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1.
Proc Natl Acad Sci U S A ; 109(22): 8505-10, 2012 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-22586116

RESUMO

Intron-containing genes are often transcribed more efficiently than nonintronic genes. The effect of introns on transcription of genes is an evolutionarily conserved feature, being exhibited by such diverse organisms as yeast, plants, flies, and mammals. The mechanism of intron-mediated transcriptional activation, however, is not entirely clear. To address this issue, we inserted an intron in INO1, which is a nonintronic gene, and deleted the intron from ASC1, which contains a natural intron. We then compared transcription of INO1 and ASC1 genes in the presence and absence of an intron. Transcription of both genes was significantly stimulated by the intron. The introns have a direct role in enhancing transcription of INO1 and ASC1 because there was a marked increase in nascent transcripts from these genes in the presence of an intron. Intron-mediated enhancement of transcription required a splicing competent intron. Interestingly, both INO1 and ASC1 were in a looped configuration when their genes contained an intron. Intron-dependent gene looping involved a physical interaction of the promoter and the terminator regions. In addition, the promoter region interacted with the 5' splice site and the terminator with the 3' splice site. Intron-mediated enhancement of transcription was completely abolished in the looping defective sua7-1 strain. No effect on splicing, however, was observed in sua7-1 strain. On the basis of these results, we propose a role for gene looping in intron-mediated transcriptional activation of genes in yeast.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas de Ligação ao GTP/genética , Íntrons/genética , Mio-Inositol-1-Fosfato Sintase/genética , Proteínas de Saccharomyces cerevisiae/genética , Ativação Transcricional , DNA Fúngico/genética , DNA Fúngico/metabolismo , Regulação Fúngica da Expressão Gênica , Mutação INDEL , Mutação , Regiões Promotoras Genéticas/genética , Sítios de Splice de RNA/genética , Splicing de RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Saccharomyces cerevisiae/genética , Regiões Terminadoras Genéticas/genética , Fator de Transcrição TFIIB/genética
2.
Pharmaceutics ; 16(4)2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38675230

RESUMO

Overcoming the limited bioavailability and extensive metabolism of effective in vitro drugs remains a challenge that limits the translation of promising drugs into clinical trials. Resveratrol, despite its well-reported therapeutic benefits, is not metabolically stable and thus has not been utilized as an effective clinical drug. This is because it needs to be consumed in large amounts to overcome the burdens of bioavailability and conversion into less effective metabolites. Herein, we summarize the more relevant approaches to modify resveratrol, aiming to increase its biological and therapeutic efficacy. We discuss combination therapies, derivatization, and the use of resveratrol nanoparticles. Interestingly, the combination of resveratrol with established chemotherapeutic drugs has shown promising therapeutic effects on colon cancer (with oxaliplatin), liver cancer (with cisplatin, 5-FU), and gastric cancer (with doxorubicin). On the other hand, derivatizing resveratrol, including hydroxylation, amination, amidation, imidation, methoxylation, prenylation, halogenation, glycosylation, and oligomerization, differentially modifies its bioavailability and could be used for preferential therapeutic outcomes. Moreover, the encapsulation of resveratrol allows its trapping within different forms of shells for targeted therapy. Depending on the nanoparticle used, it can enhance its solubility and absorption, increasing its bioavailability and efficacy. These include polymers, metals, solid lipids, and other nanoparticles that have shown promising preclinical results, adding more "hype" to the research on resveratrol. This review provides a platform to compare the different approaches to allow directed research into better treatment options with resveratrol.

3.
J Biol Chem ; 284(37): 25015-25, 2009 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-19602510

RESUMO

Gene looping juxtaposes the promoter and terminator regions of RNA polymerase II-transcribed genes in yeast and mammalian cells. Here we report an activator-dependent interaction of transcription initiation and termination factors during gene looping in budding yeast. Chromatin analysis revealed that MET16, INO1, and GAL1p-BUD3 are in a stable looped configuration during activated transcription. Looping was nearly abolished in the absence of transcription activators Met28, Ino2, and Gal4 of MET16, INO1, and GAL1p-BUD3 genes, respectively. The activator-independent increase in transcription was not accompanied by loop formation, thereby suggesting an essential role for activators in gene looping. The activators did not facilitate loop formation directly because they did not exhibit an interaction with the 3' end of the genes. Instead, activators physically interacted with the general transcription factor TFIIB when the genes were activated and in a looped configuration. TFIIB cross-linked to both the promoter and the terminator regions during the transcriptionally activated state of a gene. The presence of TFIIB on the terminator was dependent on the Rna15 component of CF1 3' end processing complex. Coimmunoprecipitation revealed a physical interaction of Rna15 with TFIIB. We propose that the activators facilitate gene looping through their interaction with TFIIB during transcriptional activation of genes.


Assuntos
Transcrição Gênica , Cromatina/química , Imunoprecipitação da Cromatina , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Genes Fúngicos , Modelos Biológicos , Modelos Genéticos , Regiões Promotoras Genéticas , RNA Polimerase II/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Fator de Transcrição TFIIB/metabolismo , Fatores de Transcrição/metabolismo , Fatores de Poliadenilação e Clivagem de mRNA/genética
4.
Curr Protoc Cell Biol ; Chapter 22: Unit22.15, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22968842

RESUMO

Genome architecture plays a significant role in the regulation of DNA-based cellular processes such as transcription and recombination. The successful accomplishment of these processes involves coordinated interaction of DNA elements located at a distance from each other. The 'Chromosome Conformation Capture' (3C) assay is a convenient tool for identification of physical association between spatially separated DNA elements in a cell under physiological conditions. The principle of 3C is to convert physical chromosomal interactions into specific DNA ligation products, which are then detected by PCR. The 3C protocol was originally used to identify long-range, stable chromosomal interactions in yeast. Here we describe a modified 3C procedure that can detect transient, short-range interactions of DNA elements separated by a distance of less than 700 bp. This method has been successfully used to detect dynamic interaction of transcription regulatory elements in yeast and can be used for detecting similar interactions of other genomic regions.


Assuntos
Cromossomos Fúngicos/química , Cromossomos Fúngicos/genética , Densitometria/métodos , Técnicas Genéticas , Reação em Cadeia da Polimerase/métodos , Saccharomyces cerevisiae/genética , Cromatina/química , Cromatina/genética , Cromatina/metabolismo , Cromossomos Fúngicos/metabolismo , Reagentes de Ligações Cruzadas/química , Conformação de Ácido Nucleico , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/metabolismo
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