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Expansion of CAG trinucleotide repeats in ATXN1 causes spinocerebellar ataxia type 1 (SCA1), a neurodegenerative disease that impairs coordination and cognition. While ATXN1 is associated with increased Alzheimer's disease (AD) risk, CAG repeat number in AD patients is not changed. Here, we investigated the consequences of ataxin-1 loss of function and discovered that knockout of Atxn1 reduced CIC-ETV4/5-mediated inhibition of Bace1 transcription, leading to increased BACE1 levels and enhanced amyloidogenic cleavage of APP, selectively in AD-vulnerable brain regions. Elevated BACE1 expression exacerbated Aß deposition and gliosis in AD mouse models and impaired hippocampal neurogenesis and olfactory axonal targeting. In SCA1 mice, polyglutamine-expanded mutant ataxin-1 led to the increase of BACE1 post-transcriptionally, both in cerebrum and cerebellum, and caused axonal-targeting deficit and neurodegeneration in the hippocampal CA2 region. These findings suggest that loss of ataxin-1 elevates BACE1 expression and Aß pathology, rendering it a potential contributor to AD risk and pathogenesis.
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Doença de Alzheimer/patologia , Secretases da Proteína Precursora do Amiloide/metabolismo , Ataxina-1/metabolismo , Encéfalo/metabolismo , Doença de Alzheimer/metabolismo , Secretases da Proteína Precursora do Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Ataxina-1/deficiência , Ataxina-1/genética , Encéfalo/patologia , Região CA2 Hipocampal/metabolismo , Região CA2 Hipocampal/patologia , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Modelos Animais de Doenças , Feminino , Frequência do Gene , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Neurogênese , Proteínas Proto-Oncogênicas c-ets/genética , Proteínas Proto-Oncogênicas c-ets/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcrição Gênica , Repetições de Trinucleotídeos/genética , Regulação para CimaRESUMO
ß- and γ-herpesviruses transcribe their late genes in a manner distinct from host transcription. This process is directed by a complex of viral transcriptional activator proteins that hijack cellular RNA polymerase II and an unknown set of additional factors. We employed proximity labeling coupled with mass spectrometry, followed by CRISPR and siRNA screening to identify proteins functionally associated with the Kaposi's sarcoma-associated herpesvirus (KSHV) late gene transcriptional complex. These data revealed that the catalytic subunit of the viral DNA packaging motor, ORF29, is both dynamically associated with the viral transcriptional activator complex and potentiates gene expression late in infection. Through genetic mutation and deletion of ORF29, we establish that its catalytic activity potentiates viral transcription and is required for robust accumulation of essential late proteins during infection. Thus, we propose an expanded role for ORF29 that encompasses its established function in viral packaging and its newly discovered contributions to viral transcription and late gene expression in KSHV.
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Herpesvirus Humano 8 , Herpesvirus Humano 8/genética , Herpesvirus Humano 8/metabolismo , Empacotamento do Genoma Viral , Replicação Viral , Proteínas Virais/genética , Proteínas Virais/metabolismo , Expressão Gênica , Regulação Viral da Expressão GênicaRESUMO
Alkaline exonucleases (AE) are present in several large DNA viruses including bacteriophage λ and herpesviruses, where they play roles in viral DNA processing during genome replication. Given the genetic conservation of AEs across viruses infecting different kingdoms of life, these enzymes likely assume central roles in the lifecycles of viruses where they have yet to be well characterized. Here, we applied a structure-guided functional analysis of the bifunctional AE in the oncogenic human gammaherpesvirus Kaposi's sarcoma-associated herpesvirus (KSHV), called SOX. In addition to identifying a preferred DNA substrate preference for SOX, we define key residues important for DNA binding and DNA processing, and how SOX activity on DNA partially overlaps with its functionally separable cleavage of mRNA. By engineering these SOX mutants into KSHV, we reveal roles for its DNase activity in viral gene expression and infectious virion production. Our results provide mechanistic insight into gammaherpesviral AE activity as well as areas of functional conservation between this mammalian virus AE and its distant relative in phage λ.
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Exonucleases , Herpesvirus Humano 8 , Animais , Humanos , DNA Viral/metabolismo , Exonucleases/genética , Expressão Gênica , Regulação Viral da Expressão Gênica , Herpesvirus Humano 8/metabolismo , Mamíferos/genética , Vírion/metabolismo , Replicação ViralRESUMO
While traditional methods for studying large DNA viruses allow the creation of individual mutants, CRISPR/Cas9 can be used to rapidly create thousands of mutant dsDNA viruses in parallel, enabling the pooled screening of entire viral genomes. Here, we applied this approach to Kaposi's sarcoma-associated herpesvirus (KSHV) by designing a sgRNA library containing all possible ~22,000 guides targeting the 154 kilobase viral genome, corresponding to one cut site approximately every 8 base pairs. We used the library to profile viral sequences involved in transcriptional activation of late genes, whose regulation involves several well characterized features including dependence on viral DNA replication and a known set of viral transcriptional activators. Upon phenotyping all possible Cas9-targeted viruses for transcription of KSHV late genes we recovered these established regulators and identified a new required factor (ORF46), highlighting the utility of the screening pipeline. By performing targeted deep sequencing of the viral genome to distinguish between knock-out and in-frame alleles created by Cas9, we identify the DNA binding but not catalytic domain of ORF46 to be required for viral DNA replication and thus late gene expression. Our pooled Cas9 tiling screen followed by targeted deep viral sequencing represents a two-tiered screening paradigm that may be widely applicable to dsDNA viruses.
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Regulação Viral da Expressão Gênica/fisiologia , Genes Virais/genética , Herpesvirus Humano 8/genética , Sistemas CRISPR-Cas , Células HEK293 , HumanosRESUMO
The mRNA 5' cap structure serves both to protect transcripts from degradation and promote their translation. Cap removal is thus an integral component of mRNA turnover that is carried out by cellular decapping enzymes, whose activity is tightly regulated and coupled to other stages of the mRNA decay pathway. The poxvirus vaccinia virus (VACV) encodes its own decapping enzymes, D9 and D10, that act on cellular and viral mRNA, but may be regulated differently than their cellular counterparts. Here, we evaluated the targeting potential of these viral enzymes using RNA sequencing from cells infected with wild-type and decapping mutant versions of VACV as well as in uninfected cells expressing D10. We found that D9 and D10 target an overlapping subset of viral transcripts but that D10 plays a dominant role in depleting the vast majority of human transcripts, although not in an indiscriminate manner. Unexpectedly, the splicing architecture of a gene influences how robustly its corresponding transcript is targeted by D10, as transcripts derived from intronless genes are less susceptible to enzymatic decapping by D10. As all VACV genes are intronless, preferential decapping of transcripts from intron-containing genes provides an unanticipated mechanism for the virus to disproportionately deplete host transcripts and remodel the infected cell transcriptome.
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Poxviridae , Vaccinia virus , Endorribonucleases/metabolismo , Humanos , Poxviridae/genética , Capuzes de RNA/genética , Capuzes de RNA/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Vaccinia virus/genética , Vaccinia virus/metabolismo , Proteínas Virais/metabolismoRESUMO
BACKGROUND: The use of technology in diabetes mellitus (DM) management has been growing. The indications and coverage for continuous glucose monitoring (CGM) have increased. Primary care (PC) clinics, including resident continuity clinics, are the frontline for DM management; however, they struggle to adopt CGM. AIM: To implement a CGM curriculum to resident physicians to improve knowledge and confidence. SETTING: An internal medicine (IM) resident PC clinic in an urban academic medical institution. PARTICIPANTS: Twenty-four IM residents. DESCRIPTION: We designed a curriculum that included a lecture about CGM indications, interpretation, ordering, and insurance consideration; and a voluntary, experiential learning module in which the residents wore a CGM. EVALUATION: We conducted a retrospective pre-post survey with a 4-point Likert scale. Average self-reported scores in knowledge increased for CGM (1) indications from 1.85 to 3.45, (2) ordering from 1.35 to 3.05, (3) functioning from 2.20 to 3.50, and (4) data interpretation from 1.85 to 3.25 (all p < 0.0001). Confidence for "describing CGM monitoring" and "fielding questions about CGM" increased from 2.25 to 3.65 (p < 0.0001) and 1.90 to 3.30 (p < 0.0001). DISCUSSION: Given the demand for DM management in the PC setting, this targeted CGM curriculum has promise to help residents adopt CGM into their practice.
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INTRODUCTION AND HYPOTHESIS: Pessary treatment for pelvic organ prolapse (POP) is effective and safe, but long-term continuation is low. Pain and vaginal discharge may play a role. This study was aimed at evaluating vaginal discharge and pain during pessary cleaning in an outpatient setting and in continuous pessary use. METHODS: Women with POP who attended the outpatient clinic for pessary cleaning between January and October 2021 were included. Primary outcome was pain during removal and reinsertion of the pessary, measured by an 11-point numeric rating scale (NRS). Secondary outcome was vaginal discharge, measured by the NRS and Patient Global Impression of Change scale (PGI-C). Multiple linear regression analysis was used to identify associated variables for pain and discharge. RESULTS: A total of 150 women were included. Mean NRS during pessary removal was 4.3 (± 2.7), with 25% of women scoring a 7 or higher. Mean NRS during reinsertion was 1.8 (± 2.0). A smaller genital hiatus and presence of vaginal atrophy or vulvar skin disease were associated with pain during pessary removal. Mean NRS for vaginal discharge was 2.5 (± 2.3). Twenty-five percent of women reported that their vaginal discharge was "(very) much worse" than before they used a pessary. Presence of vaginal erosions was associated with vaginal discharge in this study population. CONCLUSIONS: Removing a pessary in an outpatient setting is a painful procedure for many women who use a pessary continuously. Moreover, 25% of these women experience an increase in vaginal discharge while using a pessary. Future research should focus on reducing these disadvantages.
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Prolapso de Órgão Pélvico , Descarga Vaginal , Humanos , Feminino , Pessários/efeitos adversos , Pacientes Ambulatoriais , Descarga Vaginal/etiologia , Prolapso de Órgão Pélvico/terapia , Dor/etiologiaRESUMO
BACKGROUND: Although behavioral interventions show some promise for reducing stimulant use and achieving durable viral suppression in sexual minority men (SMM) with HIV, scalable mHealth applications are needed to optimize their reach and cost-effectiveness. METHODS: Supporting Treatment Adherence for Resilience and Thriving (START) is a randomized controlled trial (RCT) testing the efficacy and cost-effectiveness of a mHealth application that integrates evidence-based positive affect regulation skills with self-monitoring of adherence and mood. The primary outcome is detectable HIV viral load (i.e., > 300 copies/mL) from self-collected dried blood spot (DBS) specimens at 6 months. Secondary outcomes include detectable DBS viral load at 12 months, self-reported stimulant use severity, anti-retroviral therapy (ART) adherence, and positive affect over 12 months. A national sample of up to 250 SMM with HIV who screen positive for stimulant use disorder and reporting suboptimal ART adherence is being recruited via social networking applications through April of 2024. After providing informed consent, participants complete a run-in period (i.e., waiting period) including two baseline assessments with self-report measures and a self-collected DBS sample. Those who complete the run-in period are randomized to either the START mHealth application or access to a website with referrals to HIV care and substance use disorder treatment resources. Participants provide DBS samples at baseline, 6, and 12 months to measure HIV viral load as well as complete self-report measures for secondary outcomes at quarterly follow-up assessments over 12 months. DISCUSSION: To date, we have paid $117,500 to advertise START on social networking applications and reached 1,970 eligible participants ($59.77 per eligible participant). Although we identified this large national sample of potentially eligible SMM with HIV who screen positive for a stimulant use disorder and report suboptimal ART adherence, only one-in-four have enrolled in the RCT. The run-in period has proven to be crucial for maintaining scientific rigor and reproducibility of this RCT, such that only half of consented participants complete the required study enrollment activities and attended a randomization visit. Taken together, findings will guide adequate resource allocation to achieve randomization targets in future mHealth research SMM with HIV who use stimulants. TRIAL REGISTRATION: This protocol was registered on clinicaltrials.gov (NCT05140876) on December 2, 2021.
Assuntos
Infecções por HIV , Telemedicina , Adulto , Humanos , Masculino , Antirretrovirais/uso terapêutico , Análise Custo-Benefício , Infecções por HIV/tratamento farmacológico , Adesão à Medicação , Resiliência Psicológica , Minorias Sexuais e de Gênero/psicologia , Transtornos Relacionados ao Uso de Substâncias/terapia , Cooperação e Adesão ao Tratamento/psicologia , Carga Viral , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
Mapping host-pathogen interactions has proven instrumental for understanding how viruses manipulate host machinery and how numerous cellular processes are regulated. DNA viruses such as herpesviruses have relatively large coding capacity and thus can target an extensive network of cellular proteins. To identify the host proteins hijacked by this pathogen, we systematically affinity tagged and purified all 89 proteins of Kaposi's sarcoma-associated herpesvirus (KSHV) from human cells. Mass spectrometry of this material identified over 500 virus-host interactions. KSHV causes AIDS-associated cancers, and its interaction network is enriched for proteins linked to cancer and overlaps with proteins that are also targeted by HIV-1. We found that the conserved KSHV protein ORF24 binds to RNA polymerase II and brings it to viral late promoters by mimicking and replacing cellular TATA-box-binding protein (TBP). This is required for herpesviral late gene expression, a complex and poorly understood phase of the viral lifecycle.
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Herpesvirus Humano 8/fisiologia , Transcrição Gênica , Regulação Viral da Expressão Gênica , Células HEK293 , Interações Hospedeiro-Patógeno , Humanos , Mapeamento de Interação de Proteínas , Mapas de Interação de Proteínas , RNA Polimerase II/metabolismo , Proteína de Ligação a TATA-Box/metabolismo , Proteínas Virais/genética , Proteínas Virais/metabolismoRESUMO
OBJECTIVE: The aim was to compare the (sentinel) lymph node detection rate of indocyanine green (ICG)-fluorescent imaging versus standard-of-care 99m Tc-nanocoilloid for sentinel lymph node (SLN)-mapping. BACKGROUND: The current gold standard for axillary staging in patients with breast cancer is sentinel lymph node biopsy (SLNB) using radio-guided surgery using radioisotope technetium ( 99m Tc), sometimes combined with blue dye. A promising alternative is fluorescent imaging using ICG. METHODS: In this noninferiority trial, we enrolled 102 consecutive patients with invasive early-stage, clinically node-negative breast cancer. Patients were planned for breast conserving surgery and SLNB between August 2020 and June 2021. The day or morning before surgery, patients were injected with 99m Tc-nanocolloid. In each patient, SLNB was first performed using ICG-fluorescent imaging, after which excised lymph nodes were tested with the gamma-probe for 99m Tc-uptake ex vivo, and the axilla was checked for residual 99m Tc-activity. The detection rate was defined as the proportion of patients in whom at least 1 (S)LN was detected with either tracer. RESULTS: In total, 103 SLNBs were analyzed. The detection rate of ICG-fluorescence was 96.1% [95% confidence interval (95% CI)=90.4%-98.9%] versus 86.4% (95% CI=78.3%-92.4%) for 99m Tc-nanocoilloid. The detection rate for pathological lymph nodes was 86.7% (95% CI=59.5%-98.3%) for both ICG and 99m Tc-nanocoilloid. A median of 2 lymph nodes were removed. ICG-fluorescent imaging did not increase detection time. No adverse events were observed. CONCLUSIONS: ICG-fluorescence showed a higher (S)LN detection rate than 99m Tc-nanocoilloid, and equal detection rate for pathological (S)LNs. ICG-fluorescence may be used as a safe and effective alternative to 99m Tc-nanocoilloid for SLNB in patients with early-stage breast cancer.
Assuntos
Neoplasias da Mama , Linfonodo Sentinela , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Corantes , Feminino , Humanos , Verde de Indocianina , Linfonodos/diagnóstico por imagem , Linfonodos/patologia , Linfocintigrafia/métodos , Compostos Radiofarmacêuticos , Linfonodo Sentinela/diagnóstico por imagem , Linfonodo Sentinela/patologia , Linfonodo Sentinela/cirurgia , Biópsia de Linfonodo Sentinela/métodos , Tecnécio , Agregado de Albumina Marcado com Tecnécio Tc 99mRESUMO
In mammalian cells, widespread acceleration of cytoplasmic mRNA degradation is linked to impaired RNA polymerase II (Pol II) transcription. This mRNA decay-induced transcriptional repression occurs during infection with gammaherpesviruses including Kaposi's sarcoma-associated herpesvirus (KSHV) and murine gammaherpesvirus 68 (MHV68), which encode an mRNA endonuclease that initiates widespread RNA decay. Here, we show that MHV68-induced mRNA decay leads to a genome-wide reduction of Pol II occupancy at mammalian promoters. This reduced Pol II occupancy is accompanied by down-regulation of multiple Pol II subunits and TFIIB in the nucleus of infected cells, as revealed by mass spectrometry-based global measurements of protein abundance. Viral genes, despite the fact that they require Pol II for transcription, escape transcriptional repression. Protection is not governed by viral promoter sequences; instead, location on the viral genome is both necessary and sufficient to escape the transcriptional repression effects of mRNA decay. We propose a model in which the ability to escape from transcriptional repression is linked to the localization of viral DNA within replication compartments, providing a means for these viruses to counteract decay-induced transcript loss.
Assuntos
Infecções por Herpesviridae/metabolismo , Herpesvirus Humano 8/fisiologia , Regiões Promotoras Genéticas , RNA Polimerase II/metabolismo , Estabilidade de RNA , Rhadinovirus/fisiologia , Replicação Viral , Animais , Endonucleases/genética , Endonucleases/metabolismo , Genoma Viral , Infecções por Herpesviridae/genética , Camundongos , Células NIH 3T3 , RNA Polimerase II/genética , Fator de Transcrição TFIIB/genética , Fator de Transcrição TFIIB/metabolismo , Proteínas Virais/genética , Proteínas Virais/metabolismoRESUMO
ß- and γ-herpesviruses include the oncogenic human viruses Kaposi's sarcoma-associated virus (KSHV) and Epstein-Barr virus (EBV), and human cytomegalovirus (HCMV), which is a significant cause of congenital disease. Near the end of their replication cycle, these viruses transcribe their late genes in a manner distinct from host transcription. Late gene transcription requires six virally encoded proteins, one of which is a functional mimic of host TATA-box-binding protein (TBP) that is also involved in recruitment of RNA polymerase II (Pol II) via unknown mechanisms. Here, we applied biochemical protein interaction studies together with electron microscopy-based imaging of a reconstituted human preinitiation complex to define the mechanism underlying Pol II recruitment. These data revealed that the herpesviral TBP, encoded by ORF24 in KSHV, makes a direct protein-protein contact with the C-terminal domain of host RNA polymerase II (Pol II), which is a unique feature that functionally distinguishes viral from cellular TBP. The interaction is mediated by the N-terminal domain (NTD) of ORF24 through a conserved motif that is shared in its ß- and γ-herpesvirus homologs. Thus, these herpesviruses employ an unprecedented strategy in eukaryotic transcription, wherein promoter recognition and polymerase recruitment are facilitated by a single transcriptional activator with functionally distinct domains.
Assuntos
Herpesvirus Humano 8/metabolismo , RNA Polimerase II/metabolismo , Proteína de Ligação a TATA-Box/metabolismo , Proteínas Virais/metabolismo , Motivos de Aminoácidos , Células HEK293 , Herpesvirus Humano 8/genética , Humanos , Ligação Proteica , Domínios Proteicos , RNA Polimerase II/genética , Proteína de Ligação a TATA-Box/genética , Proteínas Virais/genéticaAssuntos
COVID-19 , RNA Viral , SARS-CoV-2 , SARS-CoV-2/imunologia , SARS-CoV-2/genética , Humanos , RNA Viral/genética , RNA Viral/imunologia , COVID-19/imunologia , COVID-19/virologia , Núcleo Celular/metabolismo , Núcleo Celular/virologia , Proteínas não Estruturais Virais/imunologia , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismo , Evasão da Resposta ImuneRESUMO
Transcription and RNA decay are key determinants of gene expression; these processes are typically considered as the uncoupled beginning and end of the messenger RNA (mRNA) lifecycle. Here we describe the growing number of studies demonstrating interplay between these spatially disparate processes in eukaryotes. Specifically, cells can maintain mRNA levels by buffering against changes in mRNA stability or transcription, and can also respond to virally induced accelerated decay by reducing RNA polymerase II gene expression. In addition to these global responses, there is also evidence that mRNAs containing a premature stop codon can cause transcriptional upregulation of homologous genes in a targeted fashion. In each of these systems, RNA binding proteins (RBPs), particularly those involved in mRNA degradation, are critical for cytoplasmic to nuclear communication. Although their specific mechanistic contributions are yet to be fully elucidated, differential trafficking of RBPs between subcellular compartments are likely to play a central role in regulating this gene expression feedback pathway.
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Citoplasma/genética , Estabilidade de RNA/genética , RNA Mensageiro/genética , Transcrição Gênica , Animais , Núcleo Celular/genética , Núcleo Celular/metabolismo , Códon de Terminação/genética , Citoplasma/metabolismo , Exorribonucleases/metabolismo , Expressão Gênica , Homeostase/genética , Humanos , Infecções/genética , Proteínas Associadas aos Microtúbulos/metabolismo , RNA Polimerase II/genética , RNA Polimerase II/metabolismo , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/genéticaRESUMO
Few human pathogens have been the focus of as much concentrated worldwide attention as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of COVID-19. Its emergence into the human population and ensuing pandemic came on the heels of severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV), two other highly pathogenic coronavirus spillovers, which collectively have reshaped our view of a virus family previously associated primarily with the common cold. It has placed intense pressure on the collective scientific community to develop therapeutics and vaccines, whose engineering relies on a detailed understanding of coronavirus biology. Here, we present the molecular virology of coronavirus infection, including its entry into cells, its remarkably sophisticated gene expression and replication mechanisms, its extensive remodeling of the intracellular environment, and its multifaceted immune evasion strategies. We highlight aspects of the viral life cycle that may be amenable to antiviral targeting as well as key features of its biology that await discovery.
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Infecções por Coronavirus/virologia , Coronavirus/fisiologia , Regulação Viral da Expressão Gênica , Fenômenos Fisiológicos Virais , Animais , Antígenos Virais/imunologia , Coronavirus/genética , Coronavirus/imunologia , Infecções por Coronavirus/genética , Infecções por Coronavirus/imunologia , Interações Hospedeiro-Patógeno , HumanosRESUMO
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease commonly treated with riluzole, a small molecule that may act via modulation of glutamatergic neurotransmission. However, riluzole only modestly extends lifespan for people living with ALS, and its precise mechanisms of action remain unclear. Most ALS cases are characterised by accumulation of cytoplasmic TAR DNA binding protein of 43 kDa (TDP-43), and understanding the effects of riluzole in models that closely recapitulate TDP-43 pathology may provide insights for development of improved therapeutics. We therefore investigated the effects of riluzole in female transgenic mice that inducibly express nuclear localisation sequence (NLS)-deficient human TDP-43 in neurons (NEFH-tTA/tetO-hTDP-43ΔNLS, 'rNLS8', mice). Riluzole treatment from the first day of hTDP-43ΔNLS expression did not alter disease onset, weight loss or performance on multiple motor behavioural tasks. Riluzole treatment also did not alter TDP-43 protein levels, solubility or phosphorylation. Although we identified a significant decrease in GluA2 and GluA3 proteins in the cortex of rNLS8 mice, riluzole did not ameliorate this disease-associated molecular phenotype. Likewise, riluzole did not alter the disease-associated atrophy of hindlimb muscle in rNLS8 mice. Finally, riluzole treatment beginning after disease onset in rNLS8 mice similarly had no effect on progression of late-stage disease or animal survival. Together, we demonstrate specific glutamatergic receptor alterations and muscle fibre-type changes reminiscent of ALS in female rNLS8 mice, but riluzole had no effect on these or any other disease phenotypes. Future targeting of pathways related to accumulation of TDP-43 pathology may be needed to develop better treatments for ALS.
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Esclerose Lateral Amiotrófica , Doenças Neurodegenerativas , Esclerose Lateral Amiotrófica/tratamento farmacológico , Animais , Proteínas de Ligação a DNA/genética , Modelos Animais de Doenças , Feminino , Camundongos , Camundongos Transgênicos , Riluzol/farmacologia , Riluzol/uso terapêuticoRESUMO
Short interspersed nuclear elements (SINEs) are RNA polymerase III (RNAPIII)-transcribed, retrotransposable noncoding RNA (ncRNA) elements ubiquitously spread throughout mammalian genomes. While normally silenced in healthy somatic tissue, SINEs can be induced during infection with DNA viruses, including the model murine gammaherpesvirus 68 (MHV68). Here, we explored the mechanisms underlying MHV68 activation of SINE ncRNAs. We demonstrate that lytic MHV68 infection of B cells, macrophages, and fibroblasts leads to robust activation of the B2 family of SINEs in a cell-autonomous manner. B2 ncRNA induction requires neither host innate immune signaling factors nor involvement of the RNAPIII master regulator Maf1. However, we identified MHV68 ORF36, the conserved herpesviral kinase, as playing a key role in B2 induction during lytic infection. SINE activation is linked to ORF36 kinase activity and can also be induced by inhibition of histone deacetylases 1 and 2 (HCAC 1/2), which is one of the known ORF36 functions. Collectively, our data suggest that ORF36-mediated changes in chromatin modification contribute to B2 activation during MHV68 infection and that this activity is conserved in other herpesviral protein kinase homologs.IMPORTANCE Viral infection dramatically changes the levels of many types of RNA in a cell. In particular, certain oncogenic viruses activate expression of repetitive genes called retrotransposons, which are normally silenced due to their ability to copy and spread throughout the genome. Here, we established that infection with the gammaherpesvirus MHV68 leads to a dramatic induction of a class of noncoding retrotransposons called B2 SINEs in multiple cell types. We then explored how MHV68 activates B2 SINEs, revealing a role for the conserved herpesviral protein kinase ORF36. Both ORF36 kinase-dependent and kinase-independent functions contribute to B2 induction, perhaps through ORF36 targeting of proteins involved in controlling the accessibility of chromatin surrounding SINE loci. Understanding the features underlying induction of these elements following MHV68 infection should provide insight into core elements of SINE regulation, as well as disregulation of SINE elements associated with disease.
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Infecções por Herpesviridae/enzimologia , Proteínas Quinases/metabolismo , Retroelementos , Rhadinovirus/enzimologia , Proteínas Virais/metabolismo , Animais , Linfócitos B/enzimologia , Linfócitos B/patologia , Linfócitos B/virologia , Infecções por Herpesviridae/genética , Infecções por Herpesviridae/patologia , Histona Desacetilase 1/genética , Histona Desacetilase 1/metabolismo , Histona Desacetilase 2/genética , Histona Desacetilase 2/metabolismo , Macrófagos/enzimologia , Macrófagos/patologia , Macrófagos/virologia , Camundongos , Células NIH 3T3 , Proteínas Quinases/genética , RNA não Traduzido/genética , RNA não Traduzido/metabolismo , Rhadinovirus/genética , Proteínas Virais/genéticaRESUMO
Late gene transcription in the beta- and gammaherpesviruses depends on a set of virally encoded transcriptional activators (vTAs) that hijack the host transcriptional machinery and direct it to a subset of viral genes that are required for completion of the viral replication cycle and capsid assembly. In Kaposi's sarcoma-associated herpesvirus (KSHV), these vTAs are encoded by ORF18, ORF24, ORF30, ORF31, ORF34, and ORF66. Assembly of the vTAs into a complex is critical for late gene transcription, and thus, deciphering the architecture of the complex is central to understanding its transcriptional regulatory activity. Here, we generated an ORF66-null virus and confirmed that it fails to produce late genes and infectious virions. We show that ORF66 is incorporated into the vTA complex primarily through its interaction with ORF34, which is dependent upon a set of four conserved cysteine-rich motifs in the C-terminal domain of ORF66. While both ORF24 and ORF66 occupy the canonical K8.1 late gene promoter, their promoter occupancy requires the presence of the other vTAs, suggesting that sequence-specific, stable binding requires assembly of the entire complex on the promoter. Additionally, we found that ORF24 expression is impaired in the absence of a stable vTA complex. This work extends our knowledge about the architecture of the KSHV viral preinitiation complex and suggests that it functions as a complex to recognize late gene promoters.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV; human herpesvirus 8) is an oncogenic gammaherpesvirus that is the causative agent of multiple human cancers. The release of infectious virions requires the production of capsid proteins and other late genes, whose production is transcriptionally controlled by a complex of six virally encoded proteins that hijack the host transcription machinery. It is poorly understood how this complex assembles or what function five of its six components play in transcription. Here, we demonstrate that ORF66 is an essential component of this complex in KSHV and that its inclusion in the complex depends upon its C-terminal domain, which contains highly conserved cysteine-rich motifs reminiscent of zinc finger motifs. Additionally, we examined the assembly of the viral preinitiation complex at late gene promoters and found that while sequence-specific binding of late gene promoters requires ORF24, it additionally requires a fully assembled viral preinitiation complex.
Assuntos
Regulação Viral da Expressão Gênica/fisiologia , Herpesvirus Humano 8/metabolismo , Fases de Leitura Aberta , Regiões Promotoras Genéticas , Proteínas Virais/metabolismo , Motivos de Aminoácidos , Células HEK293 , Herpesvirus Humano 8/genética , Humanos , Domínios Proteicos , Proteínas Virais/genéticaRESUMO
In the beta- and gammaherpesviruses, a specialized complex of viral transcriptional activators (vTAs) coordinate to direct expression of virus-encoded late genes, which are critical for viral assembly and whose transcription initiates only after the onset of viral DNA replication. The vTAs in Kaposi's sarcoma-associated herpesvirus (KSHV) are ORF18, ORF24, ORF30, ORF31, ORF34, and ORF66. While the general organization of the vTA complex has been mapped, the individual roles of these proteins and how they coordinate to activate late gene promoters remain largely unknown. Here, we performed a comprehensive mutational analysis of the conserved residues in ORF18, which is a highly interconnected vTA component. Surprisingly, the mutants were largely selective for disrupting the interaction with ORF30 but not the other three ORF18 binding partners. Furthermore, disrupting the ORF18-ORF30 interaction weakened the vTA complex as a whole, and an ORF18 point mutant that failed to bind ORF30 was unable to complement an ORF18 null virus. Thus, contacts between individual vTAs are critical as even small disruptions in this complex result in profound defects in KSHV late gene expression.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of Kaposi's sarcoma and other B-cell cancers and remains a leading cause of death in immunocompromised individuals. A key step in the production of infectious virions is the transcription of viral late genes, which generates capsid and structural proteins and requires the coordination of six viral proteins that form a complex. The role of these proteins during transcription complex formation and the importance of protein-protein interactions are not well understood. Here, we focused on a central component of the complex, ORF18, and revealed that disruption of its interaction with even a single component of the complex (ORF30) prevents late gene expression and completion of the viral lifecycle. These findings underscore how individual interactions between the late gene transcription components are critical for both the stability and function of the complex.