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PURPOSE: This prospective study aims to evaluate the value of [18F]AlF-NOTA-fibroblast activation protein inhibitor (FAPI)-04 positron emission tomography-computed tomography (PET/CT) in predicting molecular subtypes of breast cancer. METHODS: The study consecutively recruited patients suspected of having breast cancer from a single center who were prospectively enrolled from July 2023 to May 2024 and underwent [18F]AlF-NOTA-FAPI-04 PET/CT. This study compared the differences in tracer uptake among breast cancers with different adverse prognostic factors and molecular subtypes. The classification performance for each molecular subtype of breast cancer was assessed using a receiver operating characteristic (ROC) curve. RESULTS: Fifty-three participants (mean age, 51 ± 11 years; 52 females) were evaluated. Breast cancer lesions with adverse prognostic factors showed higher tracer uptake. The five different molecular subtypes exhibited varying levels of uptake. The luminal A and luminal B (HER2-negative) subtypes had relatively low uptake, while the luminal B (HER2-positive), HER2-positive, and triple-negative subtypes had relatively high uptake. ROC analysis identified the max standardized uptake value (SUVmax) as a significant classifier (AUC = 0.912, P = 0.0005) for the luminal A subtype, with 100% sensitivity and 83% specificity. For predicting the luminal B (HER2-negative) subtype, SUVmax had an AUC of 0.770 (P = 0.0015). SUVmax, with an AUC of 0.781 (P = 0.003), was used to identify the triple-negative subtype tumors, resulting in a sensitivity of 100% and specificity of 51%. Lastly, the ROC curve showed the cut-off 15.40 (AUC = 0.921, P < 0.0001) could classify luminal A & luminal B (HER2-negative), and luminal B (HER2-positive) & HER2-positive & triple-negative, yielding a sensitivity of 94% and specificity of 79%. CONCLUSION: The uptake of [18F]AlF-NOTA-FAPI-04 is significantly correlated with the molecular subtypes of breast cancer, and [18F]AlF-NOTA-FAPI-04 PET/CT is a potential tool for noninvasive identification of luminal A subtypes and guidance of FAP-targeted therapies.
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Objective: Hypothyroidism, characterized by reduced thyroid hormone levels, and endometrial cancer, a prevalent gynecological malignancy, have been suggested to have a potential association in previous observational studies. However, the causal relationship between them remains uncertain. This study aimed to investigate the causal relationship between hypothyroidism and endometrial cancer using a bilateral Mendelian randomization approach. Methods: A bidirectional two-sample Mendelian randomization study was conducted using summary statistics from genome-wide association studies to identify genetic variants associated with hypothyroidism and endometrial cancer. The inverse variance weighting method was used as the main analysis, and sensitivity analyses were conducted to validate the MR results. Results: The results of our analysis did not support a causal effect of hypothyroidism (OR: 0.93, p=0.08) or autoimmune hypothyroidism (OR: 0.98, p=0.39) on endometrial cancer risk. In the reverse MR analysis, we did not find a significant causal effect of endometrial cancer on hypothyroidism (OR: 0.96, p=0.75) or autoimmune hypothyroidism (OR: 0.92, p=0.50). Based on subgroup analysis by pathological subtypes of endometrial cancer, the above findings were further substantiated (all p-value >0.05). Conclusions: Our Mendelian randomization analysis suggests a lack of causal association between hypothyroidism and endometrial cancer. To gain a deeper understanding of this association, it is essential to conduct large-scale randomized controlled trials in the future to validate our findings.
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Neoplasias do Endométrio , Estudo de Associação Genômica Ampla , Hipotireoidismo , Análise da Randomização Mendeliana , Humanos , Feminino , Neoplasias do Endométrio/genética , Neoplasias do Endométrio/epidemiologia , Hipotireoidismo/genética , Hipotireoidismo/epidemiologia , Polimorfismo de Nucleotídeo Único , Fatores de RiscoRESUMO
OBJECTIVE: Min pigs are a unique genetic resource among local pig breeds in China. They have more excellent characteristics in cold and stress resistance, good meat quality, and a high reproductive rate. However, the genetic structure and driving factors remain unclear in the nucleus herd. In this study, the genetic diversity of Min pigs was studied to reveal the formation mechanism of its unique genetic structure. We hope to protect and develop the genetic resources of Min pigs. METHODS: We analyzed different types of genes to identify the genetic structure and gene introgression pattern of Min pigs. The nuclear DNA dataset includes information on 21 microsatellite loci and 6 Y-chromosome genes, and the mitochondrial D-loop gene is selected to represent maternal lineages. The above genes are all from the nucleus herd of Min pigs. RESULTS: The results of genetic structure identification and analysis of potential exogenous gene introgression patterns indicate that the nucleus herd of Min pigs maintains a high level of genetic diversity (polymorphism information content = 0.713, expected heterozygosity = 0.662, observed heterozygosity = 0.612). Compared with other Asian pig breeds, the formation of Min pig breeds is more special. Gene introgression from European pig breeds to Min pigs has occurred, which is characterized by complete introgression of paternal genes and incomplete introgression of maternal genes. CONCLUSION: Gene introgression caused by cross-breeding is not the main factor leading to the formation of the current genetic structure of Min pigs, but this process has increased the level of genetic diversity in the nucleus herd. Compared with the influence of gene introgression, our research suggest that artificial selection and environmental adaptive evolution make Min pigs form unique genetic characteristics.
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Variação Genética , Genética Populacional , Suínos/genética , Animais , Polimorfismo Genético , Mitocôndrias/genética , HeterozigotoRESUMO
Although emerging evidence indicates that alterations in proteins within nuclear compartments elicit changes in chromosomal architecture and differentiation, the underlying mechanisms are not well understood. Here we investigate the direct role of the abundant nuclear complex protein Matrin3 (Matr3) in chromatin architecture and development in the context of myogenesis. Using an acute targeted protein degradation platform (dTAG-Matr3), we reveal the dynamics of development-related chromatin reorganization. High-throughput chromosome conformation capture (Hi-C) experiments revealed substantial chromatin loop rearrangements soon after Matr3 depletion. Notably, YY1 binding was detected, accompanied by the emergence of novel YY1-mediated enhancer-promoter loops, which occurred concurrently with changes in histone modifications and chromatin-level binding patterns. Changes in chromatin occupancy by Matr3 also correlated with these alterations. Overall, our results suggest that Matr3 mediates differentiation through stabilizing chromatin accessibility and chromatin loop-domain interactions, and highlight a conserved and direct role for Matr3 in maintenance of chromosomal architecture.
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Cromatina , Elementos Facilitadores Genéticos , Proteínas Associadas à Matriz Nuclear , Proteínas de Ligação a RNA , Núcleo Celular , Cromatina/química , Cromatina/genética , Cromatina/metabolismo , Cromossomos , Regiões Promotoras Genéticas/genética , Humanos , Proteínas de Ligação a RNA/metabolismo , Proteínas Associadas à Matriz Nuclear/metabolismoRESUMO
PURPOSE: Radiation-induced lung injury (RILI) is a severe side effect of radiotherapy (RT) for thoracic malignancies and we currently lack established methods for the early detection of RILI. In this study, we synthesized a new tracer, [18F]AlF-NOTA-QHY-04, targeting C-X-C-chemokine-receptor-type-4 (CXCR4) and investigated its feasibility to detect RILI. METHODS: An RILI rat model was constructed and scanned with [18F]AlF-NOTA-QHY-04 PET/CT and [18F]FDG PET/CT periodically after RT. Dynamic, blocking, autoradiography, and histopathological studies were performed on the day of peak uptake. Fourteen patients with radiation pneumonia, developed during or after thoracic RT, were subjected to PET scan using [18F]AlF-NOTA-QHY-04. RESULTS: The yield of [18F]AlF-NOTA-QHY-04 was 28.5-43.2%, and the specific activity was 27-33 GBq/µmol. [18F]AlF-NOTA-QHY-04 was mainly excreted through the kidney. Significant increased [18F]AlF-NOTA-QHY-04 uptake in the irradiated lung compared with that in the normal lung in the RILI model was observed on day 6 post-RT and peaked on day 14 post-RT, whereas no apparent uptake of [18F]FDG was shown on days 7 and 15 post-RT. MicroCT imaging did not show pneumonia until 42 days post-RT. Significant intense [18F]AlF-NOTA-QHY-04 uptake was confirmed by autoradiography. Immunofluorescence staining demonstrated expression of CXCR4 was significantly increased in the irradiated lung tissue, which correlated with results obtained from hematoxylin-eosin and Masson's trichrome staining. In 14 patients with radiation pneumonia, maximum standardized uptake values (SUVmax) were significantly higher in the irradiated lung compared with those in the normal lung. SUVmax of patients with grade 2 RILI was significantly higher than that of patients with grade 1 RILI. CONCLUSION: This study indicated that [18F]AlF-NOTA-QHY-04 PET/CT imaging can detect RILI non-invasively and earlier than [18F]FDG PET/CT in a rat model. Clinical studies verified its feasibility, suggesting the clinical potential of [18F]AlF-NOTA-QHY-04 as a PET/CT tracer for early monitoring of RILI.
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Lesão Pulmonar , Lesões por Radiação , Pneumonite por Radiação , Humanos , Ratos , Animais , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Fluordesoxiglucose F18 , Lesão Pulmonar/diagnóstico por imagem , Lesão Pulmonar/etiologia , Tomografia por Emissão de Pósitrons/métodos , Pulmão/diagnóstico por imagem , Receptores CXCR4RESUMO
The droplet size, zeta potential, interface protein adsorption rate, physical stability and microrheological properties of high-pressure-homogenization (HPH)-modified, dual-protein-based whey-soy (whey protein isolate-soy protein isolate) emulsions containing different oil phase concentrations (5%, 10% and 15%; w/w) were compared in this paper. The in vitro digestion characteristics and storage stability of the dual-protein emulsions before and after HPH treatment were also explored. The results show that with an increase in the oil phase concentration, the droplet size and interface protein adsorption rate of the untreated dual-protein emulsions increased, while the absolute value of the zeta potential decreased. When the oil phase concentration was 10% (w/w), HPH treatment could significantly reduce the droplet size of the dual-protein emulsion, increase the interface protein adsorption rate, and improve the elasticity of the emulsion. Compared with other oil phase concentrations, the physical stability of the dual-protein emulsion containing a 10% (w/w) oil phase concentration was the best, so the in vitro digestion characteristics and storage stability of the emulsions were studied. Compared with the control group, the droplet size of the HPH-modified dual-protein emulsion was significantly reduced after gastrointestinal digestion, and the in vitro digestibility and release of free amino groups both significantly increased. The storage stability results show that the HPH-modified dual-protein emulsion showed good stability under different storage methods, and the storage stability of the steam-sterilized dual-protein emulsion stored at room temperature was the best. These results provide a theoretical basis for the development of new nutritional and healthy dual-protein liquid products.
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It has been proven that high-pressure homogenization (HPH) could improve the functional properties of proteins by modifying their structure. This study researched the effect of HPH on the structural and functional properties of whey-soy dual-protein (Soy Protein Isolation-Whey Protein Isolation, SPI-WPI). Different protein solution samples were treated with HPH at 30, 60, 90, 120 and 150 MPa, and the structure changed under different pressures was analyzed by measuring particle size, zeta potential, Fourier infrared spectrum (FTIR), fluorescence spectrum and scanning electron microscope (SEM). The results showed that HPH significantly reduced the particle size of SPI-WPI, changed the secondary and tertiary structures and improved the hydrophobic interaction between molecules. In addition, HPH significantly improved the solubility and emulsification of all proteins, and the improvement effect on SPI-WPI was significantly better than SPI and WPI. It was found that SPI-WPI treated with 60 MPa had the best physicochemical properties. Secondly, we researched the effect of HPH by 60 MPa on the emulsion properties of SPI-WPI. In this study, the SPI-WPI had the lowest surface tension compared to a single protein after HPH treatment. The emulsion droplet size was obviously decreased, and the elastic properties and physical stability of SPI-WPI emulsion were significantly enhanced. In conclusion, this study will provide a theoretical basis for the application of HPH in modifying the structure of dual-protein to improve its development and utilization in liquid specialty food.
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The extensive utilization of iron oxide nanoparticles in medical and life science domains has led to a substantial rise in both occupational and public exposure to these particles. The potential toxicity of nanoparticles to living organisms, their impact on the environment, and the associated risks to human health have garnered significant attention and come to be a prominent area in contemporary research. The comprehension of the potential toxicity of nanoparticles has emerged as a crucial concern to safeguard human health and facilitate the secure advancement of nanotechnology. As nanocarriers and targeting agents, the biocompatibility of them determines the use scope and application prospects, meanwhile surface modification becomes an important measure to improve the biocompatibility. Three different types of iron oxide nanoparticles (Fe3O4, Fe3O4@PDA and MSCM-Fe3O4@PDA) were injected into mice through the tail veins. The acute neurotoxicity of them in mice was evaluated by measuring the levels of autophagy and apoptosis in the brain tissues. Our data revealed that iron oxide nanoparticles could cause nervous system damage by regulating the ASK1/JNK signaling pathway. Apoptosis and autophagy may play potential roles in this process. Exposure to combined surface functionalization of mesenchymal stem cell membrane and polydopamine showed the neuroprotective effect and may alleviate brain nervous system disorders.
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Sistema de Sinalização das MAP Quinases , Nanopartículas , Camundongos , Humanos , Animais , Autofagia , ApoptoseRESUMO
Hematopoiesis changes over life to meet the demands of maturation and aging. Here, we find that the definitive hematopoietic stem and progenitor cell (HSPC) compartment is remodeled from gestation into adulthood, a process regulated by the heterochronic Lin28b/let-7 axis. Native fetal and neonatal HSPCs distribute with a pro-lymphoid/erythroid bias with a shift toward myeloid output in adulthood. By mining transcriptomic data comparing juvenile and adult HSPCs and reconstructing coordinately activated gene regulatory networks, we uncover the Polycomb repressor complex 1 (PRC1) component Cbx2 as an effector of Lin28b/let-7's control of hematopoietic maturation. We find that juvenile Cbx2-/- hematopoietic tissues show impairment of B-lymphopoiesis, a precocious adult-like myeloid bias, and that Cbx2/PRC1 regulates developmental timing of expression of key hematopoietic transcription factors. These findings define a mechanism of regulation of HSPC output via chromatin modification as a function of age with potential impact on age-biased pediatric and adult blood disorders.
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Hematopoese , Células-Tronco Hematopoéticas , MicroRNAs , Complexo Repressor Polycomb 1 , Proteínas de Ligação a RNA , Adulto , Animais , Criança , Redes Reguladoras de Genes , Hematopoese/genética , Células-Tronco Hematopoéticas/metabolismo , Humanos , Recém-Nascido , Linfopoese , Camundongos , Complexo Repressor Polycomb 1/genética , Complexo Repressor Polycomb 1/metabolismo , Proteínas do Grupo Polycomb/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismoRESUMO
Acute myeloid leukemia with KMT2A (MLL) rearrangements is characterized by specific patterns of gene expression and enhancer architecture, implying unique core transcriptional regulatory circuitry. Here, we identified the transcription factors MEF2D and IRF8 as selective transcriptional dependencies of KMT2A-rearranged AML, where MEF2D displays partially redundant functions with its paralog, MEF2C. Rapid transcription factor degradation followed by measurements of genome-wide transcription rates and superresolution microscopy revealed that MEF2D and IRF8 form a distinct core regulatory module with a narrow direct transcriptional program that includes activation of the key oncogenes MYC, HOXA9, and BCL2. Our study illustrates a mechanism of context-specific transcriptional addiction whereby a specific AML subclass depends on a highly specialized core regulatory module to directly enforce expression of common leukemia oncogenes.
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Leucemia Mieloide Aguda , Proteína de Leucina Linfoide-Mieloide , Rearranjo Gênico , Humanos , Fatores Reguladores de Interferon/genética , Fatores Reguladores de Interferon/metabolismo , Leucemia Mieloide Aguda/genética , Proteína de Leucina Linfoide-Mieloide/genética , Proteína de Leucina Linfoide-Mieloide/metabolismo , Oncogenes/genéticaRESUMO
This study takes the Nanfei River as an example, using a hydrodynamic and water quality model based on MIKE11 to predict the effect of graphene photocatalysis on urban rivers. The effect of water quality improvement in the Nanfei River was simulated under three different scenarios (treatment plant upgrade, use of graphene photocatalytic oxidation technology, and a combination of both), and the results showed that implementing a graphene photocatalytic network could significantly improve water quality. The improvement of sewage treatment plants can also improve the water quality to a certain extent, improving the sewage treatment plants alone is insufficient. The combination of graphene photocatalytic oxidation technology with methods to improve wastewater treatment plants produced the best improvement in water quality. The required water quality was achieved, as the total phosphorus content throughout the year was below the limit, and the ammonia nitrogen standard was met 95.89% of the time in the State-controlled section (Shikou section). Therefore, this study provides a new, feasible method for treating the water of polluted rivers.
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Grafite , Poluentes Químicos da Água , China , Monitoramento Ambiental , Nitrogênio/análise , Rios , Esgotos , Poluentes Químicos da Água/análise , Qualidade da ÁguaRESUMO
Precise control of gene expression during differentiation relies on the interplay of chromatin and nuclear structure. Despite an established contribution of nuclear membrane proteins to developmental gene regulation, little is known regarding the role of inner nuclear proteins. Here we demonstrate that loss of the nuclear scaffolding protein Matrin-3 (Matr3) in erythroid cells leads to morphological and gene expression changes characteristic of accelerated maturation, as well as broad alterations in chromatin organization similar to those accompanying differentiation. Matr3 protein interacts with CTCF and the cohesin complex, and its loss perturbs their occupancy at a subset of sites. Destabilization of CTCF and cohesin binding correlates with altered transcription and accelerated differentiation. This association is conserved in embryonic stem cells. Our findings indicate Matr3 negatively affects cell fate transitions and demonstrate that a critical inner nuclear protein impacts occupancy of architectural factors, culminating in broad effects on chromatin organization and cell differentiation.
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Cromatina/química , Leucemia Eritroblástica Aguda/patologia , Proteínas Associadas à Matriz Nuclear/metabolismo , Proteínas de Ligação a RNA/metabolismo , Animais , Fator de Ligação a CCCTC , Proteínas de Ciclo Celular/metabolismo , Diferenciação Celular/fisiologia , Núcleo Celular/genética , Núcleo Celular/metabolismo , Núcleo Celular/ultraestrutura , Cromatina/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Células-Tronco Embrionárias/fisiologia , Células Eritroides/patologia , Leucemia Eritroblástica Aguda/metabolismo , Camundongos Knockout , Proteínas Associadas à Matriz Nuclear/genética , Proteínas de Ligação a RNA/genética , CoesinasRESUMO
Fe3O4 nanoparticles are widely used in the diagnosis and treatment of diseases due to their superparamagnetism, but their toxicity in vivo, which can result in apoptosis or autophagy, cannot be ignored. It has been reported that polydopamine (PDA) modification can reduce the toxicity of Fe3O4 and increase its biocompatibility. However, more research is warranted to further improve the modification method. We therefore developed a new method to coat Fe3O4@PDA nanoparticles with the mesenchymal stem cell membrane (MSCM) and evaluated the toxicity of the modified particles in the lungs of mice. We found that the MSCM modification significantly reduced lung injury induced by Fe3O4 particles in mice. Compared with Fe3O4@PDA nanoparticles, co-modification with MSCM and PDA significantly reduced autophagy and apoptosis in mouse lung tissue, and reduced activation of autophagy mediated by the AMPK-ULK1 pathway axis. Thus, co-modification with MSCM and PDA prevents Fe3O4-induced pulmonary toxicity in mice by inhibiting autophagy, apoptosis, and oxidative stress.
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Adenilato Quinase/metabolismo , Membrana Celular/efeitos dos fármacos , Compostos Férricos/toxicidade , Indóis/farmacologia , Pneumopatias/induzido quimicamente , Células-Tronco Mesenquimais/efeitos dos fármacos , Polímeros/farmacologia , Adenilato Quinase/genética , Animais , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/genética , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/metabolismo , Membrana Celular/fisiologia , Regulação da Expressão Gênica/efeitos dos fármacos , Células-Tronco Mesenquimais/fisiologia , Camundongos , Camundongos Endogâmicos ICR , Estresse Oxidativo/efeitos dos fármacosRESUMO
Pseudorabies virus (PRV) is an important pathogen that threatens the global swine industry. Currently, there is no effective drug that can clinically prevent or treat PRV infections. Isobavachalcone (IBC), a natural chalcone compound derived from Psoralea corylifolia, displays multiple biological activities, such as antibacterial, antifungal, and anticancer activities. Recently, it was found that IBC exhibited antiviral activity against an RNA virus, porcine reproductive and respiratory syndrome virus (PRRSV), in vitro. In the current study, we further demonstrated for the first time that IBC has a strong inhibitory effect on PRV. Through a viral luciferase expression assay, we showed that the inhibition step occurs mainly in the late stage of viral replication. Finally, via a cell-to-cell fusion assay, we demonstrated that IBC inhibits PRV by blocking virus-mediated cell fusion. Thus, IBC may be a candidate for further therapeutic evaluation against PRV infection in vivo.
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Antivirais/farmacologia , Fusão Celular , Chalconas/farmacologia , Herpesvirus Suídeo 1/efeitos dos fármacos , Replicação Viral/efeitos dos fármacos , Animais , Linhagem Celular , Rim/citologia , SuínosRESUMO
Porcine reproductive and respiratory syndrome virus (PRRSV) is a pathogen of great economic significance that impacts the swine industry globally. Since the first report of a porcine reproductive and respiratory syndrome (PRRS) outbreak, tremendous efforts to control this disease, including various national policies and plans incorporating the use of multiple modified live-virus vaccines, have been made. However, PRRSV is still a significant threat to the swine industry, and new variants continually emerge as a result of PRRSV evolution. Several studies have shown that pandemic PRRSV strains have enormous genetic diversity and that commercial vaccines can only provide partial protection against these strains. Therefore, effective anti-PRRSV drugs may be more suitable and reliable for PRRSV control. In this study, we observed that isobavachalcone (IBC), which was first isolated from Psoralea corylifolia, had potent anti-PRRSV activity in vitro. Although many biological activities of IBC have been reported, this is the first report describing the antiviral activity of IBC. Furthermore, after a systematic investigation, we demonstrated that IBC inhibits PRRSV replication at the post-entry stage of PRRSV infection. Thus, IBC may be a candidate for further evaluation as a therapeutic agent against PRRSV infection of swine in vivo.
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Antivirais/farmacologia , Chalconas/farmacologia , Vírus da Síndrome Respiratória e Reprodutiva Suína/efeitos dos fármacos , Replicação Viral/efeitos dos fármacos , Animais , Descoberta de Drogas , Concentração Inibidora 50 , Macrófagos Alveolares/virologia , Síndrome Respiratória e Reprodutiva Suína/tratamento farmacológico , Síndrome Respiratória e Reprodutiva Suína/virologia , Vírus da Síndrome Respiratória e Reprodutiva Suína/fisiologia , Suínos , Internalização do VírusRESUMO
The Drosophila circadian clock keeps time via transcriptional feedback loops. These feedback loops are initiated by CLOCK-CYCLE (CLK-CYC) heterodimers, which activate transcription of genes encoding the feedback repressors PERIOD and TIMELESS. Circadian clocks normally operate in â¼150 brain pacemaker neurons and in many peripheral tissues in the head and body, but can also be induced by expressing CLK in nonclock cells. These ectopic clocks also require cyc, yet CYC expression is restricted to canonical clock cells despite evidence that cyc mRNA is widely expressed. Here we show that CLK binds to and stabilizes CYC in cell culture and in nonclock cells in vivo. Ectopic clocks also require the blue light photoreceptor CRYPTOCHROME (CRY), which is required for both light entrainment and clock function in peripheral tissues. These experiments define the genetic architecture required to initiate circadian clock function in Drosophila, reveal mechanisms governing circadian activator stability that are conserved in perhaps all eukaryotes, and suggest that Clk, cyc, and cry expression is sufficient to drive clock expression in naive cells.
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Fatores de Transcrição ARNTL/química , Animais Geneticamente Modificados/metabolismo , Proteínas CLOCK/metabolismo , Relógios Circadianos , Criptocromos/metabolismo , Proteínas de Drosophila/química , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/fisiologia , Neurônios/fisiologia , Fatores de Transcrição ARNTL/genética , Fatores de Transcrição ARNTL/metabolismo , Animais , Animais Geneticamente Modificados/genética , Proteínas CLOCK/genética , Células Cultivadas , Ritmo Circadiano , Proteínas de Drosophila/genética , Neurônios/citologiaRESUMO
Circadian (â¼24 hr) clocks regulate daily rhythms in physiology, metabolism, and behavior via cell-autonomous transcriptional feedback loops. In Drosophila, the blue-light photoreceptor CRYPTOCHROME (CRY) synchronizes these feedback loops to light:dark cycles by binding to and degrading TIMELESS (TIM) protein. CRY also acts independently of TIM in Drosophila to alter potassium channel conductance in arousal neurons after light exposure, and in many animals CRY acts independently of light to repress rhythmic transcription. CRY expression has been characterized in the Drosophila brain and eyes, but not in peripheral clock and non-clock tissues in the body. To investigate CRY expression and function in body tissues, we generated a GFP-tagged-cry transgene that rescues light-induced behavioral phase resetting in cry03 mutant flies and sensitively reports GFP-CRY expression. In bodies, CRY is detected in clock-containing tissues including Malpighian tubules, where it mediates both light-dependent TIM degradation and clock function. In larval salivary glands, which lack clock function but are amenable to electrophysiological recording, CRY prevents membrane input resistance from falling to low levels in a light-independent manner. The ability of CRY to maintain high input resistance in these non-excitable cells also requires the K+ channel subunits Hyperkinetic, Shaker, and ether-a-go-go. These findings for the first time define CRY expression in Drosophila peripheral tissues and reveal that CRY acts together with K+ channels to maintain passive membrane properties in a non-clock-containing peripheral tissue independent of light.
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Relógios Circadianos/genética , Criptocromos/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/fisiologia , Proteínas do Olho/genética , Luz , Animais , Criptocromos/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Proteínas do Olho/metabolismo , Perfilação da Expressão Gênica , Proteínas de Fluorescência Verde/genética , Larva/genética , Larva/crescimento & desenvolvimento , Larva/fisiologia , Transgenes/genéticaRESUMO
Circadian pacemaker neurons in the Drosophila brain control daily rhythms in locomotor activity. These pacemaker neurons can be subdivided into early or late groups depending on whether rhythms in period (per) and timeless (tim) expression are initiated at the first instar (L1) larval stage or during metamorphosis, respectively. Because CLOCK-CYCLE (CLK-CYC) heterodimers initiate circadian oscillator function by activating per and tim transcription, a Clk-GFP transgene was used to mark when late pacemaker neurons begin to develop. We were surprised to see that CLK-GFP was already expressed in four of five clusters of late pacemaker neurons during the third instar (L3) larval stage. CLK-GFP is only detected in postmitotic neurons from L3 larvae, suggesting that these four late pacemaker neuron clusters are formed before the L3 larval stage. A GFP-cyc transgene was used to show that CYC, like CLK, is also expressed exclusively in pacemaker neurons from L3 larval brains, demonstrating that CLK-CYC is not sufficient to activate per and tim in late pacemaker neurons at the L3 larval stage. These results suggest that most late pacemaker neurons develop days before novel factors activate circadian oscillator function during metamorphosis.