RESUMO
Defects in nucleocytoplasmic transport have been identified as a key pathogenic event in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) mediated by a GGGGCC hexanucleotide repeat expansion in C9ORF72, the most common genetic cause of ALS/FTD. Furthermore, nucleocytoplasmic transport disruption has also been implicated in other neurodegenerative diseases with protein aggregation, suggesting a shared mechanism by which protein stress disrupts nucleocytoplasmic transport. Here, we show that cellular stress disrupts nucleocytoplasmic transport by localizing critical nucleocytoplasmic transport factors into stress granules, RNA/protein complexes that play a crucial role in ALS pathogenesis. Importantly, inhibiting stress granule assembly, such as by knocking down Ataxin-2, suppresses nucleocytoplasmic transport defects as well as neurodegeneration in C9ORF72-mediated ALS/FTD. Our findings identify a link between stress granule assembly and nucleocytoplasmic transport, two fundamental cellular processes implicated in the pathogenesis of C9ORF72-mediated ALS/FTD and other neurodegenerative diseases.
Assuntos
Transporte Ativo do Núcleo Celular/fisiologia , Esclerose Lateral Amiotrófica/patologia , Ataxina-2/metabolismo , Proteína C9orf72/genética , Demência Frontotemporal/patologia , Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Idoso , Esclerose Lateral Amiotrófica/metabolismo , Arsenitos/toxicidade , Ataxina-2/antagonistas & inibidores , Ataxina-2/genética , Proteína C9orf72/metabolismo , Expansão das Repetições de DNA/genética , Feminino , Demência Frontotemporal/metabolismo , Células HEK293 , Humanos , Masculino , Glicoproteínas de Membrana/metabolismo , Pessoa de Meia-Idade , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Compostos de Sódio/toxicidade , alfa Carioferinas/antagonistas & inibidores , alfa Carioferinas/genética , alfa Carioferinas/metabolismo , beta Carioferinas/antagonistas & inibidores , beta Carioferinas/genética , beta Carioferinas/metabolismo , Proteína ran de Ligação ao GTP/antagonistas & inibidores , Proteína ran de Ligação ao GTP/genética , Proteína ran de Ligação ao GTP/metabolismoRESUMO
Reactive oxygen species (ROS) and mitochondrial defects in neurons are implicated in neurodegenerative disease. Here, we find that a key consequence of ROS and neuronal mitochondrial dysfunction is the accumulation of lipid droplets (LD) in glia. In Drosophila, ROS triggers c-Jun-N-terminal Kinase (JNK) and Sterol Regulatory Element Binding Protein (SREBP) activity in neurons leading to LD accumulation in glia prior to or at the onset of neurodegeneration. The accumulated lipids are peroxidated in the presence of ROS. Reducing LD accumulation in glia and lipid peroxidation via targeted lipase overexpression and/or lowering ROS significantly delays the onset of neurodegeneration. Furthermore, a similar pathway leads to glial LD accumulation in Ndufs4 mutant mice with neuronal mitochondrial defects, suggesting that LD accumulation following mitochondrial dysfunction is an evolutionarily conserved phenomenon, and represents an early, transient indicator and promoter of neurodegenerative disease.
Assuntos
Gotículas Lipídicas/metabolismo , Mitocôndrias/metabolismo , Neuroglia/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Animais , Complexo I de Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/metabolismo , MAP Quinase Quinase 4/metabolismo , Camundongos , Camundongos Knockout , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Neuroglia/patologia , Neurônios/patologia , Proteínas de Ligação a Elemento Regulador de Esterol/metabolismoRESUMO
Integrated microwave photonics (MWP) is an intriguing technology for the generation, transmission and manipulation of microwave signals in chip-scale optical systems1,2. In particular, ultrafast processing of analogue signals in the optical domain with high fidelity and low latency could enable a variety of applications such as MWP filters3-5, microwave signal processing6-9 and image recognition10,11. An ideal integrated MWP processing platform should have both an efficient and high-speed electro-optic modulation block to faithfully perform microwave-optic conversion at low power and also a low-loss functional photonic network to implement various signal-processing tasks. Moreover, large-scale, low-cost manufacturability is required to monolithically integrate the two building blocks on the same chip. Here we demonstrate such an integrated MWP processing engine based on a 4 inch wafer-scale thin-film lithium niobate platform. It can perform multipurpose tasks with processing bandwidths of up to 67 GHz at complementary metal-oxide-semiconductor (CMOS)-compatible voltages. We achieve ultrafast analogue computation, namely temporal integration and differentiation, at sampling rates of up to 256 giga samples per second, and deploy these functions to showcase three proof-of-concept applications: solving ordinary differential equations, generating ultra-wideband signals and detecting edges in images. We further leverage the image edge detector to realize a photonic-assisted image segmentation model that can effectively outline the boundaries of melanoma lesion in medical diagnostic images. Our ultrafast lithium niobate MWP engine could provide compact, low-latency and cost-effective solutions for future wireless communications, high-resolution radar and photonic artificial intelligence.
Assuntos
Micro-Ondas , Nióbio , Óptica e Fotônica , Óxidos , Fótons , Inteligência Artificial , Diagnóstico por Imagem/instrumentação , Diagnóstico por Imagem/métodos , Melanoma/diagnóstico por imagem , Melanoma/patologia , Óptica e Fotônica/instrumentação , Óptica e Fotônica/métodos , Radar , Tecnologia sem Fio , HumanosRESUMO
Invertebrate model systems are powerful tools for studying human disease owing to their genetic tractability and ease of screening. We conducted a mosaic genetic screen of lethal mutations on the Drosophila X chromosome to identify genes required for the development, function, and maintenance of the nervous system. We identified 165 genes, most of whose function has not been studied in vivo. In parallel, we investigated rare variant alleles in 1,929 human exomes from families with unsolved Mendelian disease. Genes that are essential in flies and have multiple human homologs were found to be likely to be associated with human diseases. Merging the human data sets with the fly genes allowed us to identify disease-associated mutations in six families and to provide insights into microcephaly associated with brain dysgenesis. This bidirectional synergism between fly genetics and human genomics facilitates the functional annotation of evolutionarily conserved genes involved in human health.
Assuntos
Doença/genética , Drosophila melanogaster/genética , Testes Genéticos , Padrões de Herança , Interferência de RNA , Animais , Modelos Animais de Doenças , Humanos , Cromossomo XRESUMO
In mammals, chromatin organization undergoes drastic reorganization during oocyte development. However, the dynamics of three-dimensional chromatin structure in this process is poorly characterized. Using low-input Hi-C (genome-wide chromatin conformation capture), we found that a unique chromatin organization gradually appears during mouse oocyte growth. Oocytes at late stages show self-interacting, cohesin-independent compartmental domains marked by H3K27me3, therefore termed Polycomb-associating domains (PADs). PADs and inter-PAD (iPAD) regions form compartment-like structures with strong inter-domain interactions among nearby PADs. PADs disassemble upon meiotic resumption from diplotene arrest but briefly reappear on the maternal genome after fertilization. Upon maternal depletion of Eed, PADs are largely intact in oocytes, but their reestablishment after fertilization is compromised. By contrast, depletion of Polycomb repressive complex 1 (PRC1) proteins attenuates PADs in oocytes, which is associated with substantial gene de-repression in PADs. These data reveal a critical role of Polycomb in regulating chromatin architecture during mammalian oocyte growth and early development.
Assuntos
Cromatina/química , Oócitos/crescimento & desenvolvimento , Oogênese/genética , Proteínas do Grupo Polycomb/fisiologia , Animais , Blastocisto/química , Proteínas de Ciclo Celular/fisiologia , Proteínas Cromossômicas não Histona/fisiologia , Embrião de Mamíferos/química , Inativação Gênica , Código das Histonas , Camundongos , Oócitos/química , Transcrição Gênica , CoesinasRESUMO
Somatic cell nuclear transfer (SCNT) can reprogram a somatic nucleus to a totipotent state. However, the re-organization of 3D chromatin structure in this process remains poorly understood. Using low-input Hi-C, we revealed that, during SCNT, the transferred nucleus first enters a mitotic-like state (premature chromatin condensation). Unlike fertilized embryos, SCNT embryos show stronger topologically associating domains (TADs) at the 1-cell stage. TADs become weaker at the 2-cell stage, followed by gradual consolidation. Compartments A/B are markedly weak in 1-cell SCNT embryos and become increasingly strengthened afterward. By the 8-cell stage, somatic chromatin architecture is largely reset to embryonic patterns. Unexpectedly, we found cohesin represses minor zygotic genome activation (ZGA) genes (2-cell-specific genes) in pluripotent and differentiated cells, and pre-depleting cohesin in donor cells facilitates minor ZGA and SCNT. These data reveal multi-step reprogramming of 3D chromatin architecture during SCNT and support dual roles of cohesin in TAD formation and minor ZGA repression.
Assuntos
Proteínas de Ciclo Celular/fisiologia , Cromatina/fisiologia , Proteínas Cromossômicas não Histona/fisiologia , Técnicas de Transferência Nuclear , Zigoto/fisiologia , Animais , Linhagem Celular , Núcleo Celular , Montagem e Desmontagem da Cromatina , Biologia Computacional/métodos , Conjuntos de Dados como Assunto , Desenvolvimento Embrionário , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , CoesinasRESUMO
Transcription elongation is increasingly recognized as an important mechanism of gene regulation. Here, we show that microprocessor controls gene expression in an RNAi-independent manner. Microprocessor orchestrates the recruitment of termination factors Setx and Xrn2, and the 3'-5' exoribonuclease, Rrp6, to initiate RNAPII pausing and premature termination at the HIV-1 promoter through cleavage of the stem-loop RNA, TAR. Rrp6 further processes the cleavage product, which generates a small RNA that is required to mediate potent transcriptional repression and chromatin remodeling at the HIV-1 promoter. Using chromatin immunoprecipitation coupled to high-throughput sequencing (ChIP-seq), we identified cellular gene targets whose transcription is modulated by microprocessor. Our study reveals RNAPII pausing and premature termination mediated by the co-operative activity of ribonucleases, Drosha/Dgcr8, Xrn2, and Rrp6, as a regulatory mechanism of RNAPII-dependent transcription elongation.
Assuntos
Exorribonucleases/metabolismo , Complexo Multienzimático de Ribonucleases do Exossomo/metabolismo , Regulação Viral da Expressão Gênica , HIV-1/genética , RNA Helicases/metabolismo , RNA Polimerase II/metabolismo , Transcrição Gênica , Sequência de Bases , Montagem e Desmontagem da Cromatina , Imunoprecipitação da Cromatina , DNA Helicases , Repetição Terminal Longa de HIV , Humanos , Dados de Sequência Molecular , Enzimas Multifuncionais , Regiões Promotoras Genéticas , Interferência de RNA , RNA Viral/química , RNA Viral/genética , Fatores de Transcrição/metabolismoRESUMO
Endoplasmic reticulum (ER)-associated degradation (ERAD) plays key roles in controlling protein levels and quality in eukaryotes. The Ring Finger Protein 185 (RNF185)/membralin ubiquitin ligase complex was recently identified as a branch in mammals and is essential for neuronal function, but its function in plant development is unknown. Here, we report the map-based cloning and characterization of Narrow Leaf and Dwarfism 1 (NLD1), which encodes the ER membrane-localized protein membralin and specifically interacts with maize homologs of RNF185 and related components. The nld1 mutant shows defective leaf and root development due to reduced cell number. The defects of nld1 were largely restored by expressing membralin genes from Arabidopsis thaliana and mice, highlighting the conserved roles of membralin proteins in animals and plants. The excessive accumulation of ß-hydroxy ß-methylglutaryl-CoA reductase in nld1 indicates that the enzyme is a membralin-mediated ERAD target. The activation of bZIP60 mRNA splicing-related unfolded protein response signaling and marker gene expression in nld1, as well as DNA fragment and cell viability assays, indicate that membralin deficiency induces ER stress and cell death in maize, thereby affecting organogenesis. Our findings uncover the conserved, indispensable role of the membralin-mediated branch of the ERAD pathway in plants. In addition, ZmNLD1 contributes to plant architecture in a dose-dependent manner, which can serve as a potential target for genetic engineering to shape ideal plant architecture, thereby enhancing high-density maize yields.
Assuntos
Degradação Associada com o Retículo Endoplasmático , Proteínas de Plantas , Ubiquitina-Proteína Ligases , Zea mays , Zea mays/genética , Zea mays/metabolismo , Zea mays/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genética , Retículo Endoplasmático/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Animais , Regulação da Expressão Gênica de Plantas , Estresse do Retículo Endoplasmático , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Camundongos , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Folhas de Planta/metabolismo , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Resposta a Proteínas não DobradasRESUMO
Understanding the transient dynamics of interlinked social-ecological systems (SES) is imperative for assessing sustainability in the Anthropocene. However, how to identify critical transitions in real-world SES remains a formidable challenge. In this study, we present an evolutionary framework to characterize these dynamics over an extended historical timeline. Our approach leverages multidecadal rates of change in socioeconomic data, paleoenvironmental, and cutting-edge sedimentary ancient DNA records from China's Yangtze River Delta, one of the most densely populated and intensively modified landscapes on Earth. Our analysis reveals two significant social-ecological transitions characterized by contrasting interactions and feedback spanning several centuries. Initially, the regional SES exhibited a loosely connected and ecologically sustainable regime. Nevertheless, starting in the 1950s, an increasingly interconnected regime emerged, ultimately resulting in the crossing of tipping points and an unprecedented acceleration in soil erosion, water eutrophication, and ecosystem degradation. Remarkably, the second transition occurring around the 2000s, featured a notable decoupling of socioeconomic development from ecoenvironmental degradation. This decoupling phenomenon signifies a more desirable reconfiguration of the regional SES, furnishing essential insights not only for the Yangtze River Basin but also for regions worldwide grappling with similar sustainability challenges. Our extensive multidecadal empirical investigation underscores the value of coevolutionary approaches in understanding and addressing social-ecological system dynamics.
Assuntos
Ecossistema , Rios , Eutrofização , Conservação dos Recursos Naturais/métodosRESUMO
Anxiety is a remarkably common condition among patients with pharyngitis, but the relationship between these disorders has received little research attention, and the underlying neural mechanisms remain unknown. Here, we show that the densely innervated pharynx transmits signals induced by pharyngeal inflammation to glossopharyngeal and vagal sensory neurons of the nodose/jugular/petrosal (NJP) superganglia in mice. Specifically, the NJP superganglia project to norepinephrinergic neurons in the nucleus of the solitary tract (NTSNE). These NTSNE neurons project to the ventral bed nucleus of the stria terminalis (vBNST) that induces anxiety-like behaviors in a murine model of pharyngeal inflammation. Inhibiting this pharynxâNJPâNTSNEâvBNST circuit can alleviate anxiety-like behaviors associated with pharyngeal inflammation. This study thus defines a pharynx-to-brain axis that mechanistically links pharyngeal inflammation and emotional response.
Assuntos
Faringite , Faringe , Humanos , Animais , Camundongos , Ansiedade , Encéfalo , Células Receptoras Sensoriais , InflamaçãoRESUMO
The nonstructural protein 1 (Nsp1) of SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) is a virulence factor that targets multiple cellular pathways to inhibit host gene expression and antiviral response. However, the underlying mechanisms of the various Nsp1-mediated functions and their contributions to SARS-CoV-2 virulence remain unclear. Among the targets of Nsp1 is the mRNA (messenger ribonucleic acid) export receptor NXF1-NXT1, which mediates nuclear export of mRNAs from the nucleus to the cytoplasm. Based on Nsp1 crystal structure, we generated mutants on Nsp1 surfaces and identified an acidic N-terminal patch that is critical for interaction with NXF1-NXT1. Photoactivatable Nsp1 probe reveals the RNA Recognition Motif (RRM) domain of NXF1 as an Nsp1 N-terminal binding site. By mutating the Nsp1 N-terminal acidic patch, we identified a separation-of-function mutant of Nsp1 that retains its translation inhibitory function but substantially loses its interaction with NXF1 and reverts Nsp1-mediated mRNA export inhibition. We then generated a recombinant (r)SARS-CoV-2 mutant on the Nsp1 N-terminal acidic patch and found that this surface is key to promote NXF1 binding and inhibition of host mRNA nuclear export, viral replication, and pathogenicity in vivo. Thus, these findings provide a mechanistic understanding of Nsp1-mediated mRNA export inhibition and establish the importance of this pathway in the virulence of SARS-CoV-2.
Assuntos
Transporte Ativo do Núcleo Celular , COVID-19 , Proteínas de Transporte Nucleocitoplasmático , RNA Mensageiro , Proteínas de Ligação a RNA , SARS-CoV-2 , Proteínas não Estruturais Virais , Humanos , SARS-CoV-2/metabolismo , SARS-CoV-2/patogenicidade , SARS-CoV-2/genética , Proteínas não Estruturais Virais/metabolismo , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/química , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Transporte Nucleocitoplasmático/metabolismo , Proteínas de Transporte Nucleocitoplasmático/genética , Animais , COVID-19/virologia , COVID-19/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Replicação Viral , Núcleo Celular/metabolismo , Células Vero , Virulência , Chlorocebus aethiops , Células HEK293RESUMO
A large number of studies have established a causal relationship between the gut microbiota and human disease. In addition, the composition of the microbiota is substantially influenced by the human genome. Modern medical research has confirmed that the pathogenesis of various diseases is closely related to evolutionary events in the human genome. Specific regions of the human genome known as human accelerated regions (HARs) have evolved rapidly over several million years since humans diverged from a common ancestor with chimpanzees, and HARs have been found to be involved in some human-specific diseases. Furthermore, the HAR-regulated gut microbiota has undergone rapid changes during human evolution. We propose that the gut microbiota may serve as an important mediator linking diseases to human genome evolution.
Assuntos
Microbioma Gastrointestinal , Hominidae , Microbiota , Animais , Humanos , Microbioma Gastrointestinal/genética , Genoma Humano/genética , Hominidae/genética , Pan troglodytes/genética , Evolução MolecularRESUMO
BACKGROUND: Increasing evidence suggests that long noncoding RNAs play significant roles in vascular biology and disease development. One such long noncoding RNA, PSMB8-AS1, has been implicated in the development of tumors. Nevertheless, the precise role of PSMB8-AS1 in cardiovascular diseases, particularly atherosclerosis, has not been thoroughly elucidated. Thus, the primary aim of this investigation is to assess the influence of PSMB8-AS1 on vascular inflammation and the initiation of atherosclerosis. METHODS: We generated PSMB8-AS1 knockin and Apoe (Apolipoprotein E) knockout mice (Apoe-/-PSMB8-AS1KI) and global Apoe and proteasome subunit-ß type-9 (Psmb9) double knockout mice (Apoe-/-Psmb9-/-). To explore the roles of PSMB8-AS1 and Psmb9 in atherosclerosis, we fed the mice with a Western diet for 12 weeks. RESULTS: Long noncoding RNA PSMB8-AS1 is significantly elevated in human atherosclerotic plaques. Strikingly, Apoe-/-PSMB8-AS1KI mice exhibited increased atherosclerosis development, plaque vulnerability, and vascular inflammation compared with Apoe-/- mice. Moreover, the levels of VCAM1 (vascular adhesion molecule 1) and ICAM1 (intracellular adhesion molecule 1) were significantly upregulated in atherosclerotic lesions and serum of Apoe-/-PSMB8-AS1KI mice. Consistently, in vitro gain- and loss-of-function studies demonstrated that PSMB8-AS1 induced monocyte/macrophage adhesion to endothelial cells and increased VCAM1 and ICAM1 levels in a PSMB9-dependent manner. Mechanistic studies revealed that PSMB8-AS1 induced PSMB9 transcription by recruiting the transcription factor NONO (non-POU domain-containing octamer-binding protein) and binding to the PSMB9 promoter. PSMB9 (proteasome subunit-ß type-9) elevated VCAM1 and ICAM1 expression via the upregulation of ZEB1 (zinc finger E-box-binding homeobox 1). Psmb9 deficiency decreased atherosclerotic lesion size, plaque vulnerability, and vascular inflammation in Apoe-/- mice in vivo. Importantly, endothelial overexpression of PSMB8-AS1-increased atherosclerosis and vascular inflammation were attenuated by Psmb9 knockout. CONCLUSIONS: PSMB8-AS1 promotes vascular inflammation and atherosclerosis via the NONO/PSMB9/ZEB1 axis. Our findings support the development of new long noncoding RNA-based strategies to counteract atherosclerotic cardiovascular disease.
Assuntos
Aterosclerose , Placa Aterosclerótica , RNA Longo não Codificante , Animais , Humanos , Camundongos , Apolipoproteínas E/genética , Aterosclerose/metabolismo , Células Endoteliais/metabolismo , Inflamação/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Placa Aterosclerótica/patologia , Complexo de Endopeptidases do Proteassoma/genética , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismoRESUMO
circRNADisease v2.0 is an enhanced and reliable database that offers experimentally verified relationships between circular RNAs (circRNAs) and various diseases. It is accessible at http://cgga.org.cn/circRNADisease/ or http://cgga.org.cn:9091/circRNADisease/. The database currently includes 6998 circRNA-disease entries across multiple species, representing a remarkable 19.77-fold increase compared to the previous version. This expansion consists of a substantial rise in the number of circRNAs (from 330 to 4246), types of diseases (from 48 to 330) and covered species (from human only to 12 species). Furthermore, a new section has been introduced in the database, which collects information on circRNA-associated factors (genes, proteins and microRNAs), molecular mechanisms (molecular pathways), biological functions (proliferation, migration, invasion, etc.), tumor and/or cell line and/or patient-derived xenograft (PDX) details, and prognostic evidence in diseases. In addition, we identified 7 159 865 relationships between mutations and circRNAs among 30 TCGA cancer types. Due to notable enhancements and extensive data expansions, the circRNADisease 2.0 database has become an invaluable asset for both clinical practice and fundamental research. It enables researchers to develop a more comprehensive understanding of how circRNAs impact complex diseases.
Assuntos
Bases de Dados Genéticas , Neoplasias , RNA Circular , Humanos , Linhagem Celular , Neoplasias/genéticaRESUMO
Although homologous recombination between transposable elements can drive genomic evolution in yeast by facilitating chromosomal rearrangements, the details of the underlying mechanisms are not fully clarified. In the genome of the yeast Saccharomyces cerevisiae, the most common class of transposon is the retrotransposon Ty1. Here, we explored how Cas9-induced double-strand breaks (DSBs) directed to Ty1 elements produce genomic alterations in this yeast species. Following Cas9 induction, we observed a significant elevation of chromosome rearrangements such as deletions, duplications and translocations. In addition, we found elevated rates of mitotic recombination, resulting in loss of heterozygosity. Using Southern analysis coupled with short- and long-read DNA sequencing, we revealed important features of recombination induced in retrotransposons. Almost all of the chromosomal rearrangements reflect the repair of DSBs at Ty1 elements by non-allelic homologous recombination; clustered Ty elements were hotspots for chromosome rearrangements. In contrast, a large proportion (about three-fourths) of the allelic mitotic recombination events have breakpoints in unique sequences. Our analysis suggests that some of the latter events reflect extensive processing of the broken ends produced in the Ty element that extend into unique sequences resulting in break-induced replication. Finally, we found that haploid and diploid strain have different preferences for the pathways used to repair double-stranded DNA breaks. Our findings demonstrate the importance of DNA lesions in retrotransposons in driving genome evolution.
Assuntos
Sistemas CRISPR-Cas , Saccharomyces cerevisiae , Humanos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Sistemas CRISPR-Cas/genética , Quebras de DNA de Cadeia Dupla , Retroelementos/genética , Aberrações Cromossômicas , Recombinação Homóloga/genéticaRESUMO
An optical blackbody is an ideal absorber for all incident optical radiation, and the theoretical study of its radiation spectra paved the way for quantum mechanics (Planck's law). Herein, we propose the concept of an electron blackbody, which is a perfect electron absorber as well as an electron emitter with standard energy spectra at different temperatures. Vertically aligned carbon nanotube arrays are electron blackbodies with an electron absorption coefficient of 0.95 for incident energy ranging from 1 keV to 20 keV and standard electron emission spectra that fit well with the free electron gas model. Such a concept might also be generalized to blackbodies for extreme ultraviolet, X-ray, and γ-ray photons as well as neutrons, protons, and other elementary particles.
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Capsid assembly is critical in the hepatitis B virus (HBV) life cycle, mediated by the viral core protein. Capsid assembly is the target for new anti-viral therapeutics known as capsid assembly modulators (CAMs) of which the CAM-aberrant (CAM-A) class induces aberrant shaped core protein structures and leads to hepatocyte cell death. This study aimed to identify the mechanism of action of CAM-A modulators leading to HBV-infected hepatocyte elimination where CAM-A-mediated hepatitis B surface antigen (HBsAg) reduction was evaluated in a stable HBV replicating cell line and in AAV-HBV-transduced C57BL/6, C57BL/6 SCID, and HBV-infected chimeric mice with humanized livers. Results showed that in vivo treatment with CAM-A modulators induced pronounced reductions in hepatitis B e antigen (HBeAg) and HBsAg, associated with a transient alanine amino transferase (ALT) increase. Both HBsAg and HBeAg reductions and ALT increase were delayed in C57BL/6 SCID and chimeric mice, suggesting that adaptive immune responses may indirectly contribute. However, CD8+ T cell depletion in transduced wild-type mice did not impact antigen reduction, indicating that CD8+ T cell responses are not essential. Transient ALT elevation in AAV-HBV-transduced mice coincided with a transient increase in endoplasmic reticulum stress and apoptosis markers, followed by detection of a proliferation marker. Microarray data revealed antigen presentation pathway (major histocompatibility complex class I molecules) upregulation, overlapping with the apoptosis. Combination treatment with HBV-specific siRNA demonstrated that CAM-A-mediated HBsAg reduction is dependent on de novo core protein translation. To conclude, CAM-A treatment eradicates HBV-infected hepatocytes with high core protein levels through the induction of apoptosis, which can be a promising approach as part of a regimen to achieve functional cure. IMPORTANCE: Treatment with hepatitis B virus (HBV) capsid assembly modulators that induce the formation of aberrant HBV core protein structures (CAM-A) leads to programmed cell death, apoptosis, of HBV-infected hepatocytes and subsequent reduction of HBV antigens, which differentiates CAM-A from other CAMs. The effect is dependent on the de novo synthesis and high levels of core protein.
Assuntos
Antivirais , Apoptose , Regulação Viral da Expressão Gênica , Antígenos do Núcleo do Vírus da Hepatite B , Vírus da Hepatite B , Hepatócitos , Biossíntese de Proteínas , Animais , Camundongos , Antivirais/farmacologia , Antivirais/uso terapêutico , Apoptose/efeitos dos fármacos , Capsídeo/química , Capsídeo/classificação , Capsídeo/efeitos dos fármacos , Capsídeo/metabolismo , Proteínas do Capsídeo/metabolismo , Hepatite B/tratamento farmacológico , Hepatite B/imunologia , Hepatite B/metabolismo , Hepatite B/virologia , Antígenos do Núcleo do Vírus da Hepatite B/biossíntese , Antígenos do Núcleo do Vírus da Hepatite B/metabolismo , Antígenos E da Hepatite B/metabolismo , Antígenos de Superfície da Hepatite B/metabolismo , Vírus da Hepatite B/crescimento & desenvolvimento , Vírus da Hepatite B/imunologia , Vírus da Hepatite B/metabolismo , Vírus da Hepatite B/patogenicidade , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Hepatócitos/patologia , Hepatócitos/virologia , Camundongos Endogâmicos C57BL , Camundongos SCID , Replicação Viral , Linhagem Celular , Linfócitos T CD8-Positivos/imunologia , Apresentação de AntígenoRESUMO
Ammonia (NH3) is a key commodity chemical for the agricultural, textile and pharmaceutical industries, but its production via the Haber-Bosch process is carbon-intensive and centralized. Alternatively, an electrochemical method could enable decentralized, ambient NH3 production that can be paired with renewable energy. The first verified electrochemical method for NH3 synthesis was a process mediated by lithium (Li) in organic electrolytes. So far, however, elements other than Li remain unexplored in this process for potential benefits in efficiency, reaction rates, device design, abundance and stability. In our demonstration of a Li-free system, we found that calcium can mediate the reduction of nitrogen for NH3 synthesis. We verified the calcium-mediated process using a rigorous protocol and achieved an NH3 Faradaic efficiency of 40 ± 2% using calcium tetrakis(hexafluoroisopropyloxy)borate (Ca[B(hfip)4]2) as the electrolyte. Our results offer the possibility of using abundant materials for the electrochemical production of NH3, a critical chemical precursor and promising energy vector.
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Rosmarinic acid (RA) is an important medicinal metabolite and a potent food antioxidant. We discovered that exposure to high light intensifies the accumulation of RA in the leaves of perilla (Perilla frutescens (L.) Britt). However, the molecular mechanism underlying RA synthesis in response to high light stress remains poorly understood. To address this knowledge gap, we conducted a comprehensive analysis employing transcriptomic sequencing, transcriptional activation, and genetic transformation techniques. High light treatment for 1 and 48â h resulted in the upregulation of 592 and 1,060 genes, respectively. Among these genes, three structural genes and 93 transcription factors exhibited co-expression. Notably, NAC family member PfNAC2, GBF family member PfGBF3, and cinnamate-4-hydroxylase gene PfC4H demonstrated significant co-expression and upregulation under high light stress. Transcriptional activation analysis revealed that PfGBF3 binds to and activates the PfNAC2 promoter. Additionally, both PfNAC2 and PfGBF3 bind to the PfC4H promoter, thereby positively regulating PfC4H expression. Transient overexpression of PfNAC2, PfGBF3, and PfC4H, as well as stable transgenic expression of PfNAC2, led to a substantial increase in RA accumulation in perilla. Consequently, PfGBF3 acts as a photosensitive factor that positively regulates PfNAC2 and PfC4H, while PfNAC2 also regulates PfC4H to promote RA accumulation under high light stress. The elucidation of the regulatory mechanism governing RA accumulation in perilla under high light conditions provides a foundation for developing a high-yield RA system and a model to understand light-induced metabolic accumulation.
Assuntos
Cinamatos , Depsídeos , Regulação da Expressão Gênica de Plantas , Luz , Proteínas de Plantas , Ácido Rosmarínico , Depsídeos/metabolismo , Cinamatos/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Perilla frutescens/genética , Perilla frutescens/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/genética , Folhas de Planta/efeitos da radiação , Regiões Promotoras Genéticas/genéticaRESUMO
Natural Nicotinamide Adenine Dinucleotide (NAD+) precursors have attracted much attention due to their positive effects in promoting ovarian health. However, their target tissue, synthesis efficiency, advantages, and disadvantages are still unclear. This review summarizes the distribution of NAD+ at the tissue, cellular and subcellular levels, discusses its biosynthetic pathways and the latest findings in ovary, include: (1) NAD+ plays distinct roles both intracellularly and extracellularly, adapting its distribution in response to requirements. (2) Different precursors differs in target tissues, synthetic efficiency, biological utilization, and adverse effects. Importantly: tryptophan is primarily utilized in the liver and kidneys, posing metabolic risks in excess; nicotinamide (NAM) is indispensable for maintaining NAD+ levels; nicotinic acid (NA) constructs a crucial bridge between intestinal microbiota and the host with diverse functions; nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) increase NAD+ systemically and can be influenced by delivery route, tissue specificity, and transport efficiency. (3) The biosynthetic pathways of NAD+ are intricately intertwined. They provide multiple sources and techniques for NAD+ synthesis, thereby reducing the dependence on a single molecule to maintain cellular NAD+ levels. However, an excess of a specific precursor potentially influencing other pathways. In addition, Protein expression analysis suggest that ovarian tissues may preferentially utilize NAM and NMN. These findings summarize the specific roles and potential of NAD+ precursors in enhancing ovarian health. Future research should delve into the molecular mechanisms and intervention strategies of different precursors, aiming to achieve personalized prevention or treatment of ovarian diseases, and reveal their clinical application value.