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1.
Autoimmun Rev ; 22(6): 103323, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36940841

RESUMEN

PURPOSE: To investigate the role of non-pharmaceutical therapies on disease activity in rheumatoid arthritis through systematic review and meta-analysis. METHODS: A review of Pubmed, EMBASE, Web of Science, and the Cochrane Library was performed from inception until March 26, 2019. Only randomized controlled trials which assessed oral, non-pharmacological interventions (e.g. diets, vitamins, oils, herbal remedies, fatty acids, supplements, etc.) in adult patients with rheumatoid arthritis, that presented clinically-relevant outcomes (defined as pain, fatigue, disability, joint counts, and/or disease indices) were included in our meta-analysis. Data were analyzed as mean differences between active and placebo and forest plots were performed. Heterogeneity was evaluated using I-squared statistics while funnel plots and Cochrane's risk of bias assessment evaluated bias. RESULTS: 8170 articles were identified in the search and 51 were RCTs were included. The mean difference in DAS28 was significantly improved in experimental group treated with diet (-0.46 [-0.91, -0.02], p = 0.04), zinc sulfate, copper sulphate, selenium, potassium, lipoic acid, turmeric, pomegranate extract, chamomile, and cranberry extract supplements (-0.77 [-1.17, -0.38], p < 0.001), A, B6, C, D, E, and K vitamins (-0.52 [-0.74, -0.29], p < 0.001), and fatty acids (-0.19 [-0.36, -0.01], p = 0.03). Other clinical metrics such as SJC, TJC, HAQ, SDAI, ACR20, and self-reported pain were decreased in the treatment groups. There was significant reporting bias in the studies. CONCLUSION: Some non-pharmacological therapies may modestly improve some clinical outcomes in patients with rheumatoid arthritis. Many identified studies lacked full reporting. Further clinical trials that are well-designed, adequately powered, and sufficiently report ACR improvement criteria or EULAR response criteria outcomes are needed to confirm the efficacy of these therapies.


Asunto(s)
Artritis Reumatoide , Adulto , Humanos , Artritis Reumatoide/tratamiento farmacológico , Dolor , Suplementos Dietéticos , Vitaminas/uso terapéutico , Ácidos Grasos/uso terapéutico
2.
Cells ; 11(5)2022 02 26.
Artículo en Inglés | MEDLINE | ID: mdl-35269443

RESUMEN

The phosphoinositide-3-kinase (PI3K)/AKT pathway regulates cell survival and is over-activated in most human cancers, including ovarian cancer. Following growth factor stimulation, AKT1 is activated by phosphorylation at T308 and S473. Disruption of the AKT1 signaling pathway is sufficient to inhibit the epithelial-mesenchymal transition in epithelial ovarian cancer (EOC) cells. In metastatic disease, adherent EOC cells transition to a dormant spheroid state, characterized previously by low S473 phosphorylation in AKT1. We confirmed this finding and observed that T308 phosphorylation was yet further reduced in EOC spheroids and that the transition from adherent to spheroid growth is accompanied by significantly increased levels of let-7 miRNAs. We then used mechanistic studies to investigate the impact of let-7 miRNAs on AKT1 phosphorylation status and activity in cells. In growth factor-stimulated HEK 293T cells supplemented with let-7a, we found increased phosphorylation of AKT1 at T308, decreased phosphorylation at S473, and enhanced downstream AKT1 substrate GSK-3ß phosphorylation. Let-7b and let-7g also deregulated AKT signaling by rendering AKT1 insensitive to growth factor simulation. We uncovered let-7a-dependent deregulation of PI3K pathway components, including PI3KC2A, PDK1, and RICTOR, that govern AKT1 phosphorylation and activity. Together, our data show a new role for miRNAs in regulating AKT signaling.


Asunto(s)
MicroARNs , Neoplasias Ováricas , Carcinoma Epitelial de Ovario , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Humanos , MicroARNs/genética , MicroARNs/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-akt/metabolismo
3.
Clin Exp Rheumatol ; 39 Suppl 132(5): 94-101, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34596037

RESUMEN

OBJECTIVES: Children and adults may develop Behçet's disease (BD), often with ocular involvement such as uveitis. This study aimed to determine the prevalence and type of ocular manifestations in childhood and adult BD. METHODS: Medline, Web of Science and Cochrane databases were searched from inception to October 5, 2018 to identify publications related to Behçet's disease comprising minimum twenty patients and providing the frequency of ocular manifestations (OC). Random effects models were used to combine the prevalence of OC in adults and children with BD. Heterogeneity was evaluated using I2. RESULTS: The search resulted in 3129 articles, of which 51 were included in meta-analysis. OCs were slightly more frequent in childhood onset BD with the mean [95% Confidence Interval] frequency of 45 [34-56%] compared to 36 [29-43%] in adults, however, this difference was not statistically significant (p=0.198). In both children and adults, posterior uveitis (children 27% vs. adults 25%, and retinal vasculitis in adults 16%) was the most common ocular manifestation, followed by anterior uveitis (children 18% vs. adults 23%). When comparing the distribution of OC in Behcet's in adults, there was geographic variation where OC were higher in Turkey and the Middle East 42%, followed by Europe and North America (36%), North Africa 26% and East Asia 25% but not significantly (p=0.27). CONCLUSIONS: Ocular manifestations, predominantly uveitis; are common in BD. Ocular manifestations are not proportionately more frequent in adults with BD along the ancient Silk Road.


Asunto(s)
Síndrome de Behçet , Vasculitis Retiniana , Uveítis Posterior , Uveítis , Adulto , Síndrome de Behçet/diagnóstico , Síndrome de Behçet/epidemiología , Niño , Humanos , Prevalencia , Uveítis/epidemiología , Uveítis/etiología
4.
Sci Rep ; 11(1): 10474, 2021 05 18.
Artículo en Inglés | MEDLINE | ID: mdl-34006854

RESUMEN

To evaluate the effects of alcohol consumption on disease activity in rheumatoid arthritis. EMBASE, Pubmed, the Cochrane Library, and Web of Science were searched until July 29, 2020. English language studies that reported disease activity outcomes in rheumatoid arthritis were included. Studies were excluded if they were reviews, case reports, had fewer than 20 patients, or reported on prevalence but not disease activity in RA. Forest plots were used to determine pooled mean difference and were generated on RevMan5.3. Linear regression was used to determine correlations between alcohol and antibody status, gender, and smoking status. The search identified 4126 citations of which 14 were included. The pooled mean difference in DAS28 (95% CI) was 0.34 (0.24, 0.44) (p < 10-5) between drinkers and non-drinkers with lower DAS28 in non-drinkers, 0.33 (0.05, 0.62) (p = 0.02) between heavy drinkers and non-drinkers with lower DAS28 in heavy drinkers, and 0.00 (- 0.30, 0.30) (p = 0.98) between low- and high-risk drinkers. The mean difference of HAQ assessments was significantly different between those who drink alcohol compared to those who do not, with drinkers reporting lower HAQ scores (0.3 (0.18, 0.41), p < 10-5). There was no significant correlation between drinking and gender, smoking status, or antibody positivity. Alcohol consumption is associated with lower disease activity and self-reported health assessment in rheumatoid arthritis. However, drinking has no correlation with smoking, gender, or antibody status.


Asunto(s)
Consumo de Bebidas Alcohólicas , Artritis Reumatoide/patología , Evaluación de Resultado en la Atención de Salud , Estudios de Casos y Controles , Femenino , Humanos , Masculino
5.
J Rheumatol ; 48(11): 1698-1717, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-33993109

RESUMEN

OBJECTIVE: Systemic sclerosis (SSc) is a multisystem disease with heterogeneity in presentation and prognosis.An international collaboration to develop new SSc subset criteria is underway. Our objectives were to identify systems of SSc subset classification and synthesize novel concepts to inform development of new criteria. METHODS: Medline, Cochrane MEDLINE, the Cumulative Index to Nursing and Allied Health Literature, EMBASE, and Web of Science were searched from their inceptions to December 2019 for studies related to SSc subclassification, limited to humans and without language or sample size restrictions. RESULTS: Of 5686 citations, 102 studies reported original data on SSc subsets. Subset classification systems relied on extent of skin involvement and/or SSc-specific autoantibodies (n = 61), nailfold capillary patterns (n = 29), and molecular, genomic, and cellular patterns (n = 12). While some systems of subset classification confer prognostic value for clinical phenotype, severity, and mortality, only subsetting by gene expression signatures in tissue samples has been associated with response to therapy. CONCLUSION: Subsetting on extent of skin involvement remains important. Novel disease attributes including SSc-specific autoantibodies, nailfold capillary patterns, and tissue gene expression signatures have been proposed as innovative means of SSc subsetting.


Asunto(s)
Esclerodermia Sistémica , Autoanticuerpos , Humanos , Fenotipo , Pronóstico , Esclerodermia Sistémica/diagnóstico
7.
J Rheumatol ; 48(1): 25-34, 2021 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-32358156

RESUMEN

OBJECTIVE: Rheumatoid arthritis (RA) and other rheumatic diseases may present with ocular manifestations.The purpose of our work was to determine the prevalence and type of eye involvement in RA and other connective tissue diseases through a metaanalysis and literature review. METHODS: A systematic review of the literature was performed using Medline, Web of Science, and the Cochrane Library from their inceptions until January 7, 2019. Conjunctivitis, keratoconjunctivitis sicca, xeropthalmia, uveitis, eye hemorrhage, optic neuritis, papilledema, orbital disease, retinal artery/vein occlusion, macular edema, retinitis, chorioretinitis, scleritis, iridocyclitits, choroid hemorrhage, blindness, and amaurosis fugax were searched for prevalence in patients with RA, systemic lupus erythematosus (SLE), antiphospholipid syndrome (APS), dermatomyositis, polymyositis, systemic sclerosis, Sjögren syndrome (SS), undifferentiated connective tissue disease, giant cell arteritis, granulomatosis polyangiitis (GPA; formerly Wegener granulomatosis), systemic vasculitis, and sarcoidosis. RESULTS: There were 3394 studies identified and 65 included. The prevalence of eye involvement was 18% in RA, 26% in GPA, 27% in giant cell arteritis, 27% in sarcoidosis, 31% in SLE, and 35% in APS. The most common manifestation was dry eye syndrome ("dry eye"; keratoconjunctivitis sicca) in most diseases analyzed, with an especially high frequency of 89% in SS. Anterior and posterior uveitis were the most common ocular complications in sarcoidosis, occurring in 16% (95% CI 3-28) and 6% (95% CI 3-9) of patients, respectively. CONCLUSION: Eye involvement is present in approximately one-fifth of patients with RA, and a one-quarter to one-third of patients with connective tissue diseases (other than SS at 89%) and vasculitis.


Asunto(s)
Artritis Reumatoide , Enfermedades del Tejido Conjuntivo , Granulomatosis con Poliangitis , Lupus Eritematoso Sistémico , Enfermedades Reumáticas , Artritis Reumatoide/complicaciones , Artritis Reumatoide/epidemiología , Enfermedades del Tejido Conjuntivo/complicaciones , Enfermedades del Tejido Conjuntivo/epidemiología , Humanos
8.
Clin Exp Rheumatol ; 39(2): 407-412, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33124575

RESUMEN

OBJECTIVES: The purpose of this systematic review was to identify existing guidelines for antimalarial prescribing and monitoring, specifically for hydroxychloroquine, and how these guidelines compare and have evolved over time. METHODS: A literature search was conducted using Embase and Medline to identify guidelines published from 1946-2018. MeSH terms were used and alternative spelling and related words were entered as keywords to broaden results. RESULTS: 243 results were reviewed to obtain 11 recommendations. Ophthalmology sources included the American Academy of Ophthalmology, Royal College of Ophthalmologists and Canadian editorials. The American College of Rheumatology and Canadian Rheumatology Association consensus statements summarised rheumatology recommendations. Recently, American and British guidelines changed from suggesting hydroxychloroquine doses ≤6.5 mg/kg/day to ≤5 mg/kg/day. American guidelines recommended baseline visual field (VF) testing and annual screening after five years. Visual field (VF) testing evolved from the Amsler grid to current recommendations of 10-2 automated VF and spectral-domain optical coherence tomography (SD-OCT). The 2012 Canadian recommendations suggested initial VF testing every two years, with SD-OCT after 10 years. Older British guidelines advocated for baseline and annual assessment with Amsler grids during rheumatology clinic visits. The 2018 British guidelines supported baseline and annual screening after five years with 10-2 VF, SD-OCT and fundus autofluorescence. CONCLUSIONS: The newest recommendations are heterogeneous suggesting lower hydroxychloroquine dosing. Retinal toxicity is irreversible and the risk increases over time. Annual screening after five years with automated VF and SD-OCT may be warranted to detect early changes and discontinue therapy if necessary.


Asunto(s)
Antimaláricos , Antirreumáticos , Enfermedades de la Retina , Enfermedades Reumáticas , Antimaláricos/efectos adversos , Antirreumáticos/efectos adversos , Canadá , Humanos , Hidroxicloroquina/efectos adversos , Enfermedades de la Retina/inducido químicamente , Enfermedades de la Retina/diagnóstico , Enfermedades Reumáticas/diagnóstico , Enfermedades Reumáticas/tratamiento farmacológico , Tomografía de Coherencia Óptica
10.
Autoimmun Rev ; 19(9): 102602, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32659476

RESUMEN

BACKGROUND: Pulmonary arterial hypertension (PAH) in systemic sclerosis (SSc) is a lethal complication affecting 8-15% of patients. Screening tests such as echocardiography and pulmonary function tests allow for triaging patients for diagnosis by right heart catheterization. Understanding risk factors of SSc-PAH could help differentiate high-risk patients. METHODS: A systematic review was conducted to determine associations with SSc-PAH, including clinical/disease characteristics, antibodies, labs and biomarkers. The frequencies of publications featuring each risk/association were reported. RESULTS: Among 2654 articles, 984 duplicates and 1578 irrelevant articles were removed, leaving 92 articles for manual screening. After excluding 55 papers with small sample sizes, publications from identical cohorts, not English language, or PAH not ascertained by RHC, 37 articles were eligible. A total of 43 factors for SSc-PAH were identified within seven categories. Several associations were due to PAH and risk factors such as dynpnea, right heart failure, and short 6-minute walk distance. Patient characteristics (14), pulmonary physiology (6), antibody profiles (6) and genetics/epigenetics (6) had the most numerous and diverse factors, while biomarkers (4) and other labs (2) features were infrequent. Low carbon monoxide (DLCO) (6), older age (4), longer disease duration (4), positive anticentromere antibodies (ACA) (4), telangiectasias (4), high brain natriuretic peptide (4) were frequent associations. CONCLUSIONS: Risk factors for SSc-PAH such as ACA, older age, longer disease duration limited cutaneous SSc subset and presence of ILD may enrich screening programs. Genes and other antibody profiles are inconsistent and requires further validation.


Asunto(s)
Hipertensión Arterial Pulmonar , Esclerodermia Sistémica , Envejecimiento , Humanos , Péptido Natriurético Encefálico , Hipertensión Arterial Pulmonar/genética , Hipertensión Arterial Pulmonar/inmunología , Factores de Riesgo , Esclerodermia Sistémica/genética , Esclerodermia Sistémica/inmunología
11.
Joint Bone Spine ; 86(6): 685-690, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31207292

RESUMEN

OBJECTIVES: This meta-analysis investigated the frequency and type of ocular involvement in juvenile inflammatory arthritis (JIA) and other juvenile rheumatic diseases. METHODS: Medline, Web of Science and Cochrane databases were searched from inception to September 2018 to identify publications related to juvenile arthritis and rheumatic diseases, which reported frequency of Uveitis in juvenile rheumatic conditions and contained at least 20 patients. The prevalence and type of eye complications were extracted, and random effects models estimated their frequency. Heterogeneity was evaluated using I2. RESULTS: In total, 7132 unique citations resulted in 59 articles included. Pooled frequency of uveitis was: 24% in oligoarticular JIA, 12% in polyarticular JIA, 1% in systemic JIA, 50% in pediatric Bechet's, 9% in juvenile psoriatic arthritis, 24% in juvenile spondyloarthropathy and 5% in juvenile systemic lupus erythematosus. The most common uveitis in JIA was anterior uveitis, which occurred in 14%; also described as iridocyclitis in 10% of patients. Publication bias was negligible for all conditions except those with few reported studies (juvenile SLE and systemic JIA). Uveitis in JIA was more common in Europe (14%), North America (11%) and the Middle East (12%) than East Asia (7%) and Oceania (3%). CONCLUSIONS: Ocular involvement (mostly uveitis) in juvenile inflammatory arthritis and other pediatric rheumatic diseases varied between 3% and 50% depending on the underlying condition; and was highest in pediatric Bechet's. In JIA, the highest frequency of uveitis was in oligoarticular JIA; with anterior uveitis being the most frequent type of uveitis. There was variation geographically for uveitis in JIA.


Asunto(s)
Artritis Juvenil/diagnóstico , Artritis Juvenil/epidemiología , Uveítis/diagnóstico , Uveítis/epidemiología , Adolescente , Distribución por Edad , Niño , Comorbilidad , Bases de Datos Factuales , Femenino , Humanos , Masculino , Ontario/epidemiología , Prevalencia , Pronóstico , Medición de Riesgo , Índice de Severidad de la Enfermedad , Distribución por Sexo
12.
Clin Rheumatol ; 38(8): 2083-2088, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-30919146

RESUMEN

OBJECTIVE: To characterize rheumatologists' perspectives on evolving trends of reactive arthritis (ReA). METHODS: After ethics approval, 548 members of the Canadian Rheumatology Association were surveyed with 37 questions covering their demographic information, subspecialty, level of experience, practice setting and opinions on prevalence, treatment, and causes of ReA. Results were analyzed with descriptive statistics. RESULTS: Ninety-seven responded to the survey (18% response rate); 66 fully completed it. Nearly half of respondents believed that the incidence of ReA is declining and causes of ReA may be changing. Physicians reported that most of the ReA cases in their practices were caused by an unknown organism, sexually transmitted, or gastrointestinal infection. Full triad ReA increased the chance of recurrence according to their impressions. Common investigations in ReA included inflammatory markers, HLA-B27, chlamydia and gonorrhea testing, stool cultures, synovial fluid analyses, SI joint imaging. ReA treatment included NSAIDs, intra-articular corticosteroid injections, and DMARDs. Two-thirds said they used TNF alpha inhibitors in chronic ReA occasionally or more frequently. CONCLUSION: ReA may be decreasing in frequency and severity in Canada. Changes could be due to less food borne illness, cleaner water, or more rapid treatment of sexually transmitted infections. The cause is often unknown in clinical practice.Key Points• Reactive arthritis (ReA) is likely decreasing in prevalence and severity.• Patients with classic trial of arthritis, urethritis, and conjunctivitis are more likely to have recurrent and/or chronic ReA.• The causal organisms are often not detected and seem to be changing over time.


Asunto(s)
Artritis Reactiva/epidemiología , Artritis Reactiva/terapia , Reumatología/tendencias , Corticoesteroides/uso terapéutico , Antiinflamatorios no Esteroideos/uso terapéutico , Antirreumáticos/uso terapéutico , Artritis Reactiva/diagnóstico , Canadá/epidemiología , Femenino , Enfermedades Gastrointestinales/complicaciones , Antígeno HLA-B27/análisis , Humanos , Infecciones/complicaciones , Inflamación , Masculino , Médicos , Pautas de la Práctica en Medicina , Prohibitinas , Enfermedades de Transmisión Sexual/complicaciones , Sociedades Médicas
13.
Nucleic Acids Res ; 47(6): 3045-3057, 2019 04 08.
Artículo en Inglés | MEDLINE | ID: mdl-30715470

RESUMEN

Uridylation-dependent RNA decay is a widespread eukaryotic pathway modulating RNA homeostasis. Terminal uridylyltransferases (Tutases) add untemplated uridyl residues to RNA 3'-ends, marking them for degradation by the U-specific exonuclease Dis3L2. In Schizosaccharomyces pombe, Cid1 uridylates a variety of RNAs. In this study, we investigate the prevalence and impact of uridylation-dependent RNA decay in S. pombe by transcriptionally profiling cid1 and dis3L2 deletion strains. We found that the exonuclease Dis3L2 represents a bottleneck in uridylation-dependent mRNA decay, whereas Cid1 plays a redundant role that can be complemented by other Tutases. Deletion of dis3L2 elicits a cellular stress response, upregulating transcription of genes involved in protein folding and degradation. Misfolded proteins accumulate in both deletion strains, yet only trigger a strong stress response in dis3L2 deficient cells. While a deletion of cid1 increases sensitivity to protein misfolding stress, a dis3L2 deletion showed no increased sensitivity or was even protective. We furthermore show that uridylyl- and adenylyltransferases cooperate to generate a 5'-NxAUUAAAA-3' RNA motif on dak2 mRNA. Our studies elucidate the role of uridylation-dependent RNA decay as part of a global mRNA surveillance, and we found that perturbation of this pathway leads to the accumulation of misfolded proteins and elicits cellular stress responses.


Asunto(s)
ARN Nucleotidiltransferasas/genética , Estabilidad del ARN/genética , Proteínas de Schizosaccharomyces pombe/genética , Schizosaccharomyces/genética , Exorribonucleasas/genética , Complejo Multienzimático de Ribonucleasas del Exosoma/genética , Nucleotidiltransferasas/genética , ARN de Hongos/genética , ARN Mensajero/genética , Uridina/genética
14.
Genes (Basel) ; 9(6)2018 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-29921790

RESUMEN

microRNA (miRNA) activity and regulation are of increasing interest as new therapeutic targets. Traditional approaches to assess miRNA levels in cells rely on RNA sequencing or quantitative PCR. While useful, these approaches are based on RNA extraction and cannot be applied in real-time to observe miRNA activity with single-cell resolution. We developed a green fluorescence protein (GFP)-based reporter system that allows for a direct, real-time readout of changes in miRNA activity in live cells. The miRNA activity reporter (MiRAR) consists of GFP fused to a 3′ untranslated region containing specific miRNA binding sites, resulting in miRNA activity-dependent GFP expression. Using qPCR, we verified the inverse relationship of GFP fluorescence and miRNA levels. We demonstrated that this novel optogenetic reporter system quantifies cellular levels of the tumor suppressor miRNA let-7 in real-time in single Human embryonic kidney 293 (HEK 293) cells. Our data shows that the MiRAR can be applied to detect changes in miRNA levels upon disruption of miRNA degradation pathways. We further show that the reporter could be adapted to monitor another disease-relevant miRNA, miR-122. With trivial modifications, this approach could be applied across the miRNome for quantification of many specific miRNA in cell cultures, tissues, or transgenic animal models.

15.
RNA Biol ; 15(4-5): 567-575, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-28933646

RESUMEN

High-fidelity translation and a strictly accurate proteome were originally assumed as essential to life and cellular viability. Yet recent studies in bacteria and eukaryotic model organisms suggest that proteome-wide mistranslation can provide selective advantages and is tolerated in the cell at higher levels than previously thought (one error in 6.9 × 10-4 in yeast) with a limited impact on phenotype. Previously, we selected a tRNAPro containing a single mutation that induces mistranslation with alanine at proline codons in yeast. Yeast tolerate the mistranslation by inducing a heat-shock response and through the action of the proteasome. Here we found a homologous human tRNAPro (G3:U70) mutant that is not aminoacylated with proline, but is an efficient alanine acceptor. In live human cells, we visualized mistranslation using a green fluorescent protein reporter that fluoresces in response to mistranslation at proline codons. In agreement with measurements in yeast, quantitation based on the GFP reporter suggested a mistranslation rate of up to 2-5% in HEK 293 cells. Our findings suggest a stress-dependent phenomenon where mistranslation levels increased during nutrient starvation. Human cells did not mount a detectable heat-shock response and tolerated this level of mistranslation without apparent impact on cell viability. Because humans encode ∼600 tRNA genes and the natural population has greater tRNA sequence diversity than previously appreciated, our data also demonstrate a cell-based screen with the potential to elucidate mutations in tRNAs that may contribute to or alleviate disease.


Asunto(s)
Alanina/metabolismo , Aminoacil-ARNt Sintetasas/genética , Mutación , Prolina/metabolismo , Biosíntesis de Proteínas , Procesamiento Postranscripcional del ARN , ARN de Transferencia de Prolina/genética , Alanina/genética , Aminoacil-ARNt Sintetasas/metabolismo , Aminoacilación , Anticodón/química , Anticodón/metabolismo , Supervivencia Celular/efectos de los fármacos , Codón/química , Codón/metabolismo , Medios de Cultivo/farmacología , Escherichia coli/genética , Escherichia coli/metabolismo , Genes Reporteros , Glucosa/deficiencia , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Células HEK293 , Humanos , Plásmidos/química , Plásmidos/metabolismo , Prolina/genética , Complejo de la Endopetidasa Proteasomal/metabolismo , ARN de Transferencia de Prolina/metabolismo , Transfección
16.
RNA Biol ; 15(4-5): 614-622, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-28901837

RESUMEN

tRNAHis guanylyltransferase (Thg1) has unique reverse (3'-5') polymerase activity occurring in all three domains of life. Most eukaryotic Thg1 homologs are essential genes involved in tRNAHis maturation. These enzymes normally catalyze a single 5' guanylation of tRNAHis lacking the essential G-1 identity element required for aminoacylation. Recent studies suggest that archaeal type Thg1, which includes most archaeal and bacterial Thg1 enzymes is phylogenetically distant from eukaryotic Thg1. Thg1 is evolutionarily related to canonical 5'-3' forward polymerases but catalyzes reverse 3'-5'polymerization. Similar to its forward polymerase counterparts, Thg1 encodes the conserved catalytic palm domain and fingers domain. Here we investigate the minimal requirements for reverse polymerization. We show that the naturally occurring minimal Thg1 enzyme from Ignicoccus hospitalis (IhThg1), which lacks parts of the conserved fingers domain, is catalytically active. And adds all four natural nucleotides to RNA substrates, we further show that the entire fingers domain of Methanosarcina acetivorans Thg1 and Pyrobaculum aerophilum Thg1 (PaThg1) is dispensable for enzymatic activity. In addition, we identified residues in yeast Thg1 that play a part in preventing extended polymerization. Mutation of these residues with alanine resulted in extended reverse polymerization. PaThg1 was found to catalyze extended, template dependent tRNA repair, adding up to 13 nucleotides to a truncated tRNAHis substrate. Sequencing results suggest that PaThg1 fully restored the near correct sequence of the D- and acceptor stem, but also produced incompletely and incorrectly repaired tRNA products. This research forms the basis for future engineering efforts towards a high fidelity, template dependent reverse polymerase.


Asunto(s)
Desulfurococcaceae/enzimología , Methanosarcina/enzimología , Nucleotidiltransferasas/metabolismo , Pyrobaculum/enzimología , ARN de Transferencia de Histidina/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/enzimología , Secuencia de Aminoácidos , Sitios de Unión , Dominio Catalítico , Secuencia Conservada , Desulfurococcaceae/genética , Expresión Génica , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/metabolismo , Cinética , Methanosarcina/genética , Modelos Moleculares , Mutación , Nucleotidiltransferasas/química , Nucleotidiltransferasas/genética , Polimerizacion , Unión Proteica , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Ingeniería de Proteínas/métodos , Pyrobaculum/genética , ARN de Transferencia de Histidina/química , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Alineación de Secuencia , Homología de Secuencia de Aminoácido
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