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1.
Nat Prod Res ; 38(1): 103-111, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-35929965

RESUMO

ABSTACTA chemical investigation of the endophyte Penicillium sp. Nb 19, isolated from leaves of the traditionally medical plant Baphicacanthus cusia (Nees) Bremek., yielded one new indole diterpenoid, 7-methoxy-13-dehydroxypaxilline (1) together with seven known metabolites (2-8). The obtained structure of compound 1 was elucidated by its spectroscopic data. In addition, the absolute configuration of compound 6 was confirmed by ECD for the first time. Compounds 1-6 were evaluated for antitumor activity against MCF-7, HepG2, and HCCC-9810 cell lines.


Assuntos
Diterpenos , Penicillium , Nióbio/metabolismo , Diterpenos/química , Fungos , Indóis/química , Penicillium/química , Estrutura Molecular
2.
Appl Biochem Biotechnol ; 195(4): 2709-2718, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36074237

RESUMO

Antibodies are a useful tool for assistance to map the binding epitopes in Bacillus thuringiensis Cry toxins and their receptors, and even determine how receptors promote toxicity. In this work, a monoclonal antibody (mAb-1D2) was produced by the hybridoma cell line raised against Cry2Aa toxins, with a half inhibition concentration (IC50) of 9.16 µg/mL. The affinity constant of two recombinant toxin-binding fragments derived from Helicoverpa armigera and Plutella xylostella cadherin-like protein (HaCad-TBR or PxCad-TBR) to Cry2Aa toxin was measured to be 1.21 µM and 1.24 µM, respectively. Competitive ELISA showed that mAb-1D2 competed with HaCad-TBR or PxCad-TBR binding to Cry2Aa. Meanwhile, the toxicity of the Cry2Aa toxin to the H. armigera and P. xylostella larvae were greatly reduced when the toxin was mixed with mAb-1D2, which indicated that cadherin may play an important functional role in the toxicity of Cry2Aa. After transforming mAb-1D2 to a single-chain variable fragment (scFv), the hot spot residues of Cry2Aa with 1D2-scFv, PxCad-TBR, and HaCad-TBR were analyzed by molecular docking. It was demonstrated that the hot spot residues of Cry2Aa involving with 1D2-scFv interaction were mainly in Domain II, and some residues in Domain I. Moreover, mAb-1D2 and the two cadherin fragments shared the common hot spot residues on Cry2Aa, which could explain mAb-1D2 inhibited Cry2Aa binding with cadherin fragments. This monoclonal antibody could be a useful tool for identifying the binding epitopes between Cry2Aa and cadherin, and even assist to analyze the roles of cadherin in Cry2Aa toxicity.


Assuntos
Bacillus thuringiensis , Mariposas , Animais , Bacillus thuringiensis/metabolismo , Endotoxinas/toxicidade , Endotoxinas/metabolismo , Caderinas/química , Caderinas/metabolismo , Anticorpos Monoclonais , Epitopos/análise , Epitopos/química , Epitopos/metabolismo , Simulação de Acoplamento Molecular , Toxinas de Bacillus thuringiensis/metabolismo , Larva , Proteínas Hemolisinas/toxicidade , Proteínas Hemolisinas/química , Proteínas Hemolisinas/metabolismo , Proteínas de Bactérias/química
3.
Zhongguo Zhong Yao Za Zhi ; 45(14): 3467-3474, 2020 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-32726063

RESUMO

Resin-containing drugs in Dracaena from four different appearances were analyzed by headspace sampling-gas chromatography-mass spectrometry(HS-GC-MS) metabolomics technique and hierarchical clustering analysis(HCA) chemometrics method. This study was to analyze differential volatile components in resin-containing drugs in Dracaena from different appearance and metabolic pathways. The results of partial least squares discriminant analysis(PLS-DA) and HCA analysis indicated that there was little difference in volatile components between fiber-rich sample and hollow cork cambium sample, however, the volatile components in the two samples compared with whole body resin-containing sample and resin-secreting aggregated sample had a large metabolic difference. Twenty differential metabolites were screened by VIP and P values of PLS-DA. The content of these differential metabolites was significantly higher in whole body resin-containing sample and resin-secreting aggregated sample than in fiber-rich sample and hollow cork cambium sample. Sixteen significant metabolic pathways were obtained through enrichment analysis(P<0.05), mainly involved in terpenoids biosynthesis and phenylpropanoid metabolism. This result provided a reference for further study of resin formation mechanism of resin-containing drugs in Dracaena from different appearances. At the same time, it also provided a reference for establishing a multi-index quality evaluation system.


Assuntos
Dracaena , Análise por Conglomerados , Análise Discriminante , Cromatografia Gasosa-Espectrometria de Massas , Resinas Vegetais
4.
J Anesth ; 32(1): 77-81, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29164334

RESUMO

PURPOSE: Preoperative sleep study helps to predict post-adenotonsillectomy morphine requirements. However, in some institutions, many suspected children with obstructive sleep apnoea syndrome have an adenotonsillectomy without polysomnography assessments. This study investigated the relationship between the results of a fentanyl test performed before extubation and the postoperative morphine requirements in children after adenotonsillectomy. METHODS: Intravenous fentanyl (1 µg/kg) was given as a test before extubation when spontaneous ventilation was restored in 80 children aged 3-7 years who underwent adenotonsillectomy. The result was considered positive if the patient's respiratory rate decreased >50% after the test. In the recovery room, pain was assessed every 10 min using the Children's Hospital of Eastern Ontario Pain Scale. Rescue morphine (10 µg/kg) was given when the score was ≥6. RESULTS: The median [IQR (range)] cumulative morphine consumption rates for children with a positive result (n = 25) and a negative result (n = 52) were 30 (20, 40) and 50 (40, 50) µg/kg, respectively (P = 0.002). Eighty-eight percent of the positive-result patients and 48% of the negative-result patients were light consumers of morphine (cumulative dose <50 µg/kg) (P = 0.001). CONCLUSIONS: We conclude that children with a positive result after a fentanyl test require less morphine to achieve comfort than those with a negative result. CLINICALTRIALS. GOV ID: NCT02484222.


Assuntos
Adenoidectomia/métodos , Fentanila/administração & dosagem , Morfina/administração & dosagem , Tonsilectomia/métodos , Extubação , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Medição da Dor , Polissonografia , Período Pós-Operatório , Apneia Obstrutiva do Sono/complicações
5.
Nat Commun ; 7: 13181, 2016 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-27734958

RESUMO

A double-negative feedback loop formed by the morning genes CIRCADIAN CLOCK ASSOCIATED1 (CCA1)/LATE ELONGATED HYPOCOTYL (LHY) and the evening gene TIMING OF CAB EXPRESSION1 (TOC1) contributes to regulation of the circadian clock in Arabidopsis. A 24-h circadian cycle starts with the peak expression of CCA1 at dawn. Although CCA1 is targeted by multiple transcriptional repressors, including PSEUDO-RESPONSE REGULATOR9 (PRR9), PRR7, PRR5 and CCA1 HIKING EXPEDITION (CHE), activators of CCA1 remain elusive. Here we use mathematical modelling to infer a co-activator role for LIGHT-REGULATED WD1 (LWD1) in CCA1 expression. We show that the TEOSINTE BRANCHED 1-CYCLOIDEA-PCF20 (TCP20) and TCP22 proteins act as LWD-interacting transcriptional activators. The concomitant binding of LWD1 and TCP20/TCP22 to the TCP-binding site in the CCA1 promoter activates CCA1. Our study reveals activators of the morning gene CCA1 and provides an action mechanism that ensures elevated expression of CCA1 at dawn to sustain a robust clock.


Assuntos
Antocianinas/genética , Proteínas de Arabidopsis/genética , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Proteínas Circadianas Period/genética , Fatores de Transcrição/genética , Antocianinas/metabolismo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Sítios de Ligação/genética , Modelos Genéticos , Proteínas Circadianas Period/metabolismo , Regiões Promotoras Genéticas/genética , Ligação Proteica , Fatores de Transcrição/metabolismo
6.
Sci Rep ; 6: 29246, 2016 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-27385592

RESUMO

It has been demonstrated that Src could modulate NMDA receptor, and PAR1 could also affect NMDAR signaling. However, whether PAR1 could regulate NMDAR through Src under ICH has not yet been investigated. In this study, we demonstrated the role of Src-PSD95-GluN2A signaling cascades in rat ICH model and in vitro thrombin challenged model. Using the PAR1 agonist SFLLR, antagonist RLLFS and Src inhibitor PP2, electrophysiological analysis showed that PAR1 regulated NMDA-induced whole-cell currents (INMDA) though Src in primary cultured neurons. Both in vivo and in vitro results showed the elevated phosphorylation of tyrosine in Src and GluN2A and enhanced interaction of the Src-PSD95-GluN2A under model conditions. Treatment with the PAR1 antagonist RLLFS, AS-PSD95 (Antisense oligonucleotide against PSD95) and Src inhibitor PP2 inhibited the interaction among Src-PSD95-GluN2A, and p-Src, p-GluN2A. Co-application of SFLLR and AS-PSD95, PP2, or MK801 (NMDAR inhibitor) abolished the effect of SF. In conclusion, our results demonstrated that activated thrombin receptor PAR1 induced Src activation, enhanced the interaction among Src-PSD95-GluN2A signaling modules, and up-regulated GluN2A phosphorylation after ICH injury. Elucidation of such signaling cascades would possibly provide novel targets for ICH treatment.


Assuntos
Hemorragia Cerebral/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Quinases da Família src/metabolismo , Animais , Masculino , Neurônios/metabolismo , Fosforilação/fisiologia , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/fisiologia , Trombina/metabolismo , Ativação Transcricional/fisiologia , Tirosina/metabolismo , Regulação para Cima/fisiologia
7.
Pharm Biol ; 54(10): 2304-11, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26987389

RESUMO

Context Qiancao Naomaitong Mixture (QNM) is mainly used to treat ischemic stroke patients in the clinic. Objective This study evaluates the protective effect of QNM on neuronal damage in vitro, and clarifies the underlying mechanism against cerebral ischemia-reperfusion (I/R) injury in vivo. Materials and methods Activity assay of caspase 3 (C-3) and caspase 8 (C-8) were measured with microplate reader and cell apoptosis was investigated. Cerebral I/R injury was induced by MCAO model. QNM groups were given at 0.27, 0.54 and 1.08 mL/100 g body weight. The weight ratio of cerebral infarction tissue was obtained. The cytokine levels in serum and brain tissue were measured using ELISA. Results Compared with the OGD group (C-3: 29.69 ± 5.63, C-8: 74.05 ± 6.86), 100 mg/mL QNM (C-3: 19.80 ± 2.62, C-8: 48.94 ± 6.41) and 200 mg/mL QNM (C-3: 16.28 ± 4.55, C-8: 41.08 ± 4.05) treatments decreased C-3 and C-8 activities significantly, and inhibited apoptosis of SH-SY5Y cells. The weight ratios of cerebral tissues in low, medium and high dose groups were 17.33 ± 5.1%, 17.78 ± 5.4% and 14.25 ± 4.2%, respectively, significantly lower than in control group. QNM also improved the cytokine levels in serum and brain tissue. In addition, histological examination indicated that dense neuropil and largely surviving neurons were seen in treated rats. Conclusion QNM exerted protective effect by inhibiting the cell apoptosis in vitro. The protective mechanisms of QNM were associated with its properties of anti-apoptosis and antioxidation as well as improved neuronal nutrition in I/R rats.


Assuntos
Encéfalo/efeitos dos fármacos , Medicamentos de Ervas Chinesas/farmacologia , Infarto da Artéria Cerebral Média/tratamento farmacológico , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Traumatismo por Reperfusão/prevenção & controle , Animais , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Linhagem Celular Tumoral , Citocinas/sangue , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Humanos , Infarto da Artéria Cerebral Média/sangue , Infarto da Artéria Cerebral Média/patologia , Fator de Crescimento Neural/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Estresse Oxidativo/efeitos dos fármacos , Fitoterapia , Plantas Medicinais , Ratos , Ratos Sprague-Dawley , Traumatismo por Reperfusão/sangue , Traumatismo por Reperfusão/patologia
8.
Zhongguo Zhong Yao Za Zhi ; 41(9): 1608-1616, 2016 May.
Artigo em Chinês | MEDLINE | ID: mdl-28891607

RESUMO

In recent years, with the price rise of Amomum villosum, the quality of A. villosum in the market has been in disorder. To understand the quality status of A. villosum in the market and provide reference for the commercial size fifty-seven samples were collected from different producing areas or markets from August 2013. The samples were detected with evaluation on appearance quality, determination of the contents of bornyl acetate, determination of pesticide residues and heavy metals residues based on Chinese Pharmacopoeia 2015. The results showed that the pesticide residues and heavy metals residues met the requirments, all the samples from different producing areas were qualified except one sample from Fujian province. The qualified rate of native products and imports products samples from market were 43.75% and 14.29%, respectively, the qualified rate of the samples of Yunnan province from producing areas was higher than that from the market. There are two ports at the national level in Yunnan province, where the southern herbs from. A. villosumis one of import medicines from Southeast Asia, and lots of A. villosum samples import to China from Yunnan ports. Most of pharmacists believed that all of the samples from Yunnan province produced in Yunnan. The great majority of commercial species was A. villosum, but A. longiliglare was scarce. Through the survey, it isfound that the main factors affecting the quality of Amomi Fructus was source, lots of A. villosum samples have been replaced by the Amomi Fructus, so the source of imports Amomi Fructus was not clear, which was also more difficult to identify. The quality of A. villosum needs to protect, optimize germplasm, strict control of medicinal sources, specification for medicinal harvesting and processing technology.


Assuntos
Amomum , Medicamentos de Ervas Chinesas/normas , China , Frutas , Controle de Qualidade
9.
Ultrason Sonochem ; 26: 81-86, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25605585

RESUMO

Lactic acid has been used as a bio-based green solvent to study the ultrasound-assisted scale-up synthesis. We report here, for the first time, on the novel and scalable process for synthesis of pyrrole derivatives in lactic acid solvent under ultrasonic radiation. Eighteen pyrrole derivatives have been synthesized in lactic acid solvent under ultrasonic radiation and characterized by (1)H NMR, IR, ESI MS. The results show, under ultrasonic radiation, lactic acid solvent can overcome the scale-up challenges and exhibited many advantages, such as bio-based origin, shorter reaction time, lower volatility, higher yields, and ease of isolating the products.


Assuntos
Química Verde/métodos , Ácido Láctico/química , Pirróis/química , Pirróis/síntese química , Solventes/química , Ondas Ultrassônicas , Técnicas de Química Sintética
10.
J Recept Signal Transduct Res ; 35(6): 523-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25264226

RESUMO

It has been well documented that Momordica charantia polysaccharide (MCP) has multiple biological effects such as immune enhancement, anti-oxidation and anti-cancer. However, the potential protective effects of MCP on stroke damage and its relative mechanisms remain unclear. Our present study demonstrated that MCP could scavenge reactive oxygen species (ROS) in intra-cerebral hemorrhage damage, significantly attenuating the neuronal death induced by thrombin in primary hippocampal neurons. Furthermore, we found that MCP prevented the activation of the c-Jun N-terminal protein kinase (JNK3), c-Jun and caspase-3, which was caused by the intra-cerebral hemorrhage injury. Taken together, our study demonstrated that MCP had a neuroprotective effect in response to intra-cerebral hemorrhage and its mechanisms involved the inhibition of JNK3 signaling pathway.


Assuntos
Lesões Encefálicas/tratamento farmacológico , Hemorragia Cerebral/complicações , Proteína Quinase 10 Ativada por Mitógeno/metabolismo , Momordica charantia/química , Fármacos Neuroprotetores/farmacologia , Fitoterapia , Polissacarídeos/farmacologia , Animais , Apoptose/efeitos dos fármacos , Western Blotting , Lesões Encefálicas/etiologia , Lesões Encefálicas/metabolismo , Radicais Livres/metabolismo , Immunoblotting , Técnicas Imunoenzimáticas , Imunoprecipitação , Masculino , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos
11.
Plant Cell ; 26(7): 2858-72, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25052717

RESUMO

Light regulates growth and developmental processes in plants via global transcriptome adjustment, translational control, and multilayered posttranslational modification of proteins. The transcriptional activation and repression of light-responsive genes has been well documented; however, the impact of posttranscriptional regulation on conveying light signals has been less addressed. Here, we examined whether optimal photomorphogenesis in Arabidopsis thaliana requires the proper biogenesis of small regulatory RNAs that play pivotal roles in the posttranscriptional regulation of gene expression. Arabidopsis carrying a mutation in HUA ENHANCER1 (HEN1), required for stabilization of small regulatory RNAs, showed defects in multiple aspects of photomorphogenic and skotomorphogenic development. HEN1 negatively regulated Arabidopsis photomorphogenesis. Light-activated HEN1 expression depended on the photoreceptors phytochrome A (phyA), phyB, cryptochrome 1 (cry1), and cry2 and key transcriptional regulators ELONGATED HYPOCOTYL5 (HY5) and HY5-HOMOLOG. We also demonstrate the involvement of the small regulatory RNAs miR157d and miR319 in modulating the expression of a positive regulator, HY5, and negative regulators TEOSINTE BRANCHED1, CYCLOIDEA AND PCF family proteins, respectively, for optimal photomorphogenic development in Arabidopsis.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas/efeitos da radiação , MicroRNAs/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Criptocromos , Luz , MicroRNAs/metabolismo , Mutação , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Fitocromo A/genética , Fitocromo A/metabolismo , Fitocromo B/genética , Fitocromo B/metabolismo , Plântula/genética
12.
Zhong Yao Cai ; 36(1): 122-7, 2013 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-23750419

RESUMO

OBJECTIVE: To obtain the optimal conditions of extraction of Clerodendranthus spicatus and provide the theoretical foundation for its further processing and utilization. METHODS: On the basis of the single factor test, response surface methodology was applied to optimize the extraction conditions. RESULTS: The results showed that extraction time, water-feed ratio, ethanol concentration and extraction temperature all had significant effects on the extraction rate of polysaccharides. The optimal extraction time was 3h, solid-liquid ratio was 50:1, ethanol concentration was 30% and extraction temperature was 80 degrees C. Under these optimized conditions, the extraction rate was 27.71%. CONCLUSION: The extraction technology is simple, reliable and highly predictive.


Assuntos
Cinamatos/análise , Depsídeos/análise , Medicamentos de Ervas Chinesas/isolamento & purificação , Lamiaceae/química , Tecnologia Farmacêutica/métodos , Cromatografia Líquida de Alta Pressão , Cinamatos/isolamento & purificação , Depsídeos/isolamento & purificação , Medicamentos de Ervas Chinesas/química , Etanol/química , Temperatura , Fatores de Tempo , Ácido Rosmarínico
13.
Proc Natl Acad Sci U S A ; 107(34): 15269-74, 2010 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-20643946

RESUMO

The effect of RNA silencing in plants can be amplified if the production of secondary small interfering RNAs (siRNAs) is triggered by the interaction of microRNAs (miRNAs) or siRNAs with a long target RNA. miRNA and siRNA interactions are not all equivalent, however; most of them do not trigger secondary siRNA production. Here we use bioinformatics to show that the secondary siRNA triggers are miRNAs and transacting siRNAs of 22 nt, rather than the more typical 21-nt length. Agrobacterium-mediated transient expression in Nicotiana benthamiana confirms that the siRNA-initiating miRNAs, miR173 and miR828, are effective as triggers only if expressed in a 22-nt form and, conversely, that increasing the length of miR319 from 21 to 22 nt converts it to an siRNA trigger. We also predicted and validated that the 22-nt miR771 is a secondary siRNA trigger. Our data demonstrate that the function of small RNAs is influenced by size, and that a length of 22 nt facilitates the triggering of secondary siRNA production.


Assuntos
Plantas/genética , Plantas/metabolismo , RNA de Plantas/biossíntese , RNA de Plantas/genética , RNA Interferente Pequeno/biossíntese , RNA Interferente Pequeno/genética , Arabidopsis/genética , Arabidopsis/metabolismo , Sequência de Bases , Inativação Gênica , MicroRNAs/biossíntese , MicroRNAs/genética , Plantas Geneticamente Modificadas , Rhizobium/genética , Homologia de Sequência do Ácido Nucleico , Nicotiana/genética , Nicotiana/metabolismo
14.
Plant J ; 54(2): 205-19, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18182030

RESUMO

We surveyed differential gene expression patterns during early photomorphogenesis in both wild-type and mutant Arabidopsis defective in HY5, an influential positive regulator of the responses of gene expression to a light stimulus, to identify light-responsive genes whose expression was HY5 dependent. These gene-expression data identified light-regulated zinc finger protein 1 (LZF1), a gene encoding a previously uncharacterized C2C2-CO B-box transcriptional regulator. HY5 has positive trans-activating activity toward LZF1 and binding affinity to LZF1 promoter in vivo. HY5 is needed but not sufficient for the induction of LZF1 expression. Anthocyanin content is significantly diminished in lzf1 under far red, which is the most efficient light for the induction of LZF1. The expression of PAP1/MYB75 is elevated in plants overexpressing LZF1, which leads to the hyperaccumulation of anthocyanin in transgenic Arabidopsis. The transition from etioplast to chloroplast and the accumulation of chlorophyll were notably compromised in the lzf1 mutant. We provide molecular evidence that LZF1 influences chloroplast biogenesis and function via regulating genes encoding chloroplast proteins. In the absence of HY5, mutation of LZF1 leads to further reduced light sensitivity for light-regulated inhibition of hypocotyl elongation and anthocyanin and chlorophyll accumulation. Our data indicate that LZF1 is a positive regulator functioning in Arabidopsis de-etiolation.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , Proteínas Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Fatores de Transcrição de Zíper de Leucina Básica/genética , Cloroplastos/metabolismo , Cloroplastos/ultraestrutura , Regulação para Baixo , Perfilação da Expressão Gênica , Luz , Mutação , Proteínas Nucleares/genética , Proteínas Associadas a Pancreatite , Regiões Promotoras Genéticas , Ligação Proteica , Transdução de Sinais , Fatores de Transcrição/genética , Regulação para Cima
15.
Proc Natl Acad Sci U S A ; 104(9): 3318-23, 2007 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-17360645

RESUMO

Small RNAs play pivotal roles in regulating gene expression in higher eukaryotes. Among them, trans-acting siRNAs (ta-siRNAs) are a class of small RNAs that regulate plant development. The biogenesis of ta-siRNA depends on microRNA-targeted cleavage followed by the DCL4-mediated production of small RNAs phased in 21-nt increments relative to the cleavage site on both strands. To find TAS genes, we have used these characteristics to develop the first computational algorithm that allows for a comprehensive search and statistical evaluation of putative TAS genes from any given small RNA database. A search in Arabidopsis small RNA massively parallel signature sequencing (MPSS) databases with this algorithm revealed both known and previously unknown ta-siRNA-producing loci. We experimentally validated the biogenesis of ta-siRNAs from two PPR genes and the trans-acting activity of one of the ta-siRNAs. The production of ta-siRNAs from the identified PPR genes was directed by the cleavage of a TAS2-derived ta-siRNA instead of by microRNAs as was reported previously for TAS1a, -b, -c, TAS2, and TAS3 genes. Our results indicate the existence of a small RNA regulatory cascade initiated by miR173-directed cleavage and followed by the consecutive production of ta-siRNAs from two TAS genes.


Assuntos
Algoritmos , Arabidopsis/genética , Biologia Computacional/métodos , MicroRNAs/genética , RNA Interferente Pequeno/biossíntese , RNA Interferente Pequeno/genética , Northern Blotting , Primers do DNA , Bases de Dados Genéticas , Ribonuclease III , Ribonucleases/genética
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