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1.
Vestn Oftalmol ; 135(4): 10-18, 2019.
Artigo em Russo | MEDLINE | ID: mdl-31573552

RESUMO

PURPOSE: To evaluate phenotype-genotype correlations in patients with inherited retinal diseases (IRD) with mutation p.G1961E in the ABCA4 gene. MATERIAL AND METHODS: The study included 20 patients with p.G1961E mutation in the heterozygous state in the ABCA4 gene who underwent complete ophthalmic examination, as well as high-performance parallel sequencing of the coding sequences and adjacent areas of the introns of the ABCA4, ELOVL4, PROM1, CNGB3 genes. RESULTS: The p.G1961E mutation was detected in heterozygous state with missense mutations, splice site mutations, a frameshift duplication, and a nonsense mutation in 18 patients, a second mutation was not detected in 2 patients. The duration of the disease in 4 patients was 2-5 years, which made it impossible to assess the morphofunctional changes in dynamics. In 13 of the 16 patients with IRD duration of 29±14 years and p.G1961E mutation in the ABCA4 gene the course of the disease was relatively mild: visual acuity of 0.15±0.07, loss of visual acuity averaging 0.037±0.019 per year, absolute/relative scotoma within 5-20°, and 3.52±1.21 mm loss of ellipsoid photoreceptor zone in the macular area according to OCT. In 3 patients, including one without a second mutation in the ABCA4 gene, better pronounced changes were revealed. Multifocal electroretinogram was altered in all 20 cases. In 7 of the 8 patients with p.G1961E in the heterozygous state in combination with complex mutation p.[L541P;A1038V], as well as in 2 patients without a second mutation, full-field electroretinography (Ganzfeld; ffERG) had changes (abnormalities) of varying intensity. CONCLUSION: A frequent mutation in the ABCA4 gene - p.G1961E - is associated with a relatively mild course of IRD in 81% of cases, even in the presence of a second, severe mutation. However, in rare cases a more severe phenotype of the IRD in patients with p.G1961E mutation can be observed, which may be associated with other genetic factors. In patients with the p.G1961E mutation in heterozygous state with p.[L541P;A1038V], ffERG changes (abnormalities) were revealed.


Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Degeneração Macular , Doenças Retinianas , Genótipo , Humanos , Mutação , Fenótipo
2.
J Agric Food Chem ; 67(42): 11805-11814, 2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31566383

RESUMO

The impact of cross-breeding two low phytic acid (lpa) rice mutants on the content of phytic acid and the metabolite profile of the resulting double mutant was investigated. Progenies resulting from the cross of Os-lpa-XS110-1, a rice mutant carrying the myo-inositol kinase (OsMIK) mutated gene, and Os-lpa-XS110-2, with the multidrug resistance-associated protein ABC transporter gene 5 (OsMRP5) as the mutation target, were subjected to high-pressure ion chromatography. The reduction of the phytic acid content in the double mutant (-63%) was much more pronounced than in the single mutants (-26 and -47%). Gas chromatography-based metabolite profiling revealed a superimposition of the metabolite profiles inherited from the lpa progenitors in the double mutant progenies; the resulting metabolite signature was predominated by the OsMIK mutation effect. The study demonstrated that cross-breeding of two single lpa mutants can be employed to generate double lpa rice mutants showing both a significant reduction in the content of phytic acid and the imprinting of a specific mutation-induced metabolite signature.


Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Hibridização Genética , Oryza/química , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Ácido Fítico/análise , Proteínas de Plantas/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Mutação , Oryza/genética , Oryza/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Ácido Fítico/metabolismo , Proteínas de Plantas/metabolismo , Sementes/química , Sementes/genética , Sementes/metabolismo
3.
Brain Nerve ; 71(10): 1071-1079, 2019 Oct.
Artigo em Japonês | MEDLINE | ID: mdl-31588051

RESUMO

Next generation sequencing (NGS) technology has dramatically influenced the field of omics studies, such as genomics and transcriptomics. It is now possible to access a significant number of previously known and novel genomic variants through NGS. Although the effective manipulation and accurate interpretation of the inordinate amount of data may pose a considerable challenge, it enables us to identify specific genes responsible for causing or influencing the susceptibility to a plethora of diseases. Alzheimer's disease (AD) is the most common etiology of dementia in the elderly (approximately 60-70%). The current research trend of AD genetics focuses on the analysis of rare variants (allelic frequency <1%) instead of common variants (allelic frequency >1%) to identify AD-associated genes/variants. A number of genes (such as TREM2, ABCA7, SORL1) that carry rare pathogenic variants have reportedly conferred susceptibility to AD with stronger genetic risk effects (odds ratio >2.0). Here, we are going to introduce a small part of the latest many attractive findings about AD genetic researches.


Assuntos
Doença de Alzheimer/genética , Predisposição Genética para Doença , Transportadores de Cassetes de Ligação de ATP/genética , Alelos , Frequência do Gene , Testes Genéticos , Genômica , Humanos , Proteínas Relacionadas a Receptor de LDL/genética , Glicoproteínas de Membrana/genética , Proteínas de Membrana Transportadoras/genética , Receptores Imunológicos/genética
4.
Adv Exp Med Biol ; 1141: 13-100, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31571164

RESUMO

The transport of specific molecules across lipid membranes is an essential function of all living organisms. The processes are usually mediated by specific transporters. One of the largest transporter families is the ATP-binding cassette (ABC) family. More than 40 ABC transporters have been identified in human, which are divided into 7 subfamilies (ABCA to ABCG) based on their gene structure, amino acid sequence, domain organization, and phylogenetic analysis. Of them, at least 11 ABC transporters including P-glycoprotein (P-GP/ABCB1), multidrug resistance-associated proteins (MRPs/ABCCs), and breast cancer resistance protein (BCRP/ABCG2) are involved in multidrug resistance (MDR) development. These ABC transporters are expressed in various tissues such as the liver, intestine, kidney, and brain, playing important roles in absorption, distribution, and excretion of drugs. Some ABC transporters are also involved in diverse cellular processes such as maintenance of osmotic homeostasis, antigen processing, cell division, immunity, cholesterol, and lipid trafficking. Several human diseases such as cystic fibrosis, sitosterolemia, Tangier disease, intrahepatic cholestasis, and retinal degeneration are associated with mutations in corresponding transporters. This chapter will describe function and expression of several ABC transporters (such as P-GP, BCRP, and MRPs), their substrates and inhibitors, as well as their clinical significance.


Assuntos
Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/antagonistas & inibidores , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Fenômenos Fisiológicos Celulares , Resistência a Múltiplos Medicamentos/genética , Regulação da Expressão Gênica , Humanos , Filogenia
5.
Cell Physiol Biochem ; 53(2): 400-412, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31403270

RESUMO

BACKGROUND/AIMS: Mutations in ABCA4 cause Stargardt macular degeneration, which invariably ends in legal blindness. We studied two common mutants, A1038V (in NBD1) and G1961E (in NBD2), with the purpose of exploring how they interact with the cell's quality control mechanism. The study was designed to determine how these mutants can be rescued. METHODS: We expressed wt and mutant ABCA4 in HEK293 cells and studied the effect of the mutations on trafficking and processing and the ability of correctors to rescue them. We used a combination of western blotting, confocal microscopy and surface biotinylation coupled with pulldown of plasma membrane proteins. RESULTS: G1961E is sensitive to inhibitors of the aggresome, tubacin and the lysosome, bafilomycin A. Both mutants cause a reduction in heat shock protein, Hsp27. Incubation of HEK293 cells expressing the mutants with VX-809, an FDA approved drug for the treatment of cystic fibrosis, increased the levels of A1038V and G1961E by 2- to 3-fold. Importantly, VX-809 increased the levels of both mutants at the plasma membrane suggesting that trafficking had been restored. Transfecting additional Hsp27 to the cells also increased the steady state levels of both mutants. However, in combination with VX-809 the addition of Hsp27 caused a dramatic increase in the protein expression particularly in the G1961 mutant which increased approximately 5-fold. CONCLUSION: Our results provide a new mechanism for the rescue of ABCA4 trafficking mutants based on the restoration of Hsp27. Our results provide a pathway for the treatment of Stargardt disease.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Aminopiridinas/farmacologia , Benzodioxóis/farmacologia , Transportadores de Cassetes de Ligação de ATP/genética , Aminopiridinas/uso terapêutico , Anilidas/farmacologia , Benzodioxóis/uso terapêutico , Membrana Celular/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Células HEK293 , Proteínas de Choque Térmico HSP27/metabolismo , Humanos , Ácidos Hidroxâmicos/farmacologia , Leupeptinas/farmacologia , Lisossomos/metabolismo , Degeneração Macular/congênito , Degeneração Macular/tratamento farmacológico , Degeneração Macular/metabolismo , Degeneração Macular/patologia , Mutação , Transporte Proteico/efeitos dos fármacos
6.
J Cancer Res Clin Oncol ; 145(8): 1949-1976, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31292714

RESUMO

PURPOSE: Efflux transporters of the adenosine triphosphate-binding cassette (ABC)-superfamily play an important role in the development of multidrug resistance (multidrug resistant; MDR) in cancer. The overexpression of these transporters can directly contribute to the failure of chemotherapeutic drugs. Several in vitro and in vivo models exist to screen for the efficacy of chemotherapeutic drugs against MDR cancer, specifically facilitated by efflux transporters. RESULTS: This article reviews a range of efflux transporter-based MDR models used to test the efficacy of compounds to overcome MDR in cancer. These models are classified as either in vitro or in vivo and are further categorised as the most basic, conventional models or more complex and advanced systems. Each model's origin, advantages and limitations, as well as specific efflux transporter-based MDR applications are discussed. Accordingly, future modifications to existing models or new research approaches are suggested to develop prototypes that closely resemble the true nature of multidrug resistant cancer in the human body. CONCLUSIONS: It is evident from this review that a combination of both in vitro and in vivo preclinical models can provide a better understanding of cancer itself, than using a single model only. However, there is still a clear lack of progression of these models from basic research to high-throughput clinical practice.


Assuntos
Transportadores de Cassetes de Ligação de ATP/fisiologia , Antineoplásicos/isolamento & purificação , Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Modelos Biológicos , Transportadores de Cassetes de Ligação de ATP/antagonistas & inibidores , Transportadores de Cassetes de Ligação de ATP/genética , Antineoplásicos/farmacologia , Transporte Biológico/efeitos dos fármacos , Transporte Biológico/genética , Técnicas de Cultura/métodos , Técnicas de Apoio para a Decisão , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Resistência a Múltiplos Medicamentos/genética , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Humanos , Especificidade de Órgãos , Seleção de Pacientes
7.
Internist (Berl) ; 60(8): 871-877, 2019 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-31254003

RESUMO

Sitosterolemia or phytosterolemia is a rare autosomal recessive hereditary lipid storage disorder. It is caused by homozygous or compound heterozygous mutations in one of the two ABCG5 and ABCG8 genes encoding the intestinal and hepatic heterodimer ABCG5 (sterolin 1)/ABCG8 (sterolin 2) efflux transporters. These mutations lead to intestinal hyperabsorption and reduced hepatic secretion of cholesterol and plant sterols with subsequent accumulation of phytosterols and cholesterol in plasma and deposition in tissue (xanthoma). Phytosterols are found mainly in vegetable oils, margarine, nuts, grains, soybeans and avocados. Patients with sitosterolemia show extreme phenotypic heterogeneity from almost asymptomatic individuals to those with combined severe hypercholesterolemia at a young age, leading to increased atherosclerosis and premature cardiac death. Early abnormalities include hemolytic anemia with stomatocytosis, macrothrombocytopenia and splenomegaly. In addition to strict avoidance of phytosterol-containing foods, the use of the sterol absorption inhibitor ezetimibe, possibly in combination with the bile acid-binding resin cholestyramine, is the most effective treatment option.


Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Hipercolesterolemia/patologia , Enteropatias/patologia , Erros Inatos do Metabolismo Lipídico/genética , Mutação/genética , Fitosteróis/efeitos adversos , Fitosteróis/sangue , Membro 5 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Membro 8 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Humanos , Hipercolesterolemia/sangue , Erros Inatos do Metabolismo Lipídico/complicações , Erros Inatos do Metabolismo Lipídico/patologia
8.
Expert Opin Drug Metab Toxicol ; 15(7): 577-593, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31185182

RESUMO

Introduction: Chemotherapy remains the only option for advanced cancer patients when other alternatives are not feasible. Nevertheless, the success rate of this type of therapy is often low due to intrinsic or acquired mechanisms of chemoresistance. Among them, drug extrusion from cancer cells through ATP-binding cassette (ABC) proteins plays an important role. ABC pumps are primary active transporters involved in the barrier and secretory functions of many healthy cells. Areas covered: In this review, we have used The Cancer Genome Atlas (TCGA) database to explore the relationship between the expression of the major ABC proteins involved in cancer chemoresistance in the most common types of cancer, and the drugs used in the treatment of these tumors that are substrates of these pumps. Expert opinion: From unicellular organisms to humans, several ABC proteins play a major role in detoxification processes. Cancer cells exploit this ability to protect themselves from cytostatic drugs. Among the ABC pumps, MDR1, MRPs and BCRP are able to export many antitumor drugs and are expressed in several types of cancer, and further up-regulated during treatment. This event results in the enhanced ability of tumor cells to reduce intracellular drug concentrations and hence the pharmacological effect of chemotherapy.


Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Antineoplásicos/farmacologia , Neoplasias/tratamento farmacológico , Transportadores de Cassetes de Ligação de ATP/metabolismo , Bases de Dados Genéticas , Resistencia a Medicamentos Antineoplásicos/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias/genética , Regulação para Cima
9.
Int J Mol Sci ; 20(10)2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31096671

RESUMO

ATP-binding cassette (ABC) transporters are a superfamily of proteins that transport nutrient substances and secondary metabolites through cell membranes. They also act as an uptake system for N,N'-diacetylchitobiose (GlcNAc)2 in Streptomyces coelicolor. (GlcNAc)2 is an important inducer of chitinase. However, whether the ABC transporter in Trichoderma spp. is also responsible for (GlcNAc)2 uptake and chitinase induction has not yet been confirmed. In this study, we applied RNA interference and overexpression technologies to alter the expression level of the ABC-B transporter in order to detect changes in its transportation ability and the expression level of inducible endo-chitinase ECH42-an important biocontrol enzyme in Trichoderma asperellum. The results revealed that, after interference with the expression of the ABC-B transporter, T. asperellum T4 was only able to grow normally when glucose was the only carbon source. Compared with the wild-type, the efficiency of (GlcNAc)2 by the overexpression strain evidently increased, along with the activity level of ECH42. In conclusion, one of the functions of the ABC-B transporter in T. asperellum is the uptake and transport of (GlcNAc)2 into cells, and chitobiose is a strong inducer of ECH42 in T. asperellum T4.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Quitinases/metabolismo , Dissacarídeos/metabolismo , Trichoderma/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Transporte Biológico , Meios de Cultura/química , Escherichia coli/genética , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Genes Fúngicos/genética , Polissacarídeos/metabolismo , Protoplastos , Trichoderma/genética , Trichoderma/crescimento & desenvolvimento
10.
BMC Genomics ; 20(1): 430, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-31138126

RESUMO

BACKGROUND: The white rot fungus Phlebia radiata, a type species of the genus Phlebia, is an efficient decomposer of plant cell wall polysaccharides, modifier of softwood and hardwood lignin, and is able to produce ethanol from various waste lignocellulose substrates. Thus, P. radiata is a promising organism for biotechnological applications aiming at sustainable utilization of plant biomass. Here we report the genome sequence of P. radiata isolate 79 originally isolated from decayed alder wood in South Finland. To better understand the evolution of wood decay mechanisms in this fungus and the Polyporales phlebioid clade, gene content and clustering of genes encoding specific carbohydrate-active enzymes (CAZymes) in seven closely related fungal species was investigated. In addition, other genes encoding proteins reflecting the fungal lifestyle including peptidases, transporters, small secreted proteins and genes involved in secondary metabolism were identified in the genome assembly of P. radiata. RESULTS: The PACBio sequenced nuclear genome of P. radiata was assembled to 93 contigs with 72X sequencing coverage and annotated, revealing a dense genome of 40.4 Mbp with approximately 14 082 predicted protein-coding genes. According to functional annotation, the genome harbors 209 glycoside hydrolase, 27 carbohydrate esterase, 8 polysaccharide lyase, and over 70 auxiliary redox enzyme-encoding genes. Comparisons with the genomes of other phlebioid fungi revealed shared and specific properties among the species with seemingly similar saprobic wood-decay lifestyles. Clustering of especially GH10 and AA9 enzyme-encoding genes according to genomic localization was discovered to be conserved among the phlebioid species. In P. radiata genome, a rich repertoire of genes involved in the production of secondary metabolites was recognized. In addition, 49 genes encoding predicted ABC proteins were identified in P. radiata genome together with 336 genes encoding peptidases, and 430 genes encoding small secreted proteins. CONCLUSIONS: The genome assembly of P. radiata contains wide array of carbohydrate polymer attacking CAZyme and oxidoreductase genes in a composition identifiable for phlebioid white rot lifestyle in wood decomposition, and may thus serve as reference for further studies. Comparative genomics also contributed to enlightening fungal decay mechanisms in conversion and cycling of recalcitrant organic carbon in the forest ecosystems.


Assuntos
Genoma Fúngico , Lignina/metabolismo , Polyporales/genética , Transportadores de Cassetes de Ligação de ATP/genética , Metabolismo dos Carboidratos , Celulose/metabolismo , Genômica , Pectinas/metabolismo , Peptídeo Hidrolases/genética , Polyporales/enzimologia , Polissacarídeos/metabolismo , Metabolismo Secundário/genética
11.
Cell Mol Life Sci ; 76(20): 4131-4144, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31053883

RESUMO

ABCB6 belongs to the family of ATP-binding cassette (ABC) transporters, which transport various molecules across extra- and intra-cellular membranes, bearing significant impact on human disease and pharmacology. Although mutations in the ABCB6 gene have been linked to a variety of pathophysiological conditions ranging from transfusion incompatibility to pigmentation defects, its precise cellular localization and function is not understood. In particular, the intracellular localization of ABCB6 has been a matter of debate, with conflicting reports suggesting mitochondrial or endolysosomal expression. ABCB6 shows significant sequence identity to HMT-1 (heavy metal tolerance factor 1) proteins, whose evolutionarily conserved role is to confer tolerance to heavy metals through the intracellular sequestration of metal complexes. Here, we show that the cadmium-sensitive phenotype of Schizosaccharomyces pombe and Caenorhabditis elegans strains defective for HMT-1 is rescued by the human ABCB6 protein. Overexpression of ABCB6 conferred tolerance to cadmium and As(III) (As2O3), but not to As(V) (Na2HAsO4), Sb(V), Hg(II), or Zn(II). Inactivating mutations of ABCB6 abolished vacuolar sequestration of cadmium, effectively suppressing the cadmium tolerance phenotype. Modulation of ABCB6 expression levels in human glioblastoma cells resulted in a concomitant change in cadmium sensitivity. Our findings reveal ABCB6 as a functional homologue of the HMT-1 proteins, linking endolysosomal ABCB6 to the highly conserved mechanism of intracellular cadmium detoxification.


Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Cádmio/toxicidade , Proteínas de Caenorhabditis elegans/genética , Inativação Metabólica/genética , Poluentes Químicos da Água/toxicidade , Transportadores de Cassetes de Ligação de ATP/deficiência , Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Antimônio/toxicidade , Arseniatos/toxicidade , Trióxido de Arsênio/toxicidade , Cádmio/metabolismo , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Linhagem Celular Tumoral , Sequência Conservada , Expressão Gênica , Teste de Complementação Genética , Células HeLa , Humanos , Mercúrio/toxicidade , Mutação , Neurônios/citologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Schizosaccharomyces/efeitos dos fármacos , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Vacúolos/efeitos dos fármacos , Vacúolos/metabolismo , Poluentes Químicos da Água/metabolismo , Zinco/toxicidade
12.
MBio ; 10(3)2019 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-31088929

RESUMO

Paramyxoviruses and pneumoviruses have similar life cycles and share the respiratory tract as a point of entry. In comparative genome-scale siRNA screens with wild-type-derived measles, mumps, and respiratory syncytial viruses in A549 cells, a human lung adenocarcinoma cell line, we identified vesicular transport, RNA processing pathways, and translation as the top pathways required by all three viruses. As the top hit in the translation pathway, ABCE1, a member of the ATP-binding cassette transporters, was chosen for further study. We found that ABCE1 supports replication of all three viruses, confirming its importance for viruses of both families. More detailed characterization revealed that ABCE1 is specifically required for efficient viral but not general cellular protein synthesis, indicating that paramyxoviral and pneumoviral mRNAs exploit specific translation mechanisms. In addition to providing a novel overview of cellular proteins and pathways that impact these important pathogens, this study highlights the role of ABCE1 as a host factor required for efficient paramyxovirus and pneumovirus translation.IMPORTANCE The Paramyxoviridae and Pneumoviridae families include important human and animal pathogens. To identify common host factors, we performed genome-scale siRNA screens with wild-type-derived measles, mumps, and respiratory syncytial viruses in the same cell line. A comparative bioinformatics analysis yielded different members of the coatomer complex I, translation factors ABCE1 and eIF3A, and several RNA binding proteins as cellular proteins with proviral activity for all three viruses. A more detailed characterization of ABCE1 revealed its essential role for viral protein synthesis. Taken together, these data sets provide new insight into the interactions between paramyxoviruses and pneumoviruses and host cell proteins and constitute a starting point for the development of broadly effective antivirals.


Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Interações entre Hospedeiro e Microrganismos/genética , Paramyxoviridae/patogenicidade , Pneumovirus/patogenicidade , Células A549 , Biologia Computacional , Expressão Gênica , Humanos , RNA Mensageiro , RNA Interferente Pequeno , Proteínas de Ligação a RNA/genética
14.
Nat Commun ; 10(1): 2260, 2019 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-31113958

RESUMO

ABC exporters harness the energy of ATP to pump substrates across membranes. Extracellular gate opening and closure are key steps of the transport cycle, but the underlying mechanism is poorly understood. Here, we generated a synthetic single domain antibody (sybody) that recognizes the heterodimeric ABC exporter TM287/288 exclusively in the presence of ATP, which was essential to solve a 3.2 Å crystal structure of the outward-facing transporter. The sybody binds to an extracellular wing and strongly inhibits ATPase activity by shifting the transporter's conformational equilibrium towards the outward-facing state, as shown by double electron-electron resonance (DEER). Mutations that facilitate extracellular gate opening result in a comparable equilibrium shift and strongly reduce ATPase activity and drug transport. Using the sybody as conformational probe, we demonstrate that efficient extracellular gate closure is required to dissociate the NBD dimer after ATP hydrolysis to reset the transporter back to its inward-facing state.


Assuntos
Transportadores de Cassetes de Ligação de ATP/química , Proteínas de Bactérias/química , Simulação de Dinâmica Molecular , Domínio AAA/genética , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/imunologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Espectroscopia de Ressonância de Spin Eletrônica , Mutação , Multimerização Proteica , Anticorpos de Domínio Único/química , Anticorpos de Domínio Único/imunologia , Thermotoga maritima
15.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 35(2): 134-139, 2019 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-30975277

RESUMO

Objective To explore the relationship between the drug resistance gene ATP binding cassette sub-family B member 4 (abcb4) in zebrafish and Wnt/ß-catenin signaling pathway. Methods Wild-type zebrafish and transgenic zebrafish were set in the blank control group, doxorubicin treatment group, vinblastine treatment group, gefitinib treatment group, doxorubicin combined with gefitinib treatment group, and vinblastine combined with gefitinib treatment group. The 100 embryos of each group were treated with drugs until the 5th day, and 50 zebrafish juveniles were tested on the 5th day in each group. The drug resistance of wild-type zebrafish was tested by rhodamine 123 experiment. The fluorescence intensity of transgenic zebrafish was tested by microplate reader, and the fluorescence distribution was tested by living cell workstation. The protein levels of transgenic zebrafish ß-catenin, GSK-3ß, ABCB4 and enhanced green fluorescent protein (EGFP) were tested by Western blot analysis. Results Rhodamine 123 experiments proved that there was drug resistance in zebrafish when treated with doxorubicin and vinblastine. Compared with the blank group, the EGFP fluorescence intensity increased in the transgenic zebrafish when treated with doxorubicin and vinblastine. Western blot assay showed the accumulation of ß-catenin accompanied by the increase of EGFP and ABCB4 proteins in the transgenic zebrafish exposed to adriamycin and vincristine. Conclusion The Wnt/ß-catenin signaling pathway in zebrafish is involved in the activation and drug resistance of zebrafish abcb4 gene.


Assuntos
Resistência a Medicamentos , Via de Sinalização Wnt , Proteínas de Peixe-Zebra , Peixe-Zebra , beta Catenina , Transportadores de Cassetes de Ligação de ATP/genética , Animais , Animais Geneticamente Modificados , Antineoplásicos/farmacologia , Resistência a Medicamentos/genética , Embrião não Mamífero/efeitos dos fármacos , Via de Sinalização Wnt/fisiologia , Proteínas de Peixe-Zebra/genética , beta Catenina/metabolismo
16.
Doc Ophthalmol ; 139(1): 45-57, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30945053

RESUMO

PURPOSE: The aim of this study was to examine the ophthalmological characteristics and genotypes of patients with congenital retinal pathologies, who display a bull's-eye maculopathy in the fundus, along with a negative scotopic electroretinogram. METHODS: We analysed the results of five patients showing both a bull's-eye maculopathy, as well as a negative scotopic ERG evoked by a bright flash. Their median age was 39 years (range 11-63 years): three males and two females. All underwent a comprehensive examination with determination of distant visual acuity (ETDRS) and recording of the full-field ERG (scotopic and photopic). Fundus, OCT, and FAF images were obtained, the kinetic visual field was determined, and colour vision (D-15) was tested in most patients. Targeted gene panel sequencing was performed on peripheral blood. RESULTS: One patient carried a homozygous ABCA4 mutation and an additional heterozygous variant in CRX. Two of the five patients were shown to have a heterozygous mutation in the CRX gene, one of whom had an additional heterozygous ABCA4 mutation. Two patients had the common heterozygous mutation c.2413G>A;p.Arg838His in GUCY2D. In all of the patients, there was a reduction in the amplitude of the b-wave with a regular a-wave amplitude in the scotopic bright-flash ERG. CONCLUSIONS: The five patients with bull's-eye maculopathy along with a negative ERG had differing genotypes. Mutations were found in the CRX gene (2 patients), the ABCA4 gene (1 patient), and the GUCY2D gene (2 patients).


Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Guanilato Ciclase/genética , Proteínas de Homeodomínio/genética , Degeneração Macular/genética , Degeneração Macular/fisiopatologia , Mutação , Receptores de Superfície Celular/genética , Retina/fisiopatologia , Transativadores/genética , Adulto , Criança , Análise Mutacional de DNA , Eletrorretinografia , Feminino , Angiofluoresceinografia , Humanos , Degeneração Macular/diagnóstico , Masculino , Pessoa de Meia-Idade , Visão Noturna/fisiologia , Estimulação Luminosa , Acuidade Visual/fisiologia , Adulto Jovem
17.
Appl Microbiol Biotechnol ; 103(10): 4167-4175, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30953120

RESUMO

Rhodococcus erythropolis N9T-4, which is an extremely oligotrophic bacterium, can survive in a completely inorganic medium with no additional carbon source. This bacterium utilizes atmospheric CO2, but does not require any additional energy source such as light and hydrogen gas, required by autotrophic microorganisms. However, its CO2 fixation and energy-acquisition systems in the oligotrophic growth remain unrevealed. We expected N9T-4 to have the transporter(s) that imports essential compound(s) for its oligotrophic growth. Three putative ATP-binding cassette (ABC) transporters were found to be highly upregulated under oligotrophic conditions. We constructed the gene-deletion mutants of a gene encoding the substrate-binding protein for each ABC transporter (∆sbp1, ∆sbp2, and ∆sbp3). Among these mutants, ∆sbp1 showed growth defects on oligotrophic medium without carbon source. We examined the growth of the mutants on the oligotrophic medium containing 1% trehalose as a sole carbon source. The results exhibited worse growth of ∆sbp3 than that of the control strain (∆ligD), whereas intracellular trehalose content of all mutants decreased compared with that of ∆ligD. It was reported that trehalose functions as the mycolate carrier to the arabinogalactan layer in the cell wall of Mycobacterium tuberculosis. Transmission electron microscopic analysis of ∆sbp1 cells showed that an outermost envelope of the ∆sbp1 cell diminished, which was expected to be mycolate layer. From these results, we suggest that the same trehalose-recycling system as that in a Mycobacterium cell functions in the oligotrophic growth of N9T-4, and the ABC transporter comprising Sbp1 as the substrate-binding protein is strongly involved in the oligotrophic growth of N9T-4.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Dióxido de Carbono/metabolismo , Rhodococcus/crescimento & desenvolvimento , Rhodococcus/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Membrana Celular/ultraestrutura , Meios de Cultura/química , Metabolismo Energético , Deleção de Genes , Regulação Bacteriana da Expressão Gênica , Microscopia Eletrônica de Transmissão , Ácidos Micólicos/metabolismo , Rhodococcus/genética , Rhodococcus/ultraestrutura
18.
Gene ; 707: 109-116, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-30943440

RESUMO

Ecdysone is involved in regulation of embryonic diapause in the silkworm, Bombyx mori. However, its mechanism still remains unclear. To explore the role of ecdysteroidogenic pathway (EP) genes in diapause process of bivoltine B. mori, the eggs of "Qiufeng", a bivoltine strain, were used as the study materials and arranged into diapause eggs producers (DEPs) and non-diapause eggs producers (NDEPs), respectively. The differential expression of EP genes between two groups was analysed during the early pupal stage. The expression of Shadow was significantly increased in the NDEPs in day-3 pupae and reached the peak simultaneously, indicating that Shadow was in coincidence with diapause process. To validate this hypothesis, a repression of Shadow by RNA interference was performed in day-2 pupae of NDEPs. The expression of Shadow was downregulated by RNAi, and ßFtz-F1, a downstream gene of EP, was also decreased. Furthermore, the genes encoding the kynurenine-synthetase were upregulated in the ovary, and Brown, AdenoK which link Shadow to the kynurenine-synthase gene were also upregulated in the fat body. The progeny eggs appeared a light purple colour at 48 h after oviposition, revealing a certain tendency to diapause. We speculate that inhibition of Shadow upregulates 3-hydroxy-kynurenine synthesis by increasing the expression of Brown and AdenoK. In addition, Shadow was cloned, and expressed in E. coli for further functional study of Shadow protein. Our study provided insight into the role of EP genes in the process of diapause of B. mori.


Assuntos
Bombyx/fisiologia , Sistema Enzimático do Citocromo P-450/genética , Diapausa de Inseto , Ecdisteroides/biossíntese , Perfilação da Expressão Gênica/métodos , Genes de Insetos/fisiologia , Transportadores de Cassetes de Ligação de ATP/genética , Tecido Adiposo/metabolismo , Animais , Bombyx/classificação , Bombyx/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Ecdisteroides/genética , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Redes Reguladoras de Genes , Proteínas de Insetos/genética , Masculino , Ovário/metabolismo , Transdução de Sinais , Distribuição Tecidual
19.
Appl Microbiol Biotechnol ; 103(11): 4539-4548, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30997553

RESUMO

The MtrA-MtrB two-component regulatory system is highly conserved in Actinobacteria and plays crucial roles in cell cycle progression, cell morphology, antibiotic resistance, and osmoprotection. Previously, we revealed that the MtrA protein of Saccharopolyspora erythraea E3 strain (a high erythromycin-producing strain) had a two amino acid (H197 and V198) deletion in the DNA recognition helices of the C-terminal domain compared to the wild type S. erythraea strain NRRL2338. Here, we identified mepA (encoding a membrane protein related to metalloendopeptidases) as an MtrA target gene, and found that deleting the two amino acids in MtrA (MtrAdel) resulted in the loss of its DNA-binding activity for the mepA gene. The mutant MtrAdel lost its regulatory activity and affected various physiological functions consistent with mtrA deletion, including increased erythromycin biosynthesis, enhanced antibiotic resistance, deregulated osmoprotection, and improved transport of substances. The introduction of the wild type mtrA gene into the S. erythraea E3 strain with the mtrAdel gene decreased the erythromycin yield by approximately 50%, confirming that MtrA repressed erythromycin production. These findings demonstrate that MtrA is an important pleiotropic regulator of erythromycin biosynthesis, antibiotic resistance, osmoprotection, and substance transport in S. erythraea and provide new insights for improving erythromycin production. Future studies linking the molecular effects of MtrA to these phenotypes will improve our understanding of the MtrA-MtrB two-component regulatory system in Actinobacteria.


Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Antibacterianos/biossíntese , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Eritromicina/biossíntese , Saccharopolyspora/enzimologia , Saccharopolyspora/metabolismo , Deleção de Sequência , Transporte Biológico , Farmacorresistência Bacteriana , Regulação Bacteriana da Expressão Gênica , Teste de Complementação Genética , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Fenótipo , Saccharopolyspora/crescimento & desenvolvimento
20.
Chem Biol Interact ; 305: 98-104, 2019 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-30929998

RESUMO

Multidrug resistance remains a major challenge in the chemotherapy of breast cancer. Guajadial, a natural meroterpenoid, has been found to possess anti-tumor activity. However, the role of guajadial in drug resistance has not been investigated. The aim of this study was to evaluate the effect of guajadial on drug resistance in drug-resistant breast cancer cells. Cell viability was measured by MTT assay, and the IC50 values were calculated. The expression of ATP-binding cassette (ABC) transporters including P-glycoprotein (P-gp) and the breast cancer resistance protein (BCRP) was detected by qRT-PCR and western blot. The expression of Akt, p-Akt, p70S6K, and p-p70S6K was determined by western blot. We found that guajadial significantly inhibited cell viability of parental non-resistant cell line MCF-7, adriamycin (ADR)-resistant cell line MCF-7/ADR, and paclitaxel (PTX)-resistant cell line MCF-7/PTX in a dose-dependent manner. Guajadial enhanced ADR and PTX sensitivity of MCF-7/ADR and MCF-7/PTX cells, and inhibited the expression of P-gp and BCRP. Guajadial treatment resulted in an inactivation of PI3K/Akt pathway in drug-resistant MCF-7 cells. In conclusion, guajadial acted as an inhibitor of drug resistance, which might be mediated by the inhibition of ABC transporter expression and PI3K/Akt pathway in drug-resistant breast cancer cells. These findings suggested that guajadial treatment might be a new approach to overcome the drug resistance in the chemotherapy of breast cancer.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Terpenos/farmacologia , Transportadores de Cassetes de Ligação de ATP/antagonistas & inibidores , Transportadores de Cassetes de Ligação de ATP/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Sobrevivência Celular/efeitos dos fármacos , Doxorrubicina/farmacologia , Feminino , Humanos , Células MCF-7 , Paclitaxel/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Quinases S6 Ribossômicas 70-kDa/genética , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo
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