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1.
Nature ; 626(7999): 500-504, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38356071

RESUMEN

Magnetars are neutron stars with extremely high magnetic fields (≳1014 gauss) that exhibit various X-ray phenomena such as sporadic subsecond bursts, long-term persistent flux enhancements and variable rotation-period derivative1,2. In 2020, a fast radio burst (FRB), akin to cosmological millisecond-duration radio bursts, was detected from the Galactic magnetar SGR 1935+2154 (refs. 3-5), confirming the long-suspected association between some FRBs and magnetars. However, the mechanism for FRB generation in magnetars remains unclear. Here we report the X-ray observation of two glitches in SGR 1935+2154 within a time interval of approximately nine hours, bracketing an FRB that occurred on 14 October 20226,7. Each glitch involved a significant increase in the magnetar's spin frequency, being among the largest abrupt changes in neutron-star rotation8-10 observed so far. Between the glitches, the magnetar exhibited a rapid spin-down phase, accompanied by an increase and subsequent decline in its persistent X-ray emission and burst rate. We postulate that a strong, ephemeral, magnetospheric wind11 provides the torque that rapidly slows the star's rotation. The trigger for the first glitch couples the star's crust to its magnetosphere, enhances the various X-ray signals and spawns the wind that alters magnetospheric conditions that might produce the FRB.

2.
Chaos ; 33(1): 011101, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36725633

RESUMEN

Critical physical systems with large numbers of molecules can show universal and scaling behaviors. It is of interest to know whether human societies with large numbers of people can show the same behaviors. Here, we use network theory to analyze Chinese history in periods 209 BCE-23 CE and 515-618 CE) related to the Western Han-Xin Dynasty and the late Northern Wei-Sui Dynasty, respectively. Two persons are connected when they appear in the same historical event. We find that the historical networks from two periods separated about 500 years have interesting universal and scaling behaviors, and they are small-world networks; their average cluster coefficients as a function of degree are similar to the network of movie stars. In the historical networks, the persons with larger degrees prefer to connect with persons with a small degree; however, in the network of movie stars, the persons with larger degrees prefer to connect with persons with large degrees. We also find an interesting similar mechanism for the decline or collapse of historical Chinese dynasties. The collapses of the Xin dynasty (9-23 CE) and the Sui dynasty (581-618 CE) were initiated from their arrogant attitude toward neighboring states.

3.
Community Ment Health J ; 59(8): 1549-1559, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37261659

RESUMEN

Understanding integrative approaches to mental health care can improve the responsiveness of the mental health system. Complementary and alternative medicine (CAM) use is on the rise. Research documents that many mental health consumers use CAM. This exploratory study attempts to advance awareness of CAM in mental health by examining mental health consumers' usage of CAM, their experiences in discussing CAM use with providers, and how CAM use relates to mental health recovery. Results show that 72% of the sample uses such methods, and CAM use is associated with recovery. About 54% of respondents feel CAM combined with medication is more effective than medication alone, and many endorse positive beliefs about CAM. Most consumers shared CAM use with their providers, but when they did not, the main reasons were fear of provider judgment and provider attitudes being a deterrent.

4.
FASEB J ; 35(10): e21915, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34496088

RESUMEN

During development, erythroid cells are generated by two waves of hematopoiesis. In zebrafish, primitive erythropoiesis takes place in the intermediate cell mass region, and definitive erythropoiesis arises from the aorta-gonad mesonephros. TALE-homeoproteins Meis1 and Pbx1 function upstream of GATA1 to specify the erythroid lineage. Embryos lacking Meis1 or Pbx1 have weak gata1 expression and fail to produce primitive erythrocytes. Nevertheless, the underlying mechanism of how Meis1 and Pbx1 mediate gata1 transcription in erythrocytes remains unclear. Here we show that Hif1α acts downstream of Meis1 to mediate gata1 expression in zebrafish embryos. Inhibition of Meis1 expression resulted in suppression of hif1a expression and abrogated primitive erythropoiesis, while injection with in vitro-synthesized hif1α mRNA rescued gata1 transcription in Meis1 morphants and recovered their erythropoiesis. Ablation of Hif1α expression either by morpholino knockdown or Crispr-Cas9 knockout suppressed gata1 transcription and abrogated primitive erythropoiesis. Results of chromatin immunoprecipitation assays showed that Hif1α associates with hypoxia-response elements located in the 3'-flanking region of gata1 during development, suggesting that Hif1α regulates gata1 expression in vivo. Together, our results indicate that Meis1, Hif1α, and GATA1 indeed comprise a hierarchical regulatory network in which Hif1α acts downstream of Meis1 to activate gata1 transcription through direct interactions with its cis-acting elements in primitive erythrocytes.


Asunto(s)
Células Eritroides/metabolismo , Eritropoyesis , Factor de Transcripción GATA1/metabolismo , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Proteína 1 del Sitio de Integración Viral Ecotrópica Mieloide/metabolismo , Proteínas de Pez Cebra/metabolismo , Pez Cebra/metabolismo , Animales , Inmunoprecipitación de Cromatina , Eritrocitos/citología , Eritrocitos/metabolismo , Células Eritroides/citología , Eritropoyesis/genética , Factor de Transcripción GATA1/genética , Regulación del Desarrollo de la Expresión Génica , Subunidad alfa del Factor 1 Inducible por Hipoxia/deficiencia , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Proteína 1 del Sitio de Integración Viral Ecotrópica Mieloide/deficiencia , Proteína 1 del Sitio de Integración Viral Ecotrópica Mieloide/genética , Factor de Transcripción 1 de la Leucemia de Células Pre-B/deficiencia , Factor de Transcripción 1 de la Leucemia de Células Pre-B/genética , Transcripción Genética , Pez Cebra/sangre , Pez Cebra/embriología , Pez Cebra/genética , Proteínas de Pez Cebra/deficiencia , Proteínas de Pez Cebra/genética
5.
Int J Mol Sci ; 22(6)2021 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-33801843

RESUMEN

Recessive variants of the SLC26A4 gene are globally a common cause of hearing impairment. In the past, cell lines and transgenic mice were widely used to investigate the pathogenicity associated with SLC26A4 variants. However, discrepancies in pathogenicity between humans and cell lines or transgenic mice were documented for some SLC26A4 variants. For instance, the p.C565Y variant, which was reported to be pathogenic in humans, did not exhibit functional pathogenic consequences in cell lines. To address the pathogenicity of p.C565Y, we used a genotype-based approach in which we generated knock-in mice that were heterozygous (Slc26a4+/C565Y), homozygous (Slc26a4C565Y/C565Y), and compound heterozygous (Slc26a4919-2A>G/C565Y) for this variant. Subsequent phenotypic characterization revealed that mice with these genotypes demonstrated normal auditory and vestibular functions, and normal inner-ear morphology and pendrin expression. These findings indicate that the p.C565Y variant is nonpathogenic for mice, and that a single p.C565Y allele is sufficient to maintain normal inner-ear physiology in mice. Our results highlight the differences in pathogenicity associated with certain SLC26A4 variants between transgenic mice and humans, which should be considered when interpreting the results of animal studies for SLC26A4-related deafness.


Asunto(s)
Modelos Animales de Enfermedad , Estudios de Asociación Genética/métodos , Predisposición Genética a la Enfermedad/genética , Pérdida Auditiva Sensorineural/genética , Mutación , Transportadores de Sulfato/genética , Animales , Genotipo , Pérdida Auditiva Sensorineural/metabolismo , Humanos , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Fenotipo , Transportadores de Sulfato/fisiología , Acueducto Vestibular/metabolismo , Acueducto Vestibular/patología
6.
BMC Bioinformatics ; 19(Suppl 9): 284, 2018 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-30367568

RESUMEN

BACKGROUND: Transcriptomic sequencing (RNA-seq) related applications allow for rapid explorations due to their high-throughput and relatively fast experimental capabilities, providing unprecedented progress in gene functional annotation, gene regulation analysis, and environmental factor verification. However, with increasing amounts of sequenced reads and reference model species, the selection of appropriate reference species for gene annotation has become a new challenge. METHODS: We proposed a novel approach for finding the most effective reference model species through taxonomic associations and ultra-conserved orthologous (UCO) gene comparisons among species. An online system for multiple species selection (MSS) for RNA-seq differential expression analysis was developed, and comprehensive genomic annotations from 291 reference model eukaryotic species were retrieved from the RefSeq, KEGG, and UniProt databases. RESULTS: Using the proposed MSS pipeline, gene ontology and biological pathway enrichment analysis can be efficiently achieved, especially in the case of transcriptomic analysis of non-model organisms. The results showed that the proposed method solved problems related to limitations in annotation information and provided a roughly twenty-fold reduction in computational time, resulting in more accurate results than those of traditional approaches of using a single model reference species or the large non-redundant reference database. CONCLUSIONS: Selection of appropriate reference model species helps to reduce missing annotation information, allowing for more comprehensive results than those obtained with a single model reference species. In addition, adequate model species selection reduces the computational time significantly while retaining the same order of accuracy. The proposed system indeed provides superior performance by selecting appropriate multiple species for transcriptomic analysis compared to traditional approaches.


Asunto(s)
Biología Computacional/métodos , Perfilación de la Expresión Génica/métodos , Genoma , Modelos Biológicos , Anotación de Secuencia Molecular , Transcriptoma , Animales , Bacterias/genética , Ontología de Genes , Genómica/métodos , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , Plantas/genética , Estándares de Referencia , Especificidad de la Especie
7.
Community Ment Health J ; 54(3): 302-311, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29340870

RESUMEN

A pilot evaluation study of the implementation of the Rapid Response Program, a program utilizing the ecosystemic structural family therapy model, in a rural area of Pennsylvania was conducted. This approach was implemented in children's mental health to supplant a costly model of care that had not proven to break the cycle of dependency for children with severe behavioral problems and their families. Initial results show that the Rapid Response Program appears to improve problematic family patterns and children's behavioral problems. The study results are limited by small sample size; however, the outcomes suggest that the program warrants further study using a more rigorous research design with a larger sample.


Asunto(s)
Trastornos de la Conducta Infantil/terapia , Servicios Comunitarios de Salud Mental/métodos , Terapia Familiar/métodos , Adolescente , Niño , Preescolar , Ecosistema , Femenino , Servicios de Atención de Salud a Domicilio , Humanos , Relaciones Interprofesionales , Masculino , Pennsylvania , Proyectos Piloto , Evaluación de Programas y Proyectos de Salud , Población Rural , Encuestas y Cuestionarios
9.
Curr Top Microbiol Immunol ; 392: 121-39, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26342705

RESUMEN

We formulate the Crow-Kimura, discrete-time Eigen model, and continuous-time Eigen model. These models are interrelated and we established an exact mapping between them. We consider the evolutionary dynamics for the single-peak fitness and symmetric smooth fitness. We applied the quantum mechanical methods to find the exact dynamics of the evolution model with a single-peak fitness. For the smooth symmetric fitness landscape, we map exactly the evolution equations into Hamilton-Jacobi equation (HJE). We apply the method to the Crow-Kimura (parallel) and Eigen models. We get simple formulas to calculate the dynamics of the maximum of distribution and the variance. We review the existing mathematical tools of quasi-species theory.


Asunto(s)
Evolución Molecular , Modelos Teóricos , Modelos Genéticos , Mutación
10.
Biopolymers ; 105(11): 832-9, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27422497

RESUMEN

The Poland-Fixman-Freire formalism was adapted for modeling of calorimetric DNA melting profiles, and applied to plasmid pBR 322 and long random sequences. We studied the influence of the difference (HGC -HAT ) between the helix-coil transition enthalpies of AT and GC base pairs on the calorimetric melting profile and on normalized calorimetric melting profile. A strong alteration of DNA calorimetrical profile with HGC -HAT was demonstrated. In contrast, there is a relatively slight change in the normalized profiles and in corresponding ordinary (optical) normalized differential melting curves (DMCs). For fixed HGC -HAT , the average relative deviation (S) between DMC and normalized calorimetric profile, and the difference between their melting temperatures (Tcal -Tm ) are weakly dependent on peculiarities of the multipeak fine structure of DMCs. At the same time, both the deviation S and difference (Tcal -Tm ) enlarge with the temperature melting range of the helix-coil transition. It is shown that the local deviation between DMC and normalized calorimetric profile increases in regions of narrow peaks distant from the melting temperature.


Asunto(s)
ADN/química , Calorimetría Indirecta/métodos , Desnaturalización de Ácido Nucleico
11.
J Comput Aided Mol Des ; 30(8): 639-50, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27511370

RESUMEN

Combining Lipinski's rule with the docking and steered molecular dynamics simulations and using the PubChem data base of about 1.4 million compounds, we have obtained DNA dyes Hoechst 34580 and Hoechst 33342 as top-leads for the Alzheimer's disease. The binding properties of these ligands to amyloid beta (Aß) fibril were thoroughly studied by in silico and in vitro experiments. Hoechst 34580 and Hoechst 33342 prefer to locate near hydrophobic regions with binding affinity mainly governed by the van der Waals interaction. By the Thioflavin T assay, it was found that the inhibition constant IC50 ≈ 0.86 and 0.68 µM for Hoechst 34580 and Hoechst 33342, respectively. This result qualitatively agrees with the binding free energy estimated using the molecular mechanic-Poisson Boltzmann surface area method and all-atom simulations with the AMBER-f99SB-ILDN force field and water model TIP3P. In addition, DNA dyes have the high capability to cross the blood brain barrier. Thus, both in silico and in vitro experiments have shown that Hoechst 34580 and 33342 are good candidates for treating the Alzheimer's disease by inhibiting Aß formation.


Asunto(s)
Péptidos beta-Amiloides/antagonistas & inhibidores , Péptidos beta-Amiloides/metabolismo , Bencimidazoles/farmacología , Colorantes/farmacología , Agregado de Proteínas/efectos de los fármacos , Enfermedad de Alzheimer/tratamiento farmacológico , Descubrimiento de Drogas , Humanos , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular
12.
J Chem Phys ; 145(4): 045102, 2016 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-27475397

RESUMEN

We extend a previously introduced model of stochastic gene regulation of cancer to a nonlinear case having both gene and pseudogene messenger RNAs (mRNAs) self-regulated. The model consists of stochastic Boolean genetic elements and possesses noise-induced multistability (multimodality). We obtain analytical expressions for probabilities for the case of constant but finite number of microRNA molecules which act as a noise source for the competing gene and pseudogene mRNAs. The probability distribution functions display both the global bistability regime as well as even-odd number oscillations for a certain range of model parameters. Statistical characteristics of the mRNA's level fluctuations are evaluated. The obtained results of the extended model advance our understanding of the process of stochastic gene and pseudogene expressions that is crucial in regulation of cancer.


Asunto(s)
Regulación Neoplásica de la Expresión Génica , Modelos Genéticos , Neoplasias/genética , Neoplasias/metabolismo , Seudogenes , Algoritmos , MicroARNs/metabolismo , Periodicidad , ARN Mensajero/metabolismo , Procesos Estocásticos
13.
Anal Biochem ; 479: 28-36, 2015 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-25640587

RESUMEN

Many factors that change the temperature position and interval of the DNA helix-coil transition often also alter the shape of multi-peak differential melting curves (DMCs). For DNAs with a multi-peak DMC, there is no agreement on the most useful definition for the melting temperature, Tm, and temperature melting width, ΔT, of the entire DNA transition. Changes in Tm and ΔT can reflect unstable variation of the shape of the DMC as well as alterations in DNA thermal stability and heterogeneity. Here, experiments and computer modeling for DNA multi-peak DMCs varying under different factors allowed testing of several methods of defining Tm and ΔT. Indeed, some of the methods give unreasonable "jagged" Tm and ΔT dependences on varying relative concentration of DNA chemical modifications (rb), [Na(+)], and GC content. At the same time, Tm determined as the helix-coil transition average temperature, and ΔT, which is proportional to the average absolute temperature deviation from this temperature, are suitable to characterize multi-peak DMCs. They give smoothly varying theoretical and experimental dependences of Tm and ΔT on rb, [Na(+)], and GC content. For multi-peak DMCs, Tm value determined in this way is the closest to the thermodynamic melting temperature (the helix-coil transition enthalpy/entropy ratio).


Asunto(s)
ADN/química , Desnaturalización de Ácido Nucleico , Temperatura de Transición , Animales , Composición de Base , Cationes Monovalentes/química , Bovinos , Conformación de Ácido Nucleico , Sodio/química , Termodinámica
14.
Eur Phys J E Soft Matter ; 38(9): 100, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26385736

RESUMEN

The replica technique method is applied to investigate the kinetic behavior of the coarse-grained model for the RNA molecule. A non-equilibrium phase transition of second order between the glassy phase and the ensemble of freely fluctuating structures has been observed. The non-equilibrium steady state is investigated as well and the thermodynamic characteristics of the system have been evaluated. The non-equilibrium behavior of the specific heat is discussed. Based on our analysis, we point out the state in the kinetic pathway in which the RNA molecule is most prone to hybridization.


Asunto(s)
Modelos Químicos , Modelos Moleculares , Hibridación de Ácido Nucleico , ARN/química , ARN/ultraestructura , Simulación por Computador , Conformación de Ácido Nucleico
15.
BMC Genomics ; 15 Suppl 10: S3, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25560225

RESUMEN

BACKGROUND: Short tandem repeats (STRs) are abundant in human genomes. Numerous STRs have been shown to be associated with genetic diseases and gene regulatory functions, and have been selected as genetic markers for evolutionary and forensic analyses. High-throughput next generation sequencers have fostered new cutting-edge computing techniques for genome-scale analyses, and cross-genome comparisons have facilitated the efficient identification of polymorphic STR markers for various applications. RESULTS: An automated and efficient system for detecting human polymorphic STRs at the genome scale is proposed in this study. Assembled contigs from next generation sequencing data were aligned and calibrated according to selected reference sequences. To verify identified polymorphic STRs, human genomes from the 1000 Genomes Project were employed for comprehensive analyses, and STR markers from the Combined DNA Index System (CODIS) and disease-related STR motifs were also applied as cases for evaluation. In addition, we analyzed STR variations for highly conserved homologous genes and human-unique genes. In total 477 polymorphic STRs were identified from 492 human-unique genes, among which 26 STRs were retrieved and clustered into three different groups for efficient comparison. CONCLUSIONS: We have developed an online system that efficiently identifies polymorphic STRs and provides novel distinguishable STR biomarkers for different levels of specificity. Candidate polymorphic STRs within a personal genome could be easily retrieved and compared to the constructed STR profile through query keywords, gene names, or assembled contigs.


Asunto(s)
Biología Computacional/métodos , Enfermedad/genética , Genoma Humano , Repeticiones de Microsatélite , Análisis de Secuencia de ADN/métodos , Secuencia de Bases , Cromosomas Humanos , Secuencia Conservada , Bases de Datos de Ácidos Nucleicos , Humanos , Modelos Estadísticos , Especificidad de la Especie
16.
J Comput Chem ; 35(30): 2225-30, 2014 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-25327719

RESUMEN

We perform a study of the localized surface plasmon (LSP) modes of a gold nano shell having a silica core by means of discrete dipole approximation (DDA) and spherical harmonics transform for selected wavelengths. We demonstrate an efficient solution for the near and intermediate field terms by the dyadic Green function approach and determine the optical extinction efficiency by the far field term. Using this approach, we combine the advantages of a spectral analysis along with a DDA flexibility to solve an arbitrary shaped model and demonstrate the LSP dominant mode wavelength dependency. Our approach provides a metric which may be used to quantify the effects of minor changes in the model structure, or the external dielectric environment, in optical experiments.

17.
J Comput Chem ; 35(19): 1430-7, 2014 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-24831733

RESUMEN

Aggregation of polyglutamine peptides with ß-sheet structures is related to some important neurodegenerative diseases such as Huntington's disease. However, it is not clear how polyglutamine peptides form the ß-sheets and aggregate. To understand this problem, we performed all-atom replica-exchange molecular dynamics simulations of one and two polyglutamine peptides with 10 glutamine residues in explicit water molecules. Our results show that two polyglutamine peptides mainly formed helix or coil structures when they are separated, as in the system with one-polyglutamine peptide. As the interpeptide distance decreases, the intrapeptide ß-sheet structure sometimes appear as an intermediate state, and finally the interpeptide ß-sheets are formed. We also find that the polyglutamine dimer tends to form the antiparallel ß-sheet conformations rather than the parallel ß-sheet, which is consistent with previous experiments and a coarse-grained molecular dynamics simulation.


Asunto(s)
Simulación de Dinámica Molecular , Péptidos/química
18.
J Chem Phys ; 140(20): 205104, 2014 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-24880335

RESUMEN

The phenomenon of oscillations in probability distribution functions of number of components is found for a model of stochastic gene expression. It takes place in cases of low levels of molecules or strong intracellular noise. The oscillations distinguish between more probable even and less probable odd number of particles. The even-odd symmetry restores as the number of molecules increases with the probability distribution function tending to Poisson distribution. We discuss the possibility of observation of the phenomenon in gene, protein, and mRNA expression experiments.


Asunto(s)
Regulación de la Expresión Génica , Proteínas/química , ARN Mensajero/química , Simulación por Computador , Genes , Probabilidad , Procesos Estocásticos
19.
Vet Q ; 44(1): 1-10, 2024 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-39028259

RESUMEN

Fibrinogen-fibrin degradation products (DR-70) are derived from tumor cells or metastases. Our previous study reported the diagnostic values in dogs with tumors, but no research has yet to be conducted to establish DR-70 as a prognostic marker. Herein, we investigated changes in DR-70 concentrations and disease courses in dogs with tumors. Overall survival time (OST) analysis was performed in 195 dogs with tumors, stratified with a recommended cut-off (1.514 µg/mL). Continual DR-70 measurements were performed during the medical interventions of 27 dogs with neoplasms. Clinical conditions and medical records were retrospectively reviewed. According to a cut-off value, dogs with plasma DR-70 concentrations above 1.514 µg/mL had shorter survival rates than those with concentrations below this threshold. In cases with complete or partial remission in response to treatment, the DR-70 concentration was decreased compared with that at the first visit, whereas it was increased in patients with disease progression. Our study suggested that changes in DR-70 concentration can be used as a prognostic biomarker for canine neoplasms. Furthermore, increased plasma DR-70 levels might be associated with shorter survival, and DR-70 concentrations may reflect responses to medical intervention.


Asunto(s)
Biomarcadores de Tumor , Enfermedades de los Perros , Productos de Degradación de Fibrina-Fibrinógeno , Neoplasias , Perros , Animales , Enfermedades de los Perros/sangre , Enfermedades de los Perros/mortalidad , Enfermedades de los Perros/diagnóstico , Neoplasias/veterinaria , Neoplasias/sangre , Neoplasias/mortalidad , Neoplasias/diagnóstico , Pronóstico , Estudios Retrospectivos , Masculino , Femenino , Biomarcadores de Tumor/sangre , Productos de Degradación de Fibrina-Fibrinógeno/análisis , Productos de Degradación de Fibrina-Fibrinógeno/metabolismo , Análisis de Supervivencia , Fibrinógeno/análisis
20.
Toxicol Appl Pharmacol ; 270(2): 174-84, 2013 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-23624173

RESUMEN

CYP3A proteins are the most abundant CYPs in the liver and intestines, and they play a pivotal role in drug metabolism. In mammals, CYP3A genes are induced by various xenobiotics through processes mediated by PXR. We previously identified zebrafish CYP3A65 as a CYP3A ortholog that is constitutively expressed in gastrointestinal tissues, and is upregulated by treatment with dexamethasone, rifampicin or tetrachlorodibenzo-p-dioxin (TCDD). However, the underlying mechanism of TCDD-mediated CYP3A65 transcription is unclear. Here we generated two transgenic zebrafish, Tg(CYP3A65S:EGFP) and Tg(CYP3A65L:EGFP), which contain 2.1 and 5.4 kb 5' flanking sequences, respectively, of the CYP3A65 gene upstream of EGFP. Both transgenic lines express EGFP in larval gastrointestinal tissues in a pattern similar to that of the endogenous CYP3A65 gene. Moreover, EGFP expression can be significantly induced by TCDD exposure during the larval stage. In addition, EGFP expression can be stimulated by kynurenine, a putative AHR ligand produced during tryptophan metabolism. AHRE elements in the upstream regulatory region of the CYP3A65 gene are indispensible for basal and TCDD-induced transcription. Furthermore, the AHR2 DNA and ligand-binding domains are required to mediate effective CYP3A65 transcription. AHRE sequences are present in the promoters of many teleost CYP3 genes, but not of mammalian CYP3 genes, suggesting that AHR/AHR2-mediated transcription is likely a common regulatory mechanism for teleost CYP3 genes. It may also reflect the different environments that terrestrial and aquatic organisms encounter.


Asunto(s)
Hidrocarburo de Aril Hidroxilasas/biosíntesis , Regulación Enzimológica de la Expresión Génica , Oxidorreductasas N-Desmetilantes/biosíntesis , Receptores de Hidrocarburo de Aril/genética , Proteínas de Pez Cebra/biosíntesis , Proteínas de Pez Cebra/genética , Pez Cebra/genética , Pez Cebra/metabolismo , Animales , Animales Modificados Genéticamente , Hidrocarburo de Aril Hidroxilasas/genética , Hidrocarburo de Aril Hidroxilasas/metabolismo , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Proteínas Fluorescentes Verdes/biosíntesis , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Hibridación Fluorescente in Situ , Hígado/efectos de los fármacos , Hígado/enzimología , Hígado/metabolismo , Hígado/fisiología , Oxidorreductasas N-Desmetilantes/genética , Oxidorreductasas N-Desmetilantes/metabolismo , Dibenzodioxinas Policloradas/farmacología , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Receptores de Hidrocarburo de Aril/metabolismo , Proteínas de Pez Cebra/metabolismo
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