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1.
RNA ; 26(4): 419-438, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31915290

RESUMO

The translation preinitiation complex (PIC) scans the mRNA for an AUG codon in a favorable context. Previous findings suggest that the factor eIF1 discriminates against non-AUG start codons by impeding full accommodation of Met-tRNAi in the P site of the 40S ribosomal subunit, necessitating eIF1 dissociation for start codon selection. Consistent with this, yeast eIF1 substitutions that weaken its binding to the PIC increase initiation at UUG codons on a mutant his4 mRNA and particular synthetic mRNA reporters; and also at the AUG start codon of the mRNA for eIF1 itself owing to its poor Kozak context. It was not known however whether such eIF1 mutants increase initiation at suboptimal start codons genome-wide. By ribosome profiling, we show that the eIF1-L96P variant confers increased translation of numerous upstream open reading frames (uORFs) initiating with either near-cognate codons (NCCs) or AUGs in poor context. The increased uORF translation is frequently associated with the reduced translation of the downstream main coding sequences (CDS). Initiation is also elevated at certain NCCs initiating amino-terminal extensions, including those that direct mitochondrial localization of the GRS1 and ALA1 products, and at a small set of main CDS AUG codons with especially poor context, including that of eIF1 itself. Thus, eIF1 acts throughout the yeast translatome to discriminate against NCC start codons and AUGs in poor context; and impairing this function enhances the repressive effects of uORFs on CDS translation and alters the ratios of protein isoforms translated from near-cognate versus AUG start codons.


Assuntos
Códon de Iniciação , Fator de Iniciação 1 em Eucariotos/metabolismo , Fases de Leitura Aberta , Iniciação Traducional da Cadeia Peptídica , Oxirredutases do Álcool/genética , Oxirredutases do Álcool/metabolismo , Aminoidrolases/genética , Aminoidrolases/metabolismo , Regulação Fúngica da Expressão Gênica , Genoma Fúngico , Glicina-tRNA Ligase/genética , Glicina-tRNA Ligase/metabolismo , Pirofosfatases/genética , Pirofosfatases/metabolismo , RNA Mensageiro/química , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ribossomos/metabolismo , Saccharomyces cerevisiae , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
2.
Hum Mutat ; 41(11): 1918-1930, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32790018

RESUMO

Diamond-Blackfan anemia (DBA) is a ribosomopathy of variable expressivity and penetrance characterized by red cell aplasia, congenital anomalies, and predisposition to certain cancers, including early-onset colorectal cancer (CRC). DBA is primarily caused by a dominant mutation of a ribosomal protein (RP) gene, although approximately 20% of patients remain genetically uncharacterized despite exome sequencing and copy number analysis. Although somatic loss-of-function mutations in RP genes have been reported in sporadic cancers, with the exceptions of 5q-myelodysplastic syndrome (RPS14) and microsatellite unstable CRC (RPL22), these cancers are not enriched in DBA. Conversely, pathogenic variants in RPS20 were previously implicated in familial CRC; however, none of the reported individuals had classical DBA features. We describe two unrelated children with DBA lacking variants in known DBA genes who were found by exome sequencing to have de novo novel missense variants in RPS20. The variants affect the same amino acid but result in different substitutions and reduce the RPS20 protein level. Yeast models with mutation of the cognate residue resulted in defects in growth, ribosome biogenesis, and polysome formation. These findings expand the phenotypic spectrum of RPS20 mutation beyond familial CRC to include DBA, which itself is associated with increased risk of CRC.


Assuntos
Anemia de Diamond-Blackfan/genética , Mutação em Linhagem Germinativa , Proteínas Ribossômicas/genética , Adolescente , Sequência de Aminoácidos , Criança , Neoplasias Colorretais/genética , Feminino , Humanos , Recém-Nascido , Masculino , Linhagem , Penetrância , Estrutura Terciária de Proteína , Sequenciamento do Exoma
3.
BMC Biol ; 17(1): 101, 2019 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-31810458

RESUMO

BACKGROUND: Translation of an mRNA in eukaryotes starts at an AUG codon in most cases, but near-cognate codons (NCCs) such as UUG, ACG, and AUU can also be used as start sites at low levels in Saccharomyces cerevisiae. Initiation from NCCs or AUGs in the 5'-untranslated regions (UTRs) of mRNAs can lead to translation of upstream open reading frames (uORFs) that might regulate expression of the main ORF (mORF). Although there is some circumstantial evidence that the translation of uORFs can be affected by environmental conditions, little is known about how it is affected by changes in growth temperature. RESULTS: Using reporter assays, we found that changes in growth temperature can affect translation from NCC start sites in yeast cells, suggesting the possibility that gene expression could be regulated by temperature by altering use of different uORF start codons. Using ribosome profiling, we provide evidence that growth temperature regulates the efficiency of translation of nearly 200 uORFs in S. cerevisiae. Of these uORFs, most that start with an AUG codon have increased translational efficiency at 37 °C relative to 30 °C and decreased efficiency at 20 °C. For translationally regulated uORFs starting with NCCs, we did not observe a general trend for the direction of regulation as a function of temperature, suggesting mRNA-specific features can determine the mode of temperature-dependent regulation. Consistent with this conclusion, the position of the uORFs in the 5'-leader relative to the 5'-cap and the start codon of the main ORF correlates with the direction of temperature-dependent regulation of uORF translation. We have identified several novel cases in which changes in uORF translation are inversely correlated with changes in the translational efficiency of the downstream main ORF. Our data suggest that translation of these mRNAs is subject to temperature-dependent, uORF-mediated regulation. CONCLUSIONS: Our data suggest that alterations in the translation of specific uORFs by temperature can regulate gene expression in S. cerevisiae.


Assuntos
Códon de Iniciação/metabolismo , Fases de Leitura Aberta/genética , RNA Fúngico/metabolismo , Saccharomyces cerevisiae/genética , Regiões 5' não Traduzidas , Temperatura
4.
Proc Natl Acad Sci U S A ; 113(38): 10464-72, 2016 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-27601676

RESUMO

DEAD-box RNA helicases eukaryotic translation initiation factor 4A (eIF4A) and Ded1 promote translation by resolving mRNA secondary structures that impede preinitiation complex (PIC) attachment to mRNA or scanning. Eukaryotic translation initiation factor 4B (eIF4B) is a cofactor for eIF4A but also might function independently of eIF4A. Ribosome profiling of mutants lacking eIF4B or with impaired eIF4A or Ded1 activity revealed that eliminating eIF4B reduces the relative translational efficiencies of many more genes than does inactivation of eIF4A, despite comparable reductions in bulk translation, and few genes display unusually strong requirements for both factors. However, either eliminating eIF4B or inactivating eIF4A preferentially impacts mRNAs with longer, more structured 5' untranslated regions (UTRs). These findings reveal an eIF4A-independent role for eIF4B in addition to its function as eIF4A cofactor in promoting PIC attachment or scanning on structured mRNAs. eIF4B, eIF4A, and Ded1 mutations also preferentially impair translation of longer mRNAs in a fashion mitigated by the ability to form closed-loop messenger ribonucleoprotein particles (mRNPs) via eIF4F-poly(A)-binding protein 1 (Pab1) association, suggesting cooperation between closed-loop assembly and eIF4B/helicase functions. Remarkably, depleting eukaryotic translation initiation factor 4G (eIF4G), the scaffold subunit of eukaryotic translation initiation factor 4F (eIF4F), preferentially impacts short mRNAs with strong closed-loop potential and unstructured 5' UTRs, exactly the opposite features associated with hyperdependence on the eIF4B/helicases. We propose that short, highly efficient mRNAs preferentially depend on the stimulatory effects of eIF4G-dependent closed-loop assembly.


Assuntos
RNA Helicases DEAD-box/genética , Fator de Iniciação Eucariótico 4G/genética , Fatores de Iniciação em Eucariotos/genética , Biossíntese de Proteínas , Regiões 5' não Traduzidas , Fator de Iniciação 4A em Eucariotos/genética , Fator de Iniciação 4F em Eucariotos/genética , Conformação de Ácido Nucleico , Proteínas de Ligação a Poli(A)/genética , RNA Mensageiro/genética , Ribossomos/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética
5.
Genome Res ; 25(8): 1196-205, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26122911

RESUMO

DEAD-box RNA helicases eIF4A and Ded1 are believed to promote translation initiation by resolving mRNA secondary structures that impede ribosome attachment at the mRNA 5' end or subsequent scanning of the 5' UTR, but whether they perform unique or overlapping functions in vivo is poorly understood. We compared the effects of mutations in Ded1 or eIF4A on global translational efficiencies (TEs) in budding yeast Saccharomyces cerevisiae by ribosome footprint profiling. Despite similar reductions in bulk translation, inactivation of a cold-sensitive Ded1 mutant substantially reduced the TEs of >600 mRNAs, whereas inactivation of a temperature-sensitive eIF4A variant encoded by tif1-A79V (in a strain lacking the ortholog TIF2) yielded <40 similarly impaired mRNAs. The broader requirement for Ded1 did not reflect more pervasive secondary structures at low temperature, as inactivation of temperature-sensitive and cold-sensitive ded1 mutants gave highly correlated results. Interestingly, Ded1-dependent mRNAs exhibit greater than average 5' UTR length and propensity for secondary structure, implicating Ded1 in scanning through structured 5' UTRs. Reporter assays confirmed that cap-distal stem-loop insertions increase dependence on Ded1 but not eIF4A for efficient translation. While only a small fraction of mRNAs shows a heightened requirement for eIF4A, dependence on eIF4A is correlated with requirements for Ded1 and 5' UTR features characteristic of Ded1-dependent mRNAs. Our findings suggest that Ded1 is critically required to promote scanning through secondary structures within 5' UTRs, and while eIF4A cooperates with Ded1 in this function, it also promotes a step of initiation common to virtually all yeast mRNAs.


Assuntos
RNA Helicases DEAD-box/metabolismo , Fator de Iniciação 4F em Eucariotos/metabolismo , Biossíntese de Proteínas , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Regiões 5' não Traduzidas , RNA Helicases DEAD-box/genética , Fator de Iniciação 4F em Eucariotos/genética , Genoma Fúngico , Mutação , Conformação de Ácido Nucleico , RNA Helicases , RNA Fúngico/química , RNA Mensageiro/química , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética
6.
J Biol Chem ; 289(3): 1704-22, 2014 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-24285537

RESUMO

eIF4B has been implicated in attachment of the 43 S preinitiation complex (PIC) to mRNAs and scanning to the start codon. We recently determined that the internal seven repeats (of ∼26 amino acids each) of Saccharomyces cerevisiae eIF4B (yeIF4B) compose the region most critically required to enhance mRNA recruitment by 43 S PICs in vitro and stimulate general translation initiation in yeast. Moreover, although the N-terminal domain (NTD) of yeIF4B contributes to these activities, the RNA recognition motif is dispensable. We have now determined that only two of the seven internal repeats are sufficient for wild-type (WT) yeIF4B function in vivo when all other domains are intact. However, three or more repeats are needed in the absence of the NTD or when the functions of eIF4F components are compromised. We corroborated these observations in the reconstituted system by demonstrating that yeIF4B variants with only one or two repeats display substantial activity in promoting mRNA recruitment by the PIC, whereas additional repeats are required at lower levels of eIF4A or when the NTD is missing. These findings indicate functional overlap among the 7-repeats and NTD domains of yeIF4B and eIF4A in mRNA recruitment. Interestingly, only three highly conserved positions in the 26-amino acid repeat are essential for function in vitro and in vivo. Finally, we identified conserved motifs in the NTD and demonstrate functional overlap of two such motifs. These results provide a comprehensive description of the critical sequence elements in yeIF4B that support eIF4F function in mRNA recruitment by the PIC.


Assuntos
Fatores de Iniciação em Eucariotos/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Motivos de Aminoácidos , Fator de Iniciação 4F em Eucariotos/química , Fator de Iniciação 4F em Eucariotos/genética , Fator de Iniciação 4F em Eucariotos/metabolismo , Fatores de Iniciação em Eucariotos/química , Fatores de Iniciação em Eucariotos/genética , Estrutura Terciária de Proteína , RNA Fúngico/química , RNA Fúngico/genética , RNA Fúngico/metabolismo , RNA Mensageiro/química , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Sequências Repetitivas de Aminoácidos , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética
7.
RNA ; 19(2): 191-207, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23236192

RESUMO

Eukaryotic translation initiation factor (eIF)4B stimulates recruitment of mRNA to the 43S ribosomal pre-initiation complex (PIC). Yeast eIF4B (yeIF4B), shown previously to bind single-stranded (ss) RNA, consists of an N-terminal domain (NTD), predicted to be unstructured in solution; an RNA-recognition motif (RRM); an unusual domain comprised of seven imperfect repeats of 26 amino acids; and a C-terminal domain. Although the mechanism of yeIF4B action has remained obscure, most models have suggested central roles for its RRM and ssRNA-binding activity. We have dissected the functions of yeIF4B's domains and show that the RRM and its ssRNA-binding activity are dispensable in vitro and in vivo. Instead, our data indicate that the 7-repeats and NTD are the most critical domains, which mediate binding of yeIF4B to the head of the 40S ribosomal subunit via interaction with Rps20. This interaction induces structural changes in the ribosome's mRNA entry channel that could facilitate mRNA loading. We also show that yeIF4B strongly promotes productive interaction of eIF4A with the 43S•mRNA PIC in a manner required for efficient mRNA recruitment.


Assuntos
Fator de Iniciação 4A em Eucariotos/metabolismo , Fatores de Iniciação em Eucariotos/metabolismo , RNA Mensageiro/metabolismo , Proteínas Ribossômicas/metabolismo , Subunidades Ribossômicas Menores de Eucariotos/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Sequência de Aminoácidos , Substituição de Aminoácidos , Fator de Iniciação 4A em Eucariotos/genética , Fatores de Iniciação em Eucariotos/genética , Modelos Moleculares , Dados de Sequência Molecular , Iniciação Traducional da Cadeia Peptídica , Polirribossomos/química , Polirribossomos/metabolismo , Ligação Proteica , Biossíntese de Proteínas , Estrutura Terciária de Proteína , RNA Fúngico/genética , RNA Fúngico/metabolismo , RNA Mensageiro/genética , RNA Ribossômico 18S/química , RNA Ribossômico 18S/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Subunidades Ribossômicas Menores de Eucariotos/química , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética , Alinhamento de Sequência , Deleção de Sequência
8.
J Biol Chem ; 288(4): 2340-54, 2013 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-23184954

RESUMO

Translation initiation factor eIF4F (eukaryotic initiation factor 4F), composed of eIF4E, eIF4G, and eIF4A, binds to the m(7)G cap structure of mRNA and stimulates recruitment of the 43S preinitiation complex and subsequent scanning to the initiation codon. The HEAT domain of eIF4G stabilizes the active conformation of eIF4A required for its RNA helicase activity. Mammalian eIF4B also stimulates eIF4A activity, but this function appears to be lacking in yeast, making it unclear how yeast eIF4B (yeIF4B/Tif3) stimulates translation. We identified Ts(-) mutations in the HEAT domains of yeast eIF4G1 and eIF4G2 that are suppressed by overexpressing either yeIF4B or eIF4A, whereas others are suppressed only by eIF4A overexpression. Importantly, suppression of HEAT domain substitutions by yeIF4B overexpression was correlated with the restoration of native eIF4A·eIF4G complexes in vivo, and the rescue of specific mutant eIF4A·eIF4G complexes by yeIF4B was reconstituted in vitro. Association of eIF4A with WT eIF4G in vivo also was enhanced by yeIF4B overexpression and was impaired in cells lacking yeIF4B. Furthermore, we detected native complexes containing eIF4G and yeIF4B but lacking eIF4A. These and other findings lead us to propose that yeIF4B acts in vivo to promote eIF4F assembly by enhancing a conformation of the HEAT domain of yeast eIF4G conducive for stable binding to eIF4A.


Assuntos
Fator de Iniciação 4A em Eucariotos/metabolismo , Fator de Iniciação Eucariótico 4G/metabolismo , Fatores de Iniciação em Eucariotos/fisiologia , Regulação Fúngica da Expressão Gênica , Saccharomyces cerevisiae/metabolismo , Cristalografia por Raios X/métodos , Fatores de Iniciação em Eucariotos/química , Polarização de Fluorescência/métodos , Modelos Moleculares , Conformação Molecular , Mutação , Fenótipo , Plasmídeos/metabolismo , Ligação Proteica , Biossíntese de Proteínas , Mapeamento de Interação de Proteínas , Proteínas Recombinantes/química
9.
bioRxiv ; 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-37986768

RESUMO

We have developed a deep sequencing-based approach, Rec-Seq, that allows simultaneous monitoring of ribosomal 48S pre-initiation complex (PIC) formation on every mRNA in the translatome in an in vitro reconstituted system. Rec-Seq isolates key early steps in translation initiation in the absence of all other cellular components and processes. Using this approach we show that the DEAD-box ATPase Ded1 promotes 48S PIC formation on the start codons of >1000 native mRNAs, most of which have long, structured 5'-untranslated regions (5'UTRs). Remarkably, initiation measured in Rec-Seq was enhanced by Ded1 for most mRNAs previously shown to be highly Ded1-dependent by ribosome profiling of ded1 mutants in vivo, demonstrating that the core translation functions of the factor are recapitulated in the purified system. Our data do not support a model in which Ded1acts by reducing initiation at alternative start codons in 5'UTRs and instead indicate it functions by directly promoting mRNA recruitment to the 43S PIC and scanning to locate the main start codon. We also provide evidence that eIF4A, another essential DEAD-box initiation factor, is required for efficient PIC assembly on almost all mRNAs, regardless of their structural complexity, in contrast to the preferential stimulation by Ded1 of initiation on mRNAs with long, structured 5'UTRs.

10.
Elife ; 132024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38573742

RESUMO

We have developed a deep sequencing-based approach, Rec-Seq, that allows simultaneous monitoring of ribosomal 48S preinitiation complex (PIC) formation on every mRNA in the translatome in an in vitro reconstituted system. Rec-Seq isolates key early steps in translation initiation in the absence of all other cellular components and processes. Using this approach, we show that the DEAD-box ATPase Ded1 promotes 48S PIC formation on the start codons of >1000 native mRNAs, most of which have long, structured 5'-untranslated regions (5'UTRs). Remarkably, initiation measured in Rec-Seq was enhanced by Ded1 for most mRNAs previously shown to be highly Ded1-dependent by ribosome profiling of ded1 mutants in vivo, demonstrating that the core translation functions of the factor are recapitulated in the purified system. Our data do not support a model in which Ded1acts by reducing initiation at alternative start codons in 5'UTRs and instead indicate it functions by directly promoting mRNA recruitment to the 43S PIC and scanning to locate the main start codon. We also provide evidence that eIF4A, another essential DEAD-box initiation factor, is required for efficient PIC assembly on almost all mRNAs, regardless of their structural complexity, in contrast to the preferential stimulation by Ded1 of initiation on mRNAs with long, structured 5'UTRs.


Assuntos
RNA Helicases DEAD-box , Transcriptoma , Regiões 5' não Traduzidas , Códon de Iniciação , RNA Mensageiro/genética
11.
Int J Biol Macromol ; 270(Pt 1): 132209, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38729471

RESUMO

Recently, the chitosan (CS)-based composites have attracted increasing attention for controlling and preventing the spread of pathogenic microorganisms. Herein, an amphiphilic copolymer containing epoxy and quaternary ammonium groups (PBGDBr) was synthesized via three common acrylate monomers. The epoxy groups of this copolymer were then crosslinked with the amino groups of CS to synthesize a natural/synthetic (PBGDBr-C) composite to increase the water solubility of CS under alkaline conditions and enhance its antibacterial activity based on chemical contact-type modes. Moreover, silver bromide nanoparticles (AgBr NPs)-decorated PBGDBr-C (AgBr@PBGDBr-C) composite was prepared, which aimed to endow the final AgBr@PBGDBr-C composite with a photodynamic antibacterial mode relying on the formation of Ag/AgBr nanostructures catalyzed by visible light on AgBr NPs. The results showed that the final composite possessed satisfactory bactericidal effects at concentrations higher than 64 and 128 µg/mL against Escherichia coli and Staphylococcus aureus, respectively. Additionally, The L929 cells treated with the final composite retained high cell viability (>80 %) at a concentration of 128 µg/mL, indicating its low toxicity to L929 cells. Overall, our synthetic strategy exploits a multi-modal system that enables chemical-photodynamic synergies to treat infections caused by pathogenic bacteria while delaying the development of bacterial resistance.


Assuntos
Antibacterianos , Brometos , Quitosana , Escherichia coli , Compostos de Prata , Staphylococcus aureus , Quitosana/química , Quitosana/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/síntese química , Brometos/química , Brometos/farmacologia , Compostos de Prata/química , Compostos de Prata/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Polímeros/química , Polímeros/farmacologia , Camundongos , Cátions/química , Nanopartículas/química , Nanopartículas Metálicas/química , Animais , Sobrevivência Celular/efeitos dos fármacos , Linhagem Celular
12.
Biomarkers ; 18(3): 236-41, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23488625

RESUMO

The objective of this study was to evaluate the association between MDR1 gene polymorphisms and hepatocellular carcinoma (HCC) risk. Genomic DNA of 1431 subjects was extracted from peripheral blood and genotyping was performed using the created restriction site-polymerase chain reaction (CRS-PCR). We found that the c.1465C > T single nucleotide polymorphisms (SNP) increased HCC risk in all genetic models (p < 0.05) and the allele-T of c.1465C > T may contribute to the risk of HCC. No significantly increased HCC risk was detected in c.159G > T SNP. Our data indicated that the genetic variants of MDR1 gene may be a valuable molecular marker for HCC.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , Polimorfismo de Nucleotídeo Único , Subfamília B de Transportador de Cassetes de Ligação de ATP , Idoso , Alelos , Povo Asiático , Biomarcadores/metabolismo , Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/etnologia , Estudos de Casos e Controles , Feminino , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Desequilíbrio de Ligação , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/etnologia , Masculino , Pessoa de Meia-Idade , Modelos Genéticos , Risco
13.
Environ Sci Pollut Res Int ; 30(13): 38363-38379, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36580246

RESUMO

This study attempts to examine how urban agglomerations establish sustainable environmental collaborative governance. To achieve this goal, the qualitative comparative analysis method is used to explore the conditions and models for urban agglomerations to establish environmental collaborative governance, with 12 urban agglomerations approved by the Chinese authorities as examples. Based on the collaborative governance framework, this paper proposes six starting conditions that affect the establishment of urban agglomeration collaboration: vertical intervention, horizontal cooperation, leadership attention, governance capacity, initial pollution, and economic governance. The interaction of these conditions was tested in the practice of environmental cooperation in urban agglomerations. The results show that horizontal cooperation, leadership attention, and economic governance are necessary conditions for the establishment of urban agglomeration cooperation. The authority-driven mode, capability-driven mode, and pressure-driven mode can promote cooperation. Vertical intervention, governance capacity, and initial pollution constitute the external and internal driving forces of urban agglomeration cooperation. These findings supplement the literature on urban agglomeration collaboration and provide policy makers with insight into sustainable urban agglomeration collaborative environmental governance.


Assuntos
Conservação dos Recursos Naturais , Urbanização , Política Ambiental , China , Poluição Ambiental , Desenvolvimento Econômico , Cidades
14.
Front Public Health ; 11: 1136640, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37033087

RESUMO

Major production safety accidents have become the key obstacle to improve the overall safety production level. Analyzing the causal relationship of major production safety accidents is helpful to clarify its characteristics and laws. Based on the literature, the analytical framework of "individual - technology - management - environment" is proposed. Taking 37 production safety accidents as samples, fuzzy set qualitative comparative analysis (fsQCA) is used to analyze the occurrence path and mechanism of major production safety accidents. The results show that: (1) Major production safety accidents are the result of multiple factors coupling. Minor external supervision or abnormal production behaviors are more likely to cause major production safety accidents. (2) When the production behavior is abnormal and the safety management ability is insufficient, major production safety accidents are more likely to occur. (3) There are five ways and three mechanisms for major production safety accidents. This work enriches the cognition of causality of production safety accidents from the perspective of configuration, clearly shows which variable combinations lead to major accidents, and helps to prevent and reduce major production safety accidents and their risks.


Assuntos
Acidentes , Saúde Ocupacional , Gestão da Segurança , Humanos
15.
Front Public Health ; 11: 1167379, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37415713

RESUMO

Background: Myopia is an increasingly serious public concern, particularly among primary school students. The prevalence of myopia and its influencing factors in primary school pupils in Eastern China during the COVID-19 pandemic had not been explored. Methods: A randomly clustered sampling method was performed, and selected pupils from grade 1 to grade 3 in 15 primary schools in the Fenghua District of Zhejiang Province were included and given myopia screening and uniform questionnaire survey 1 year later. Results: A total of 4,213 students completed the myopia screening and questionnaire survey. Myopia was diagnosed in 1,356 pupils, with a myopia incidence of 32.19%. The spherical equivalent (SE) refraction of the included pupils decreased on average by 0.50 ± 2.15 D 1 year later. The myopia rate was positively correlated with the increase of grade, in which the myopia rate among grade 3 students was the highest at 39.69%. The myopia rate among female students was higher than that among male students. Students residing in urban areas had a higher myopia rate than in rural areas. Maintaining an near work distance ≥33 cm was a significant protective factor (OR = 0.84, 95% CI: 0.74-0.96). Students with two myopic parents had a higher risk of myopia (OR = 1.61, 95% CI: 1.34-1.92). Conclusion: During the COVID-19 pandemic, the myopia rate among early primary school students in Eastern China was high. More attention and implementation of interventions from health and education departments, such as training the development of good eye behavior, should be considered to strengthen the intervention of myopia in primary school students.


Assuntos
COVID-19 , Miopia , Humanos , Masculino , Feminino , Pandemias , COVID-19/epidemiologia , Miopia/epidemiologia , China/epidemiologia , Estudantes
16.
RNA ; 16(4): 748-61, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20179149

RESUMO

Upstream open reading frames (uORFs) are protein coding elements in the 5' leader of messenger RNAs. uORFs generally inhibit translation of the main ORF because ribosomes that perform translation elongation suffer either permanent or conditional loss of reinitiation competence. After conditional loss, reinitiation competence may be regained by, at the minimum, reacquisition of a fresh methionyl-tRNA. The conserved h subunit of Arabidopsis eukaryotic initiation factor 3 (eIF3) mitigates the inhibitory effects of certain uORFs. Here, we define more precisely how this occurs, by combining gene expression data from mutated 5' leaders of Arabidopsis AtbZip11 (At4g34590) and yeast GCN4 with a computational model of translation initiation in wild-type and eif3h mutant plants. Of the four phylogenetically conserved uORFs in AtbZip11, three are inhibitory to translation, while one is anti-inhibitory. The mutation in eIF3h has no major effect on uORF start codon recognition. Instead, eIF3h supports efficient reinitiation after uORF translation. Modeling suggested that the permanent loss of reinitiation competence during uORF translation occurs at a faster rate in the mutant than in the wild type. Thus, eIF3h ensures that a fraction of uORF-translating ribosomes retain their competence to resume scanning. Experiments using the yeast GCN4 leader provided no evidence that eIF3h fosters tRNA reaquisition. Together, these results attribute a specific molecular function in translation initiation to an individual eIF3 subunit in a multicellular eukaryote.


Assuntos
Regiões 5' não Traduzidas , Fator de Iniciação 3 em Eucariotos/metabolismo , Fases de Leitura Aberta , Iniciação Traducional da Cadeia Peptídica , Subunidades Proteicas/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Códon de Iniciação , Fator de Iniciação 3 em Eucariotos/genética , Mutação , Biossíntese de Proteínas , Subunidades Proteicas/genética , RNA Mensageiro/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
17.
Front Public Health ; 10: 906715, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35664095

RESUMO

Background: With the emergence of the metaverse, virtual reality, as a digital technology, must be getting hotter. High quality virtual reality related nursing knowledge scene learning is gradually replacing traditional education and intervention skills. Objective: This systematic study aimed to gain insights into the overall application of virtual reality technology in the study of nursing. Methods: Citations downloaded from the Web of Science Core Collection database for use in VR in nursing publications published from January 1, 2012, to December 31, 2021, were considered in the research. Information retrieval was analyzed using https://bibliometric.com/app, CiteSpace.5.8. R3, and VOS viewer. Results: A total of 408 institutions from 95 areas contributed to relevant publications, of which the United States is the most influential country in this research field. The clustering labels of cited documents were obtained from the citing documents. Virtual simulation, virtual learning, clinical skills, and dementia are the clustering labels of co-cited documents. The burst keywords represented the research frontiers in 2020-2021, which were knowledge and simulation. Conclusion: Virtual nursing has had an impact on both nurses and clients. With the emergence of the concept of the metaverse, the research and application of virtual reality technology in nursing will gradually increase.


Assuntos
Bibliometria , Realidade Virtual , Competência Clínica , Simulação por Computador , Bases de Dados Factuais , Humanos , Estados Unidos
18.
Front Public Health ; 10: 925475, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36117596

RESUMO

Background: Autism spectrum disorders (ASD) are heterogeneous neurodevelopmental conditions that affect people worldwide. Early diagnosis and clinical support help achieve good outcomes. However, medical system structure and restricted resource availability create challenges that increase the risk of poor outcomes. Understanding the research progress of childhood ASD in recent years, based on clinical literature reports, can give relevant researchers and rehabilitation therapists more resonable research guides. Objective: This bibliometric study aimed to summarize themes and trends in research on childhood ASD and to suggest directions for future enquiry. Methods: Citations were downloaded from the Web of Science Core Collection database on childhood ASD published from 1 January 2012, to 31 December 2021. The retrieved information was analyzed using CiteSpace.5.8. R3, and VOS viewer. Results: A total of 7,611 papers were published across 103 areas. The United States was the leading source of publications. The clusters that have continued into 2020 include coronavirus disease 2019, gut microbiota, and physical activity, which represent key research topics. Keywords with frequency spikes during 2018-2021 were "disabilities monitoring network," "United States," and "caregiver." Conclusions: The Autism and Developmental Disabilities Monitoring Network in the United States can be used as a reference for relevant workers worldwide. An intelligent medical assistant system is being developed. Further studies are required to elucidate challenges associated with caring for a child with ASD.


Assuntos
Transtorno do Espectro Autista , COVID-19 , Microbioma Gastrointestinal , Bibliometria , COVID-19/epidemiologia , Criança , Bases de Dados Factuais , Humanos , Estados Unidos
19.
Exp Ther Med ; 24(2): 494, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35813312

RESUMO

Dyslipidemia is an umbrella term for a range of lipid metabolic disorders in the body. This condition has been widely reported to greatly increase the risk of cardiovascular diseases, threatening human health. In recent years, advances in molecular biology have deepened understanding of the dyslipidemia-related signaling pathways and specific mechanisms underlying dyslipidemia. Signaling pathways possess the ability to transmit an extracellular signal to the inside of the cell, leading to specific biological effects. Lipid metabolism disorders and lipid levels in the blood are frequently affected by aberrant alterations in the dyslipidemia-related signaling pathways. Therefore, further investigations into these pathways are required for the prevention and treatment of dyslipidemia. The present review summarizes the characteristics of six dyslipidemia-associated signaling pathways: Peroxisome proliferator-activated receptor, adenosine monophosphate-activated protein kinase, farnesoid X receptor, forkhead box O, adipocytokine and cyclic adenosine monophosphate signaling pathways. In particular, specific focus was placed on previous experimental studies and reports on the intervention effects of natural substances (compounds from animals, plants, marine organisms and microorganisms) on dyslipidemia.

20.
Front Public Health ; 10: 1029392, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36276341

RESUMO

Objective: We aimed to explore the impact of using virtual reality technology to intervene in and encourage the developmental behavior areas of cognition, imitation, and social interaction in children with autism spectrum disorder. Methods: Forty-four children with autism spectrum disorder were divided randomly into an intervention group and a control group, with each group consisting of 22 participants. Incorporating conventional rehabilitation strategies, virtual reality technology was used with the intervention group to conduct rehabilitation training in areas including cognition, imitation, and social interaction. The control group was provided conventional/routine clinical rehabilitation training. The children's cognitive development was evaluated before and 3 months after intervention. Results: After intervention, the developmental abilities of both groups of children in the areas of cognition, imitation, and social interaction were improved over their abilities measured before the intervention (P < 0.05). However, post-intervention score differences between the two groups demonstrated that the intervention group levels were better than the control group levels only in the areas of cognition and social interaction (P < 0.05). Conclusion: Combining virtual reality with conventional rehabilitation training improved the cognitive and social development of children with autism spectrum disorder and supported the goal of improving the rehabilitation effect.


Assuntos
Transtorno do Espectro Autista , Realidade Virtual , Criança , Humanos , Comunicação , Cognição , Tecnologia
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