, the role of intermolecular interactions during the genetic activation or repression remains not well quantified. Here, we present a simple one-dimensional model of target search for two interacting molecules that can reversibly form a dimer molecular complex, which also participates in the search process. In addition, the proteins have finite residence times on specific target sites, and the gene is activated or repressed when both proteins are simultaneously present at the target. The model is analyzed using first-passage analytical calculations and Monte Carlo computer simulations. It is shown that the search dynamics exhibit a complex behavior depending on the strength of intermolecular interactions and on the target residence times. We also found that the search time shows a nonmonotonic behavior as a function of the dissociation rate for the molecular complex. Physical-chemical arguments to explain these observations are presented. Our theoretical approach highlights the importance of molecular interactions in the complex process of gene activation/repression by multiple transcription factor proteins.


Assuntos
DNA/química , Modelos Químicos , Simulação por Computador , DNA/genética , DNA/metabolismo , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Cinética , Método de Monte Carlo , Proteína Supressora de Tumor p53/química , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
2.
Acta Crystallogr C Struct Chem ; 75(Pt 8): 1091-1101, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31380792

RESUMO

A new set of differently hydrated barium and strontium squarates, namely poly[[triaqua(µ-1,2-dioxocyclobut-3-ene-1,2-diolato)barium] monohydrate], {[Ba(C4O4)(H2O)3]·H2O}n (1), poly[[diaqua(µ-1,2-dioxocyclobut-3-ene-1,2-diolato)strontium] monohydrate], {[Sr(C4O4)(H2O)2]·H2O}n (2), and poly[[triaqua(µ-1,2-dioxocyclobut-3-ene-1,2-diolato)barium/strontium(0.85/0.15)] monohydrate], {[Ba0.85Sr0.15(C4O4)(H2O)3]·H2O}n (3), is reported. The study of their crystal structures indicates that all the complexes crystallize in the triclinic space group P-1. Complexes 1 and 3 have a rare combination of squarate units coordinated through monodentate O atoms to two different metal atoms and through two bidentate O atoms to three different metal atoms. Furthermore, they have three coordinated water molecules to give a coordination number of nine. The squarate ligands in complex 2 exhibit two different coordination modes: (i) monodentate O atoms coordinated to four different Sr atoms and (ii) two monodentate O atoms coordinated to two different metal atoms with the other two O atoms bidentate to four different Sr atoms. All the compounds decompose to give the respective carbonates when heated to 800 °C, as evidenced by thermogravimetry/differential thermal analysis (TG-DTA), which are clusters of nanoparticles. Complexes 1 and 3 show additional endothermic peaks at 811 and 820 °C, respectively, indicating the phase transition of BaCO3 from an orthorhombic (α-Pmcn) to a trigonal phase (ß-R3m). All three complexes have significant DNA-binding constants, ranging from 2.45 × 104 to 9.41 × 104 M-1 against EB-CT (ethidium bromide-calf thymus) DNA and protein binding constants ranging from 1.1 × 105 to 8.6 × 105 with bovine serum albumin. The in vitro cytotoxicity of the complexes is indicated by the IC50 values, which range from 128.8 to 261.3 µg ml-1. Complex 3 shows better BSA binding, antioxidant activity against the DPPH radical and cytotoxicity than complexes 1 and 2.


Assuntos
Antineoplásicos/farmacologia , Complexos de Coordenação/farmacologia , Ciclobutanos/farmacologia , Depuradores de Radicais Livres/farmacologia , Substâncias Intercalantes/farmacologia , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/metabolismo , Bário/química , Bovinos , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Complexos de Coordenação/metabolismo , Cristalografia por Raios X , Ciclobutanos/síntese química , Ciclobutanos/química , Ciclobutanos/metabolismo , DNA/metabolismo , Depuradores de Radicais Livres/síntese química , Depuradores de Radicais Livres/química , Depuradores de Radicais Livres/metabolismo , Humanos , Ligações de Hidrogênio , Substâncias Intercalantes/síntese química , Substâncias Intercalantes/química , Substâncias Intercalantes/metabolismo , Ligantes , Células MCF-7 , Estrutura Molecular , Ligação Proteica , Soroalbumina Bovina/metabolismo , Estrôncio/química , Água/química
3.
BMC Bioinformatics ; 20(1): 414, 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31387525

RESUMO

BACKGROUND: R-loops are three-stranded nucleic acid structures that usually form during transcription and that may lead to gene regulation or genome instability. DRIP (DNA:RNA Immunoprecipitation)-seq techniques are widely used to map R-loops genome-wide providing insights into R-loop biology. However, annotation of DRIP-seq peaks to genes can be a tricky step, due to the lack of strand information when using the common basic DRIP technique. RESULTS: Here, we introduce DRIP-seq Optimized Peak Annotator (DROPA), a new tool for gene annotation of R-loop peaks based on gene expression information. DROPA allows a full customization of annotation options, ranging from the choice of reference datasets to gene feature definitions. DROPA allows to assign R-loop peaks to the DNA template strand in gene body with a false positive rate of less than 7%. A comparison of DROPA performance with three widely used annotation tools show that it identifies less false positive annotations than the others. CONCLUSIONS: DROPA is a fully customizable peak-annotation tool optimized for co-transcriptional DRIP-seq peaks, which allows a finest gene annotation based on gene expression information. Its output can easily be integrated into pipelines to perform downstream analyses, while useful and informative summary plots and statistical enrichment tests can be produced.


Assuntos
DNA/metabolismo , Imunoprecipitação , Anotação de Sequência Molecular , RNA/metabolismo , Software , Sequência de Bases , DNA/genética , Regulação da Expressão Gênica , RNA/genética
4.
Nat Commun ; 10(1): 2954, 2019 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-31273204

RESUMO

PARP-1 is rapidly recruited and activated by DNA double-strand breaks (DSBs). Upon activation, PARP-1 synthesizes a structurally complex polymer composed of ADP-ribose units that facilitates local chromatin relaxation and the recruitment of DNA repair factors. Here, we identify a function for PARP-1 in DNA DSB resection. Remarkably, inhibition of PARP-1 leads to hyperresected DNA DSBs. We show that loss of PARP-1 and hyperresection are associated with loss of Ku, 53BP1 and RIF1 resection inhibitors from the break site. DNA curtains analysis show that EXO1-mediated resection is blocked by PARP-1. Furthermore, PARP-1 abrogation leads to increased DNA resection tracks and an increase of homologous recombination in cellulo. Our results, therefore, place PARP-1 activation as a critical early event for DNA DSB repair activation and regulation of resection. Hence, our work has direct implications for the clinical use and effectiveness of PARP inhibition, which is prescribed for the treatment of various malignancies.


Assuntos
Quebras de DNA de Cadeia Dupla , DNA/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Animais , Cromatina/metabolismo , Técnicas de Silenciamento de Genes , Células HeLa , Recombinação Homóloga/genética , Humanos , Camundongos , Modelos Biológicos , Proteínas Nucleares/metabolismo , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Proteínas de Ligação a Telômeros/metabolismo , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/metabolismo
5.
Adv Exp Med Biol ; 1166: 107-117, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31301049

RESUMO

Due to its particular "silent" metabolic state, without transcription or translation, and a low level of cytosolic protective activities, mature sperm is a cellular type of aerobic organisms particularly at risk of oxidative damage. Despite the efforts of the male genital tract to treat this problem, a subcellular compartment of the sperm, the nucleus, and consequently, the paternal DNA cannot be effectively protected. There is an accumulation of evidence that oxidative damage to sperm DNA is quite common in male infertilities/subfertilities with potential harmful impacts on reproductive success, including the transgenerational inheritance of a paternal chromosomal lot carrying mutations.


Assuntos
Dano ao DNA , DNA , Infertilidade Masculina , Estresse Oxidativo , Espermatozoides , DNA/metabolismo , Humanos , Masculino , Espermatozoides/patologia
6.
J Photochem Photobiol B ; 196: 111497, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31154276

RESUMO

Systematic identification and quantification of active radical sites in a small molecule, pyrazolium 3,5-dinitrobenzoate:3,5-dinitrobenzoic acid as well as in the stable free radical (DPPH•) were carried out by Fukui functions calculation using DFT functional with B3LYP/6-311++G(d,p) level of basis set. Bioactive Lewis acid-base compound, pyrazolium 3,5-dinitrobenzoate:3,5-dinitrobenzoic acid (PDNB:DNBA) has been synthesized and crystallized by slow evaporation - solution method at 30 °C. Various functional groups and the structural arrangements were ascertained from spectral and XRD analyses, respectively. UV-vis spectral analysis was used to find out the stability of the anticipated drug for about 60 min using methanol as a solvent. Stabilization of the compound was linked to the presence of enormous N-H…O, O-H…O and C-H…O hydrogen bonding interactions identified through Hirshfeld surface analysis. Chemical stability and reactivity of the drug were validated from theoretical optimization and HOMO-LUMO analysis. Active nucleophilic, electrophilic and radical sites of PDNB:DNBA were also identified from molecular electrostatic potential analysis. Inhibition of growth of pathogens in screening experiments by the proposed drug attests its suitability in biological applications. Antioxidant activity of the compound, PDNB:DNBA, endorses its aptness for scavenging reactive radicals. Fluorimetry experiments confirm hyperchromism in DNA binding analysis proving groove mode of binding. Molecular docking explored the various modes of intermolecular interactions of the drug with microbes as well as DNA.


Assuntos
DNA/química , Nitrobenzoatos/química , Pirazóis/química , Animais , Antioxidantes/química , Aspergillus niger/efeitos dos fármacos , Sítios de Ligação , Bovinos , DNA/metabolismo , Conformação Molecular , Simulação de Acoplamento Molecular , Nitrobenzoatos/metabolismo , Nitrobenzoatos/farmacologia , Conformação de Ácido Nucleico , Teoria Quântica , Eletricidade Estática
7.
Biochemistry (Mosc) ; 84(4): 426-434, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31228934

RESUMO

The bacterium Escherichia coli has seven σ subunits that bind core RNA polymerase and are necessary for promoter recognition. It was previously shown that the σ70 and σ38 subunits can also interact with the transcription elongation complex (TEC) and stimulate pausing by recognizing DNA sequences similar to the -10 element of promoters. In this study, we analyzed the ability of the σ32, σ28, and σ24 subunits to induce pauses in reconstituted TECs containing corresponding -10 consensus elements. It was found that the σ24 subunit can induce a transcriptional pause depending on the presence of the -10 element. Pause formation is suppressed by the Gre factors, suggesting that the paused complex adopts a backtracked conformation. Some natural promoters contain potential signals of σ24-dependent pauses in the initially transcribed regions, suggesting that such pauses may have regulatory functions in transcription.


Assuntos
RNA Polimerases Dirigidas por DNA/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli/enzimologia , Transcrição Genética/fisiologia , Sequência de Bases , DNA/metabolismo , RNA Polimerases Dirigidas por DNA/genética , Proteínas de Escherichia coli/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Fator sigma/genética , Fator sigma/metabolismo , Fatores de Transcrição/metabolismo
8.
Nat Commun ; 10(1): 2420, 2019 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-31160570

RESUMO

Replication-Factor-C (RFC) and RFC-like complexes (RLCs) mediate chromatin engagement of the proliferating cell nuclear antigen (PCNA). It remains controversial how RFC and RLCs cooperate to regulate PCNA loading and unloading. Here, we show the distinct PCNA loading or unloading activity of each clamp loader. ATAD5-RLC possesses the potent PCNA unloading activity. ATPase motif and collar domain of ATAD5 are crucial for the unloading activity. DNA structures did not affect PCNA unloading activity of ATAD5-RLC. ATAD5-RLC could unload ubiquitinated PCNA. Through single molecule measurements, we reveal that ATAD5-RLC unloaded PCNA through one intermediate state before ATP hydrolysis. RFC loaded PCNA through two intermediate states on DNA, separated by ATP hydrolysis. Replication proteins such as Fen1 could inhibit the PCNA unloading activity of Elg1-RLC, a yeast homolog of ATAD5-RLC in vitro. Our findings provide molecular insights into how PCNA is released from chromatin to finalize DNA replication/repair.


Assuntos
ATPases Associadas a Diversas Atividades Celulares/metabolismo , Replicação do DNA , Proteínas de Ligação a DNA/metabolismo , DNA/metabolismo , Antígeno Nuclear de Célula em Proliferação/metabolismo , Proteína de Replicação C/metabolismo , Adenosina Trifosfatases , Trifosfato de Adenosina/metabolismo , Proteínas de Transporte/metabolismo , Cromatina/metabolismo , Endonucleases Flap/metabolismo , Humanos , Hidrólise , Saccharomyces cerevisiae , Proteínas de Saccharomyces cerevisiae/metabolismo
9.
Chem Pharm Bull (Tokyo) ; 67(6): 505-518, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31155555

RESUMO

Nucleic acid therapeutics such as antisense and small interfering RNA (siRNA) have attracted increasing attention as innovative medicines that interfere with and/or modify gene expression systems. We have developed new functional oligonucleotides that can target DNA and RNA with high efficiency and selectivity. This review summarizes our achievements, including (1) the formation of non-natural triplex DNA for sequence-specific inhibition of transcription; (2) artificial receptor molecules for 8-oxidized-guanosine nucleosides; and (3) reactive oligonucleotides with a cross-linking agent or a functionality-transfer nucleoside for RNA pinpoint modification.


Assuntos
DNA/química , RNA/química , Reagentes para Ligações Cruzadas/química , DNA/metabolismo , DNA/farmacologia , Humanos , Nucleosídeos/análogos & derivados , Nucleosídeos/farmacologia , Oligonucleotídeos/química , Oligonucleotídeos/metabolismo , Polietilenoglicóis/química , RNA/metabolismo , Telomerase/genética , Telomerase/metabolismo , Transcrição Genética/efeitos dos fármacos
10.
Cell Mol Biol Lett ; 24: 42, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31236120

RESUMO

Human bronchial epithelium (HBE)-Dp71 anti-sense(AS)cells with stably transfected Dp71 siRNA plasmids were prepared for further exploration of Dp71 biological traits in cells other than PC12. HBE-Dp71AS cells displayed increased DNA damage induced by H2O2. Apoptosis of HBE-Dp71AS cells induced by H2O2 was increased via enhancing caspase 3, caspase 8 and caspase 9. HBE-Dp71AS cells also displayed decreased proliferation and clonogenic formation. RAD51 was proved to be a new binding partner of Dp71 by co-immunoprecipitation (Ip) and immunofluorescence. Reduced RAD51 mRNA and protein levels were observed in HBE-Dp71AS cells. Decreased lamin B1, focal adhesion kinase (FAK), phosphorylated focal adhesion kinase (p-FAK) and phosphorylated protein kinase B (p-AKT) were detected in the HBE-Dp71AS cells, which functioned together with RAD51 as the molecular explanations for the character alterations of HBE-Dp71AS cells.


Assuntos
Apoptose , Dano ao DNA , Distrofina/metabolismo , Peróxido de Hidrogênio/toxicidade , Estresse Oxidativo , Rad51 Recombinase/genética , Linhagem Celular , DNA/efeitos dos fármacos , DNA/metabolismo , Reparo do DNA , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Quinase 1 de Adesão Focal/genética , Quinase 1 de Adesão Focal/metabolismo , Regulação da Expressão Gênica , Humanos , Peróxido de Hidrogênio/farmacologia , Lamina Tipo B/genética , Fosforilação , Processamento de Proteína Pós-Traducional , Rad51 Recombinase/metabolismo
11.
Biochimie ; 163: 73-83, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31150756

RESUMO

Human apurinic/apyrimidinic (AP) endonuclease APE1 is a crucial enzyme of the base excision repair (BER) pathway, which is in charge of recognition and initiation of removal of AP-sites in DNA. It is known that some single-nucleotide polymorphism (SNP) variants of APE1 have a reduced activity as compared to wild-type APE1. It has been hypothesized that genetic variation in APE1 might be responsible for an increased risk of some types of cancer. In the present work, analysis of SNPs of the APE1 gene was performed to select the set of variants having substitutions of amino acid residues on the surface of the enzyme globule and in the DNA-binding site, thereby affecting protein-protein interactions or the catalytic reaction, respectively. For seven APE1 variants (R221C, N222H, R237A, G241R, M270T, R274Q, and P311S), conformational dynamics and catalytic activities were examined. The conformational changes in the molecules of APE1 variants and in a DNA substrate were recorded as fluorescence changes of Trp and 2-aminopurine residues, respectively, using the stopped-flow technique. The results made it possible to determine the kinetic mechanism underlying the interactions of the APE1 variants with DNA substrates, to calculate the rate constants of the elementary stages, and to identify the stages of the process affected by mutation.


Assuntos
Dano ao DNA , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/genética , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/metabolismo , Polimorfismo de Nucleotídeo Único , DNA/metabolismo , Reparo do DNA , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/química , Humanos , Cinética , Modelos Moleculares , Mutação , Conformação Proteica , Especificidade por Substrato
12.
Chem Commun (Camb) ; 55(57): 8219-8222, 2019 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-31210215

RESUMO

Here we reported a new strategy to construct synthetic metabolons using dCas9-guided assembly. Three orthogonal dCas9 proteins were exploited to guide the independent and site-specific assembly of their fusion partners onto a single DNA scaffold. This new platform was applied towards the construction of a two-component cellulosome. Because of the superior binding affinity, the resulting structures exhibited both improved assembly and reducing sugar production. Conditional enzyme assembly was made possible by utilizing toehold-gated sgRNA (thgRNA), which blocks cellulosome formation until the spacer region is unblocked by a RNA trigger. This platform is highly modular owing to the ease of target synthesis, combinations of possible Cas9-fusion arrangements, and expansion to other metabolic pathways.


Assuntos
Proteína 9 Associada à CRISPR/metabolismo , RNA Guia/metabolismo , Proteína 9 Associada à CRISPR/química , Proteína 9 Associada à CRISPR/genética , Celulase/química , Celulase/genética , Celulase/metabolismo , Celulossomas/química , Celulossomas/metabolismo , DNA/química , DNA/metabolismo , Ligação Proteica , Domínios Proteicos , RNA Guia/genética
13.
J Photochem Photobiol B ; 197: 111516, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31170508

RESUMO

In the search for new therapeutic agents we have synthesized 13 new organotin(IV) carboxylate derivatives of (E)-4-((4-methoxy-2-nitrophenyl)amino)-4-oxobut-2-enoic acid. The synthesized complexes were characterized by several spectroscopic techniques. A chelating or bridging bidentate nature of the carboxylate ligand was suggested from the solid state FT-IR results. Solution state multinuclear NMR (1H, 13C and 119Sn) results reveal that the geometry around the Sn atom in triorganotin(IV) complexes is trigonal bipyramidal and in diorganotin(IV) complexes is octahedral. The ligand, (E)-4-((4-methoxy-2-nitrophenyl)amino)-4-oxobut-2-enoic acid, complex 1 and complex 2 were also analyzed by single crystal X-ray technique and the results fully supports the spectroscopic data. For 1 and 2 the geometry optimized by the single crystal X-ray analyses is distorted trigonal bipyramidal. The interaction of the studied compounds with SS-DNA was investigated by UV-Vis. Spectroscopy and Molecular docking showing an intercalative mode of binding. The evaluation of the screened compounds for cancer treatment displays even higher than that of the vincristine used as a standard drug. Similarly the performance of the tested compounds as an antileishmanial agent considers them very close in activity to the standard drug, amphotericin B. The antibacterial results show that the most of the compounds have a moderate sensitivity against the studied bacterial pathogens.


Assuntos
Complexos de Coordenação/química , Compostos Orgânicos de Estanho/química , Sítios de Ligação , Ácidos Carboxílicos/química , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/farmacologia , Cristalografia por Raios X , DNA/química , DNA/metabolismo , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Leishmania tropica/efeitos dos fármacos , Ligantes , Espectroscopia de Ressonância Magnética , Conformação Molecular , Simulação de Acoplamento Molecular , Conformação de Ácido Nucleico , Espectroscopia de Infravermelho com Transformada de Fourier
14.
Chem Commun (Camb) ; 55(52): 7514-7517, 2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31187833

RESUMO

A stem-loop clutch probe (SLCP)-based strategy has been explored to guide sequence-specific double stranded DNA (dsDNA) analysis with enhanced single-base mismatch selectivity. This assay method can also modulate the dynamic range by employing natural processes relying on distal-site mutation inhibition and allosteric activation.


Assuntos
Sondas de DNA/metabolismo , DNA/análise , Pareamento Incorreto de Bases , Técnicas Biossensoriais , DNA/química , DNA/metabolismo , Sondas de DNA/química , Corantes Fluorescentes/química , Limite de Detecção , Desnaturação de Ácido Nucleico , Hibridização de Ácido Nucleico
15.
J Chem Ecol ; 45(5-6): 429-439, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31152352

RESUMO

Animal classification is primarily based on morphological characters, even though these may not be the first to diverge during speciation. In many cases, closely related taxa are actually difficult to distinguish based on morphological characters alone, especially when there is no substantial niche separation. As a consequence, the diversity of certain groups is likely to be underestimated. Lepidoptera -moths and butterflies- represent the largest group of herbivorous insects. The extensive diversification in the group is generally assumed to have its origin in the spectacular radiation of flowering plants and the resulting abundance of ecological niches. However, speciation can also occur without strong ecological divergence. For example, reproductive isolation can evolve as the result of divergence in mate preference and the associated pheromone communication system. We combined pheromone trapping and genetic analysis to elucidate the evolutionary relationships within a complex of primitive moth species (Lepidoptera: Eriocraniidae). Mitochondrial and nuclear DNA markers provided evidence that Eriocrania semipurpurella, as currently defined by morphological characters, includes three cryptic species in Northern and Western Europe. Male moths of these cryptic species, as well as of the closely related E. sangii, exhibited relative specificity in terms of their attraction to specific ratios of two major pheromone components, (2S,6Z)-nonen-2-ol and (2R,6Z)-nonen-2-ol. Our data suggest strong assortative mating in these species in the absence of apparent niche separation, indicating that Eriocrania moths may represent an example of non-ecological speciation. Finally, our study argues in favour of combining pheromone investigations and DNA barcoding as powerful tools for identifying and delimitating species boundaries.


Assuntos
Mariposas/genética , Atrativos Sexuais/química , Animais , DNA/isolamento & purificação , DNA/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/classificação , Complexo IV da Cadeia de Transporte de Elétrons/genética , Feminino , Variação Genética , Gliceraldeído 3-Fosfato Desidrogenase (NADP+)/classificação , Gliceraldeído 3-Fosfato Desidrogenase (NADP+)/genética , Masculino , Mitocôndrias/genética , Filogenia , Atrativos Sexuais/metabolismo
16.
Eur J Med Chem ; 177: 401-413, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31158753

RESUMO

Small molecules able to bind non-canonical G-quadruplex DNA structures (G4) have been recently tested as novel potential agents for the treatment of prostate cancer thanks to their repression of aberrant androgen receptor gene. However, metastatic castration-resistant prostate cancer (mCRPC), a letal form of prostate cancer, is still incurable. Here we tested two naphthalenediimide derivatives, previously reported as multitarget agents, on a couple of relevant mCRPC cell models (DU145 and PC-3). We showed that these compounds interfere with the RAS/MEK/ERK and PI3K/AKT pathways. Interestingly, both these two biological processes depend upon Epidermal Growth Factor Receptor (EGFR) activation. By means of biological and analytical tools we showed that our compounds are efficient inducers of the structural transition of the EGFR promoter towards a G-quadruplex conformation, ultimately leading to a reduction of the receptor production. The overall result is an interesting cytotoxic profile for these two derivatives. Thanks to their activity at different steps, these compounds can open the way to novel therapeutic approaches for mCRPC that could contribute to escape resistance to selective treatments.


Assuntos
DNA/metabolismo , Quadruplex G/efeitos dos fármacos , Naftalimidas/farmacologia , Linhagem Celular Tumoral , DNA/genética , Ensaios de Seleção de Medicamentos Antitumorais , Receptores ErbB/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Ligantes , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Naftalimidas/química , Naftalimidas/metabolismo , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico
17.
BMC Infect Dis ; 19(1): 512, 2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-31182037

RESUMO

BACKGROUND: The methods routinely used to detect trichomonads in the lungs are not sensitive enough, and an effective method is urgently needed. METHOD: Primers were first designed to match the conserved area of the 18S rRNA gene of trichomonads. Then, nested PCR was carried out to detect trichomonads in bronchoalveolar lavage fluid (BALF). Finally, all positive specimens were subjected to DNA sequencing and phylogenetic analysis. RESULTS: Among 115 bronchoalveolar lavage fluid samples, ten samples tested positive in nested PCR (10/115), while no samples were positive in wet mount microscopy (0/115) (P < 0.01). Among the ten positive specimens, two were identified as Tetratrichomonas spp. and the other eight as Trichomonas tenax in phylogenetic analysis. CONCLUSIONS: Nested PCR is an effective way to detect trichomonads in bronchoalveolar lavage fluid.


Assuntos
Líquido da Lavagem Broncoalveolar/microbiologia , Reação em Cadeia da Polimerase/métodos , Trichomonas/genética , DNA/química , DNA/metabolismo , Humanos , Filogenia , Análise de Sequência de DNA , Trichomonas/classificação , Trichomonas/isolamento & purificação , Tricomoníase/diagnóstico , Tricomoníase/microbiologia
18.
Nat Commun ; 10(1): 2514, 2019 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-31175293

RESUMO

The type II nuclear receptors (NRs) function as heterodimeric transcription factors with the retinoid X receptor (RXR) to regulate diverse biological processes in response to endogenous ligands and therapeutic drugs. DNA-binding specificity has been proposed as a primary mechanism for NR gene regulatory specificity. Here we use protein-binding microarrays (PBMs) to comprehensively analyze the DNA binding of 12 NR:RXRα dimers. We find more promiscuous NR-DNA binding than has been reported, challenging the view that NR binding specificity is defined by half-site spacing. We show that NRs bind DNA using two distinct modes, explaining widespread NR binding to half-sites in vivo. Finally, we show that the current models of NR specificity better reflect binding-site activity rather than binding-site affinity. Our rich dataset and revised NR binding models provide a framework for understanding NR regulatory specificity and will facilitate more accurate analyses of genomic datasets.


Assuntos
DNA/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores X Retinoide/metabolismo , Proteínas de Ligação a DNA , Humanos , Receptores X do Fígado , Mutagênese Sítio-Dirigida , Receptores Ativados por Proliferador de Peroxissomo , Receptor de Pregnano X , Receptores de Calcitriol , Receptores do Ácido Retinoico , Receptores dos Hormônios Tireóideos
19.
Nat Commun ; 10(1): 2849, 2019 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-31253762

RESUMO

Fanconi anemia (FA) is a multigenic disease of bone marrow failure and cancer susceptibility stemming from a failure to remove DNA crosslinks and other chromosomal lesions. Within the FA DNA damage response pathway, DNA-dependent monoubiquitinaton of FANCD2 licenses downstream events, while timely FANCD2 deubiquitination serves to extinguish the response. Here, we show with reconstituted biochemical systems, which we developed, that efficient FANCD2 deubiquitination by the USP1-UAF1 complex is dependent on DNA and DNA binding by UAF1. Surprisingly, we find that the DNA binding activity of the UAF1-associated protein RAD51AP1 can substitute for that of UAF1 in FANCD2 deubiquitination in our biochemical system. We also reveal the importance of DNA binding by UAF1 and RAD51AP1 in FANCD2 deubiquitination in the cellular setting. Our results provide insights into a key step in the FA pathway and help define the multifaceted role of the USP1-UAF1-RAD51AP1 complex in DNA damage tolerance and genome repair.


Assuntos
Proteínas de Ligação a DNA/metabolismo , DNA/metabolismo , Proteína do Grupo de Complementação D2 da Anemia de Fanconi/metabolismo , Anemia de Fanconi/genética , Proteínas Nucleares/metabolismo , Proteases Específicas de Ubiquitina/metabolismo , Dano ao DNA , Proteínas de Ligação a DNA/genética , Proteína do Grupo de Complementação D2 da Anemia de Fanconi/genética , Regulação da Expressão Gênica/fisiologia , Humanos , Mutação , Proteínas Nucleares/genética , Ligação Proteica , Proteases Específicas de Ubiquitina/genética , Ubiquitinação
20.
Gene ; 706: 201-210, 2019 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-31085275

RESUMO

The functional sperm is the key factor for species continuation. The process spermatogenesis, to produce mature sperm is quite complex. It begins with the proliferation and differentiation of spermatogonia, which develop from primary spermatocytes to secondary spermatocytes and round spermatids, which eventually develop into fertile mature sperm. Spermiogenesis is the latest stage of spermatogenesis, where the round spermatids undergo a series of dramatic morphological changes and extreme condensation of chromatin to construct mature sperm with species-specific shape. During spermiogenesis, chromatin remodeling is a unique progress. It leads the nucleosome from a histone-based structure to a mostly protamine-based configuration. The main events of chromatin remodeling are the replacement of histone by histone variants, hyperacetylation, transient DNA strand breaks and repair, variants by transition proteins and finally by protamines. In this review, we synthesize and summarize the current knowledge on the progress of chromatin remodeling during spermiogenesis. We straighten out the chronological order of chromatin remodeling and illustrate the possible regulation mechanisms of each step.


Assuntos
Montagem e Desmontagem da Cromatina/fisiologia , Cromatina/fisiologia , Espermatogênese/fisiologia , Animais , Cromatina/genética , Montagem e Desmontagem da Cromatina/genética , DNA/metabolismo , Histonas/metabolismo , Humanos , Masculino , Maturação do Esperma/genética , Espermátides/metabolismo , Espermatócitos/metabolismo , Espermatogênese/genética , Espermatozoides/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA