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1.
Mol Cell ; 84(12): 2337-2352.e9, 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38870935

RESUMO

Ribosome assembly requires precise coordination between the production and assembly of ribosomal components. Mutations in ribosomal proteins that inhibit the assembly process or ribosome function are often associated with ribosomopathies, some of which are linked to defects in proteostasis. In this study, we examine the interplay between several yeast proteostasis enzymes, including deubiquitylases (DUBs) Ubp2 and Ubp14, and E3 ligases Ufd4 and Hul5, and we explore their roles in the regulation of the cellular levels of K29-linked unanchored polyubiquitin (polyUb) chains. Accumulating K29-linked unanchored polyUb chains associate with maturing ribosomes to disrupt their assembly, activate the ribosome assembly stress response (RASTR), and lead to the sequestration of ribosomal proteins at the intranuclear quality control compartment (INQ). These findings reveal the physiological relevance of INQ and provide insights into mechanisms of cellular toxicity associated with ribosomopathies.


Assuntos
Poliubiquitina , Proteínas Ribossômicas , Ribossomos , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Proteínas Ribossômicas/metabolismo , Proteínas Ribossômicas/genética , Ribossomos/metabolismo , Ribossomos/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Poliubiquitina/metabolismo , Poliubiquitina/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitinação , Proteostase , Núcleo Celular/metabolismo
2.
Genes Dev ; 34(1-2): 87-98, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31805522

RESUMO

Replication forks temporarily or terminally pause at hundreds of hard-to-replicate regions around the genome. A conserved pair of budding yeast replisome components Tof1-Csm3 (fission yeast Swi1-Swi3 and human TIMELESS-TIPIN) act as a "molecular brake" and promote fork slowdown at proteinaceous replication fork barriers (RFBs), while the accessory helicase Rrm3 assists the replisome in removing protein obstacles. Here we show that the Tof1-Csm3 complex promotes fork pausing independently of Rrm3 helicase by recruiting topoisomerase I (Top1) to the replisome. Topoisomerase II (Top2) partially compensates for the pausing decrease in cells when Top1 is lost from the replisome. The C terminus of Tof1 is specifically required for Top1 recruitment to the replisome and fork pausing but not for DNA replication checkpoint (DRC) activation. We propose that forks pause at proteinaceous RFBs through a "sTOP" mechanism ("slowing down with topoisomerases I-II"), which we show also contributes to protecting cells from topoisomerase-blocking agents.


Assuntos
Replicação do DNA/genética , DNA Topoisomerases/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Ciclo Celular/metabolismo , DNA Helicases/metabolismo , DNA Topoisomerases Tipo I/metabolismo , Proteínas de Ligação a DNA/metabolismo , Mutação , Transporte Proteico , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
3.
Genes Dev ; 33(5-6): 288-293, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30804227

RESUMO

The yeast Sfp1 protein regulates both cell division and growth but how it coordinates these processes is poorly understood. We demonstrate that Sfp1 directly controls genes required for ribosome production and many other growth-promoting processes. Remarkably, the complete set of Sfp1 target genes is revealed only by a combination of ChIP (chromatin immunoprecipitation) and ChEC (chromatin endogenous cleavage) methods, which uncover two promoter binding modes, one requiring a cofactor and the other a DNA-recognition motif. Glucose-regulated Sfp1 binding at cell cycle "START" genes suggests that Sfp1 controls cell size by coordinating expression of genes implicated in mass accumulation and cell division.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Regulação Fúngica da Expressão Gênica/genética , Redes Reguladoras de Genes/genética , Regiões Promotoras Genéticas/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/genética , Imunoprecipitação da Cromatina , Proteínas de Ligação a DNA/genética , Glucose/metabolismo , Ligação Proteica , RNA Polimerase II/metabolismo , Regulon/genética , Proteínas de Saccharomyces cerevisiae/genética
4.
Mol Cell ; 71(1): 89-102.e5, 2018 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-29979971

RESUMO

Accessible chromatin is important for RNA polymerase II recruitment and transcription initiation at eukaryotic promoters. We investigated the mechanistic links between promoter DNA sequence, nucleosome positioning, and transcription. Our results indicate that positioning of the transcription start site-associated +1 nucleosome in yeast is critical for efficient TBP binding and is driven by two key factors, the essential chromatin remodeler RSC and a small set of ubiquitous general regulatory factors (GRFs). Our findings indicate that the strength and directionality of RSC action on promoter nucleosomes depends on the arrangement and proximity of two specific DNA motifs. This, together with the effect on nucleosome position observed in double depletion experiments, suggests that, despite their widespread co-localization, RSC and GRFs predominantly act through independent signals to generate accessible chromatin. Our results provide mechanistic insight into how the promoter DNA sequence instructs trans-acting factors to control nucleosome architecture and stimulate transcription initiation.


Assuntos
Montagem e Desmontagem da Cromatina , Nucleossomos/metabolismo , RNA Polimerase II/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Transcrição Gênica , Nucleossomos/genética , RNA Polimerase II/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética
5.
Mol Cell ; 65(3): 578-580, 2017 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-28157510

RESUMO

In this issue of Molecular Cell, Chereji et al. (2017) present new data on MNase-sensitive particles previously identified upstream of transcription start sites at many promoters in budding yeast, and they argue, based upon negative histone-ChIP results, that they are non-nucleosomal signals generated by transcription factors (TFs). We show instead, based upon functional experiments where the relevant TFs are rapidly depleted, that this explanation does not hold, and we argue instead that histone ChIP and chemical cleavage assays have a limited capacity to capture these highly dynamic, MNase-sensitive "fragile" nucleosomes.


Assuntos
Histonas/genética , Nucleossomos , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Sítio de Iniciação de Transcrição
6.
Nucleic Acids Res ; 51(2): 744-764, 2023 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-36610750

RESUMO

Ribosomes are ribozymes, hence correct folding of the rRNAs during ribosome biogenesis is crucial to ensure catalytic activity. RNA helicases, which can modulate RNA-RNA and RNA/protein interactions, are proposed to participate in rRNA tridimensional folding. Here, we analyze the biochemical properties of Dbp6, a DEAD-box RNA helicase required for the conversion of the initial 90S pre-ribosomal particle into the first pre-60S particle. We demonstrate that in vitro, Dbp6 shows ATPase as well as annealing and clamping activities negatively regulated by ATP. Mutations in Dbp6 core motifs involved in ATP binding and ATP hydrolysis are lethal and impair Dbp6 ATPase activity but increase its RNA binding and RNA annealing activities. These data suggest that correct regulation of these activities is important for Dbp6 function in vivo. Using in vivo cross-linking (CRAC) experiments, we show that Dbp6 interacts with 25S rRNA sequences located in the 5' domain I and in the peptidyl transferase center (PTC), and also crosslinks to snoRNAs hybridizing to the immature PTC. We propose that the ATPase and RNA clamping/annealing activities of Dbp6 modulate interactions of snoRNAs with the immature PTC and/or contribute directly to the folding of this region.


Assuntos
RNA Helicases DEAD-box , Ribossomos , Proteínas de Saccharomyces cerevisiae , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , Peptidil Transferases/genética , Peptidil Transferases/metabolismo , Ribossomos/genética , Ribossomos/metabolismo , RNA Helicases/genética , RNA Ribossômico/metabolismo , RNA Nucleolar Pequeno/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
7.
BMC Med ; 22(1): 39, 2024 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-38287349

RESUMO

BACKGROUND: Nutritional intervention preconception and throughout pregnancy has been proposed as an approach to promoting healthy postnatal weight gain in the offspring but few randomised trials have examined this. METHODS: Measurements of weight and length were obtained at multiple time points from birth to 2 years among 576 offspring of women randomised to receive preconception and antenatally either a supplement containing myo-inositol, probiotics, and additional micronutrients (intervention) or a standard micronutrient supplement (control). We examined the influence on age- and sex-standardised BMI at 2 years (WHO standards, adjusting for study site, sex, maternal parity, smoking and pre-pregnancy BMI, and gestational age), together with the change in weight, length, BMI from birth, and weight gain trajectories using latent class growth analysis. RESULTS: At 2 years, there was a trend towards lower mean BMI among intervention offspring (adjusted mean difference [aMD] - 0.14 SD [95% CI 0.30, 0.02], p = 0.09), and fewer had a BMI > 95th percentile (i.e. > 1.65 SD, 9.2% vs 18.0%, adjusted risk ratio [aRR] 0.51 [95% CI 0.31, 0.82], p = 0.006). Longitudinal data revealed that intervention offspring had a 24% reduced risk of experiencing rapid weight gain > 0.67 SD in the first year of life (21.9% vs 31.1%, aRR 0.76 [95% CI 0.58, 1.00], p = 0.047). The risk was likewise decreased for sustained weight gain > 1.34 SD in the first 2 years of life (7.7% vs 17.1%, aRR 0.55 [95% CI 0.34, 0.88], p = 0.014). From five weight gain trajectories identified, there were more intervention offspring in the "normal" weight gain trajectory characterised by stable weight SDS around 0 SD from birth to 2 years (38.8% vs 30.1%, RR 1.29 [95% CI 1.03, 1.62], p = 0.029). CONCLUSIONS: Supplementation with myo-inositol, probiotics, and additional micronutrients preconception and in pregnancy reduced the incidence of rapid weight gain and obesity at 2 years among offspring. Previous reports suggest these effects will likely translate to health benefits, but longer-term follow-up is needed to evaluate this. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02509988 (Universal Trial Number U1111-1171-8056). Registered on 16 July 2015.


Assuntos
Trajetória do Peso do Corpo , Probióticos , Feminino , Humanos , Gravidez , Índice de Massa Corporal , Suplementos Nutricionais , Inositol , Micronutrientes , Aumento de Peso
8.
Mol Cell ; 64(4): 720-733, 2016 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-27818142

RESUMO

Cell growth potential is determined by the rate of ribosome biogenesis, a complex process that requires massive and coordinated transcriptional output. In the yeast Saccharomyces cerevisiae, ribosome biogenesis is highly regulated at the transcriptional level. Although evidence for a system that coordinates ribosomal RNA (rRNA) and ribosomal protein gene (RPG) transcription has been described, the molecular mechanisms remain poorly understood. Here we show that an interaction between the RPG transcriptional activator Ifh1 and the rRNA processing factor Utp22 serves to coordinate RPG transcription with that of rRNA. We demonstrate that Ifh1 is rapidly released from RPG promoters by a Utp22-independent mechanism following growth inhibition, but that its long-term dissociation requires Utp22. We present evidence that RNA polymerase I activity inhibits the ability of Utp22 to titrate Ifh1 from RPG promoters and propose that a dynamic Ifh1-Utp22 interaction fine-tunes RPG expression to coordinate RPG and rRNA transcription.


Assuntos
Regulação Fúngica da Expressão Gênica , RNA Ribossômico/genética , Proteínas Ribossômicas/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Transativadores/genética , Biogênese de Organelas , Regiões Promotoras Genéticas , Ligação Proteica , RNA Polimerase I/genética , RNA Polimerase I/metabolismo , RNA Ribossômico/biossíntese , Proteínas Ribossômicas/biossíntese , Proteínas Ribossômicas/metabolismo , Ribossomos/genética , Ribossomos/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Transativadores/metabolismo , Transcrição Gênica
9.
PLoS Med ; 20(12): e1004260, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38051700

RESUMO

BACKGROUND: Maternal vitamin status preconception and during pregnancy has important consequences for pregnancy outcome and offspring development. Changes in vitamin status from preconception through early and late pregnancy and postpartum have been inferred from cross-sectional data, but longitudinal data on vitamin status from preconception throughout pregnancy and postdelivery are sparse. As such, the influence of vitamin supplementation on vitamin status during pregnancy remains uncertain. This study presents one prespecified outcome from the randomized controlled NiPPeR trial, aiming to identify longitudinal patterns of maternal vitamin status from preconception, through early and late pregnancy, to 6 months postdelivery, and determine the influence of vitamin supplementation. METHODS AND FINDINGS: In the NiPPeR trial, 1,729 women (from the United Kingdom, Singapore, and New Zealand) aged 18 to 38 years and planning conception were randomized to receive a standard vitamin supplement (control; n = 859) or an enhanced vitamin supplement (intervention; n = 870) starting in preconception and continued throughout pregnancy, with blinding of participants and research staff. Supplement components common to both treatment groups included folic acid, ß-carotene, iron, calcium, and iodine; components additionally included in the intervention group were riboflavin, vitamins B6, B12, and D (in amounts available in over-the-counter supplements), myo-inositol, probiotics, and zinc. The primary outcome of the study was glucose tolerance at 28 weeks' gestation, measured by oral glucose tolerance test. The secondary outcome reported in this study was the reduction in maternal micronutrient insufficiency in riboflavin, vitamin B6, vitamin B12, and vitamin D, before and during pregnancy. We measured maternal plasma concentrations of B-vitamins, vitamin D, and markers of insufficiency/deficiency (homocysteine, hydroxykynurenine-ratio, methylmalonic acid) at recruitment, 1 month after commencing intervention preconception, in early pregnancy (7 to 11 weeks' gestation) and late pregnancy (around 28 weeks' gestation), and postdelivery (6 months after supplement discontinuation). We derived standard deviation scores (SDS) to characterize longitudinal changes among participants in the control group and measured differences between the 2 groups. At recruitment, the proportion of patients with marginal or low plasma status was 29.2% for folate (<13.6 nmol/L), 7.5% and 82.0% for riboflavin (<5 nmol/L and ≤26.5 nmol/L, respectively), 9.1% for vitamin B12 (<221 pmol/L), and 48.7% for vitamin D (<50 nmol/L); these proportions were balanced between the groups. Over 90% of all participants had low or marginal status for one or more of these vitamins at recruitment. Among participants in the control group, plasma concentrations of riboflavin declined through early and late pregnancy, whereas concentrations of 25-hydroxyvitamin D were unchanged in early pregnancy, and concentrations of vitamin B6 and B12 declined throughout pregnancy, becoming >1 SDS lower than baseline by 28 weeks gestation. In the control group, 54.2% of participants developed low late-pregnancy vitamin B6 concentrations (pyridoxal 5-phosphate <20 nmol/L). After 1 month of supplementation, plasma concentrations of supplement components were substantially higher among participants in the intervention group than those in the control group: riboflavin by 0.77 SDS (95% CI 0.68 to 0.87, p < 0.0001), vitamin B6 by 1.07 SDS (0.99 to 1.14, p < 0.0001), vitamin B12 by 0.55 SDS (0.46 to 0.64, p < 0.0001), and vitamin D by 0.51 SDS (0.43 to 0.60, p < 0.0001), with higher levels in the intervention group maintained during pregnancy. Markers of vitamin insufficiency/deficiency were reduced in the intervention group, and the proportion of participants with vitamin D insufficiency (<50 nmol/L) during late pregnancy was lower in the intervention group (35.1% versus 8.5%; p < 0.0001). Plasma vitamin B12 remained higher in the intervention group than in the control group 6 months postdelivery (by 0.30 SDS (0.14, 0.46), p = 0.0003). The main limitation is that generalizability to the global population is limited by the high-resource settings and the lack of African and Amerindian women in particular. CONCLUSIONS: Over 90% of the trial participants had marginal or low concentrations of one or more of folate, riboflavin, vitamin B12, or vitamin D during preconception, and many developed markers of vitamin B6 deficiency in late pregnancy. Preconception/pregnancy supplementation in amounts available in over-the-counter supplements substantially reduces the prevalence of vitamin deficiency and depletion markers before and during pregnancy, with higher maternal plasma vitamin B12 maintained during the recommended lactational period. TRIAL REGISTRATION: ClinicalTrials.gov NCT02509988; U1111-1171-8056.


Assuntos
Ácido Fólico , Complexo Vitamínico B , Feminino , Humanos , Gravidez , Estudos Transversais , Suplementos Nutricionais , Resultado da Gravidez , Riboflavina , Vitamina B 12 , Vitamina B 6 , Vitamina D , Adolescente , Adulto Jovem , Adulto
10.
Am J Physiol Regul Integr Comp Physiol ; 323(2): R244-R254, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35726870

RESUMO

Fish oil (FO) supplements are consumed during pregnancy to increase dietary omega-3. However, FO is often oxidized past recommended limits. In rats, a large dose of highly oxidized FO substantially increased newborn mortality, but the effects of human-relevant doses of less oxidized oil are unknown. A dose-response study in rats was conducted to estimate the safe level of oxidation during pregnancy. Sprague-Dawley rat dams were mated, then individually housed and provided with a gel treatment on each day of pregnancy. Treatment groups differed only in the FO content of the gel; control (no oil), PV5, PV10, and PV40 [0.05 mL of FO oxidized to a peroxide value (PV) of 5, 10, or 40 meq/kg], or PV40(1 mL) (1 mL of PV40). A subset of dams was culled on gestational day 20 to enable sampling, and the remainder were allowed to give birth. Newborn mortality was recorded. Offspring were sampled on postnatal days 2 and 21, and dams on day 21. There were no signs of unwellness during pregnancy. However, there was markedly increased neonatal mortality affecting the PV40(1 mL) (12.8%) and PV40 (6.3%) groups, but not the control, PV5, or PV10 groups (1%-1.4%). Dietary-oxidized FO altered the expression of placental genes involved in antioxidant pathways and the production of free radicals. Highly oxidized FO was toxic in rat pregnancy leading to a marked increase in mortality even at a human-relevant dose. We observed no toxic effects of FOs with PV ≤10 meq/kg, suggesting that this is an appropriate maximum limit.


Assuntos
Óleos de Peixe , Placenta , Animais , Dieta , Suplementos Nutricionais , Feminino , Óleos de Peixe/toxicidade , Humanos , Gravidez , Ratos , Ratos Sprague-Dawley
11.
Nucleic Acids Res ; 48(20): 11408-11420, 2020 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-33084907

RESUMO

While expression of ribosomal protein genes (RPGs) in the budding yeast has been extensively studied, a longstanding enigma persists regarding their co-regulation under fluctuating growth conditions. Most RPG promoters display one of two distinct arrangements of a core set of transcription factors (TFs) and are further differentiated by the presence or absence of the HMGB protein Hmo1. However, a third group of promoters appears not to be bound by any of these proteins, raising the question of how the whole suite of genes is co-regulated. We demonstrate here that all RPGs are regulated by two distinct, but complementary mechanisms driven by the TFs Ifh1 and Sfp1, both of which are required for maximal expression in optimal conditions and coordinated downregulation upon stress. At the majority of RPG promoters, Ifh1-dependent regulation predominates, whereas Sfp1 plays the major role at all other genes. We also uncovered an unexpected protein homeostasis-dependent binding property of Hmo1 at RPG promoters. Finally, we show that the Ifh1 paralog Crf1, previously described as a transcriptional repressor, can act as a constitutive RPG activator. Our study provides a more complete picture of RPG regulation and may serve as a paradigm for unravelling RPG regulation in multicellular eukaryotes.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Regulação Fúngica da Expressão Gênica , Proteínas de Grupo de Alta Mobilidade/metabolismo , Proteínas Ribossômicas/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Estresse Fisiológico/genética , Transativadores/metabolismo , Transcrição Gênica , Sequenciamento de Cromatina por Imunoprecipitação , Proteínas de Ligação a DNA/genética , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Proteínas de Grupo de Alta Mobilidade/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/antagonistas & inibidores , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Regiões Promotoras Genéticas , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Proteínas Ribossômicas/biossíntese , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Sirolimo/farmacologia , Estresse Fisiológico/efeitos dos fármacos , Transativadores/genética
12.
Emerg Radiol ; 29(6): 995-1002, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35971025

RESUMO

PURPOSE: We employ nnU-Net, a state-of-the-art self-configuring deep learning-based semantic segmentation method for quantitative visualization of hemothorax (HTX) in trauma patients, and assess performance using a combination of overlap and volume-based metrics. The accuracy of hemothorax volumes for predicting a composite of hemorrhage-related outcomes - massive transfusion (MT) and in-hospital mortality (IHM) not related to traumatic brain injury - is assessed and compared to subjective expert consensus grading by an experienced chest and emergency radiologist. MATERIALS AND METHODS: The study included manually labeled admission chest CTs from 77 consecutive adult patients with non-negligible (≥ 50 mL) traumatic HTX between 2016 and 2018 from one trauma center. DL results of ensembled nnU-Net were determined from fivefold cross-validation and compared to individual 2D, 3D, and cascaded 3D nnU-Net results using the Dice similarity coefficient (DSC) and volume similarity index. Pearson's r, intraclass correlation coefficient (ICC), and mean bias were also determined for the best performing model. Manual and automated hemothorax volumes and subjective hemothorax volume grades were analyzed as predictors of MT and IHM using AUC comparison. Volume cut-offs yielding sensitivity or specificity ≥ 90% were determined from ROC analysis. RESULTS: Ensembled nnU-Net achieved a mean DSC of 0.75 (SD: ± 0.12), and mean volume similarity of 0.91 (SD: ± 0.10), Pearson r of 0.93, and ICC of 0.92. Mean overmeasurement bias was only 1.7 mL despite a range of manual HTX volumes from 35 to 1503 mL (median: 178 mL). AUC of automated volumes for the composite outcome was 0.74 (95%CI: 0.58-0.91), compared to 0.76 (95%CI: 0.58-0.93) for manual volumes, and 0.76 (95%CI: 0.62-0.90) for consensus expert grading (p = 0.93). Automated volume cut-offs of 77 mL and 334 mL predicted the outcome with 93% sensitivity and 90% specificity respectively. CONCLUSION: Automated HTX volumetry had high method validity, yielded interpretable visual results, and had similar performance for the hemorrhage-related outcomes assessed compared to manual volumes and expert consensus grading. The results suggest promising avenues for automated HTX volumetry in research and clinical care.


Assuntos
Aprendizado Profundo , Traumatismos Torácicos , Adulto , Humanos , Hemotórax/diagnóstico por imagem , Projetos Piloto , Traumatismos Torácicos/complicações , Traumatismos Torácicos/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos
13.
Biochem Soc Trans ; 49(4): 1589-1599, 2021 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-34240738

RESUMO

Ribosome biogenesis requires prodigious transcriptional output in rapidly growing yeast cells and is highly regulated in response to both growth and stress signals. This minireview focuses on recent developments in our understanding of this regulatory process, with an emphasis on the 138 ribosomal protein genes (RPGs) themselves and a group of >200 ribosome biogenesis (RiBi) genes whose products contribute to assembly but are not part of the ribosome. Expression of most RPGs depends upon Rap1, a pioneer transcription factor (TF) required for the binding of a pair of RPG-specific TFs called Fhl1 and Ifh1. RPG expression is correlated with Ifh1 promoter binding, whereas Rap1 and Fhl1 remain promoter-associated upon stress-induced down regulation. A TF called Sfp1 has also been implicated in RPG regulation, though recent work reveals that its primary function is in activation of RiBi and other growth-related genes. Sfp1 plays an important regulatory role at a small number of RPGs where Rap1-Fhl1-Ifh1 action is subsidiary or non-existent. In addition, nearly half of all RPGs are bound by Hmo1, which either stabilizes or re-configures Fhl1-Ifh1 binding. Recent studies identified the proline rotamase Fpr1, known primarily for its role in rapamycin-mediated inhibition of the TORC1 kinase, as an additional TF at RPG promoters. Fpr1 also affects Fhl1-Ifh1 binding, either independently or in cooperation with Hmo1. Finally, a major recent development was the discovery of a protein homeostasis mechanism driven by unassembled ribosomal proteins, referred to as the Ribosome Assembly Stress Response (RASTR), that controls RPG transcription through the reversible condensation of Ifh1.


Assuntos
Estresse Oxidativo , Ribossomos/metabolismo , Saccharomyces cerevisiae/metabolismo , Transdução de Sinais , Transcrição Gênica , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
14.
Anal Biochem ; 592: 113558, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-31911045

RESUMO

Amino acids (AAs) and one-carbon (1-C) metabolism compounds are involved in a range of key metabolic pathways, and mediate numerous health and disease processes in the human body. Previous assays have quantified a limited selection of these compounds and typically require extensive manual handling. Here, we describe the robotic automation of an analytical method for the simultaneous quantification of 37 1-C metabolites, amino acids, and precursors using reversed-phase ultra-high-pressure liquid chromatography coupled with tandem mass spectrometry (UHPLC/MS-MS). Compound extraction from human plasma was tested manually before being robotically automated. The final automated analytical panel was validated on human plasma samples. Our automated and multiplexed method holds promise for application to large cohort studies.


Assuntos
Aminoácidos/sangue , Automação Laboratorial/instrumentação , Cromatografia Líquida de Alta Pressão/instrumentação , Robótica , Espectrometria de Massas em Tandem/instrumentação , Humanos
15.
Pediatr Diabetes ; 20(7): 892-900, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31237756

RESUMO

BACKGROUND: Partial remission (PREM) by the insulin dose-adjusted HbA1c (IDAA1c) method has not been evaluated for the combined associations of ethnicity and socioeconomic status in children and adolescents with type 1 diabetes (T1D). OBJECTIVE: To investigate prevalence and predictors of PREM defined by IDAA1c. METHODS: Six hundred fourteen of 678 children (aged <15 years) with new-onset T1D (2000-2013) from a regional pediatric diabetes service (Auckland, New Zealand). RESULTS: Overall rate of PREM at 3 months was 42.4%, and lower in Maori/Pacific children (28.6%; P = .006) and those of other ethnicities (28.8%; P = .030) compared with New Zealand Europeans (50.4%). Comparing the most and least deprived socioeconomic quintiles, the odds of PREM were lower among the most deprived (adjusted odds ratio [aOR] 0.44; P = .019). Lower rates of PREM were seen in children aged 0 to 4.9 years (23.8%) and 10 to 14 years (40.9%) than in children aged 5 to 9.9 years (57.4%; P < .05). Further predictors of lower rates of PREM were ketoacidosis at diagnosis (aOR 0.54 with DKA; P = .002) and diabetes duration (aOR 0.84 per month; P < .0001). Patient's sex, body mass index standard deviation score, or autoantibodies were not associated with PREM. PREM at 3 months was associated with lower HbA1c over 18 months compared with children not in PREM (65.0 vs 71.3 mmol/mol; P < .0001), independent of ketoacidosis. CONCLUSIONS: This study on a regional cohort of youth with T1D showed social and ethnic disparities in rates of PREM defined by IDAA1c. Further research into reducing ketoacidosis rates at diagnosis and addressing factors associated with lower rates of PREM in non-European children are important health priorities.


Assuntos
Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 1/epidemiologia , Hemoglobinas Glicadas/metabolismo , Insulina/administração & dosagem , Adolescente , Criança , Pré-Escolar , Estudos de Coortes , Cetoacidose Diabética/epidemiologia , Relação Dose-Resposta a Droga , Feminino , Hemoglobinas Glicadas/análise , Hospitais Especializados , Humanos , Lactente , Recém-Nascido , Masculino , Nova Zelândia , Medicina de Precisão/métodos , Programas Médicos Regionais , Indução de Remissão , Estudos Retrospectivos , Fatores Socioeconômicos
16.
PLoS Genet ; 12(11): e1006414, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27820830

RESUMO

The Rif1 protein is a negative regulator of DNA replication initiation in eukaryotes. Here we show that budding yeast Rif1 inhibits DNA replication initiation at the rDNA locus. Absence of Rif1, or disruption of its interaction with PP1/Glc7 phosphatase, leads to more intensive rDNA replication. The effect of Rif1-Glc7 on rDNA replication is similar to that of the Sir2 deacetylase, and the two would appear to act in the same pathway, since the rif1Δ sir2Δ double mutant shows no further increase in rDNA replication. Loss of Rif1-Glc7 activity is also accompanied by an increase in rDNA repeat instability that again is not additive with the effect of sir2Δ. We find, in addition, that the viability of rif1Δ cells is severely compromised in combination with disruption of the MRX or Ctf4-Mms22 complexes, both of which are implicated in stabilization of stalled replication forks. Significantly, we show that removal of the rDNA replication fork barrier (RFB) protein Fob1, alleviation of replisome pausing by deletion of the Tof1/Csm3 complex, or a large deletion of the rDNA repeat array all rescue this synthetic growth defect of rif1Δ cells lacking in addition either MRX or Ctf4-Mms22 activity. These data suggest that the repression of origin activation by Rif1-Glc7 is important to avoid the deleterious accumulation of stalled replication forks at the rDNA RFB, which become lethal when fork stability is compromised. Finally, we show that Rif1-Glc7, unlike Sir2, has an important effect on origin firing outside of the rDNA locus that serves to prevent activation of the DNA replication checkpoint. Our results thus provide insights into a mechanism of replication control within a large repetitive chromosomal domain and its importance for the maintenance of genome stability. These findings may have important implications for metazoans, where large blocks of repetitive sequences are much more common.


Assuntos
Replicação do DNA/genética , DNA Ribossômico/genética , Proteína Fosfatase 1/genética , Proteínas Repressoras/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Ligação a Telômeros/genética , Proteínas de Ligação a DNA/genética , Instabilidade Genômica , Origem de Replicação/genética , Saccharomyces cerevisiae , Proteínas Reguladoras de Informação Silenciosa de Saccharomyces cerevisiae/genética , Sirtuína 2/genética , Telômero/genética
18.
Pediatr Endocrinol Rev ; 16(Suppl 1): 113-122, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30378789

RESUMO

ISS is the commonest cause of short stature and poor growth and is arbitrarily defined as a height < -2 SDS without an identified cause. ISS consists largely of normal children with the remainder unrecognised conditions, mainly syndromes and genetic (monogenic and polygenic) causes. Growth response to rhGH is widely variable reflecting the heterogeneity of ISS. Further identification of genetic causes of ISS will better characterise treatment response. rhGH during childhood has been shown in RCTs to improve adult height by approximately 4 cm which is less than seen in other treated growth disorders. Factors that influence response include; younger age, longer birth length, lower height compared to mid-parental height, delayed bone age and larger rhGH dose. The evidence that short stature is associated with psychological well-being and quality of life is minimal and that rhGH could improve this is scant. Further research in this area is urgently required.


Assuntos
Nanismo , Hormônio do Crescimento/uso terapêutico , Estatura , Nanismo/tratamento farmacológico , Transtornos do Crescimento , Humanos , Qualidade de Vida
19.
Pediatr Diabetes ; 18(7): 553-558, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27726271

RESUMO

BACKGROUND: There has been little change in the incidence of diabetic ketoacidosis (DKA) in newly diagnosed type 1 diabetes mellitus (T1DM) in children and adolescents in most developed countries. OBJECTIVES: To assess potentially modifiable antecedents of DKA in children <15 years of age with new onset T1DM. METHODS: Retrospective review of prospectively collected data from a complete regional cohort of children with T1DM in Auckland (New Zealand) from 2010 to 2014. DKA and severity were defined according to the ISPAD 2014 guidelines. RESULTS: A total of 263 children presented with new onset T1DM during the 5-year study period at 9.0 years of age (range 1.0-14.7), of whom 61% were NZ-European, 14% Maori, 13% Pacifica, and 11% other. A total of 71 patients (27%) were in DKA, including 31 mild, 20 moderate, and 20 severe DKA. DKA was associated with no family history of T1DM, higher glycated hemoglobin (HbA1c) values at presentation, self-presenting to secondary care, health care professional contacts in the 4 weeks before final presentation, and greater deprivation. Although a delay in referral from primary care for laboratory testing was common (81/216), only delay for more than 48 hours was associated with increased risk of DKA (11/22 > 48 h vs 12/59 referred at <48 h, P = .013). CONCLUSIONS: These data suggest that in addition to lack of family awareness potentially modifiable risk factors for new onset DKA include prolonged delay for laboratory testing and a low index of medical suspicion for T1DM leading to delayed diagnosis.


Assuntos
Diabetes Mellitus Tipo 1/diagnóstico , Cetoacidose Diabética/prevenção & controle , Adolescente , Glicemia/análise , Criança , Pré-Escolar , Estudos de Coortes , Terapia Combinada , Diagnóstico Tardio , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/terapia , Diabetes Mellitus Tipo 1/urina , Cetoacidose Diabética/epidemiologia , Família , Feminino , Glicosúria/epidemiologia , Glicosúria/prevenção & controle , Conhecimentos, Atitudes e Prática em Saúde , Hospitais Pediátricos , Humanos , Masculino , Auditoria Médica , Nova Zelândia/epidemiologia , Encaminhamento e Consulta , Programas Médicos Regionais , Estudos Retrospectivos , Risco
20.
J Paediatr Child Health ; 53(12): 1208-1214, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28727196

RESUMO

AIM: There is no consensus on the optimal insulin treatment for children newly diagnosed with type 1 diabetes mellitus (T1DM). The aims of this study were (i) to describe the insulin regimens used at diagnosis by patient age and geographical region and (ii) to explore differences between and within Australia (AU) and New Zealand (NZ) with regards to other aspects of patient management and education. METHODS: An online survey of medical professionals caring for children with T1DM in AU and NZ was undertaken. Questions included clinic demographics, insulin regimen/dosing choices and patient education. RESULTS: Of 110 clinicians identified, 100 responded (91%). The majority of those in AU (69%, P < 0.0001) favour multiple daily injections (MDI) for all ages. In NZ, for patients < 10 years old, (twice daily (BD)) BD therapy was favoured (75%, P < 0.0001), with MDI dominant for ages ≥ 10 years (82%, P < 0.0001). Insulin pump therapy was never considered at diagnosis in NZ, but 38% of clinicians in AU considered using pumps at diagnosis in patients <2 years, but rarely in patients aged 2 and over (16%). Differences in clinician choices were also seen in relation to starting insulin dose. CONCLUSION: This is the first study to examine current clinical practice with regards to children newly diagnosed with T1DM. Practice varies across Australasia by clinician and region. This lack of consensus is likely driven by ongoing debates in the current paediatric diabetes evidence base as well as by differences in clinician/centre preference, variations in resourcing and their interpretations of the influence of various patient factors.


Assuntos
Diabetes Mellitus Tipo 1/tratamento farmacológico , Insulina/administração & dosagem , Padrões de Prática Médica/estatística & dados numéricos , Adulto , Idoso , Austrália , Criança , Pré-Escolar , Sistemas de Liberação de Medicamentos/estatística & dados numéricos , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Nova Zelândia , Inquéritos e Questionários , Adulto Jovem
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