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Psychological repression
About: Psychological repression is a research topic. Over the lifetime, 4330 publications have been published within this topic receiving 287917 citations.
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01 Jun 2010
TL;DR: Results show that changes in mRNA levels closely reflect the impact of miRNAs on gene expression and indicate that destabilization of target mRNAs is the predominant reason for reduced protein output.
Abstract: MicroRNAs (miRNAs) are endogenous approximately 22-nucleotide RNAs that mediate important gene-regulatory events by pairing to the mRNAs of protein-coding genes to direct their repression. Repression of these regulatory targets leads to decreased translational efficiency and/or decreased mRNA levels, but the relative contributions of these two outcomes have been largely unknown, particularly for endogenous targets expressed at low-to-moderate levels. Here, we use ribosome profiling to measure the overall effects on protein production and compare these to simultaneously measured effects on mRNA levels. For both ectopic and endogenous miRNA regulatory interactions, lowered mRNA levels account for most (>/=84%) of the decreased protein production. These results show that changes in mRNA levels closely reflect the impact of miRNAs on gene expression and indicate that destabilization of target mRNAs is the predominant reason for reduced protein output.
3,444 citations
TL;DR: The data suggest that two global mechanisms of gene regulation, DNA methylation and histone deacetylation, can be linked by MeCP2, an abundant nuclear protein that is essential for mouse embryogenesis.
Abstract: Cytosine residues in the sequence 5'CpG (cytosine-guanine) are often postsynthetically methylated in animal genomes. CpG methylation is involved in long-term silencing of certain genes during mammalian development and in repression of viral genomes. The methyl-CpG-binding proteins MeCP1 and MeCP2 interact specifically with methylated DNA and mediate transcriptional repression. Here we study the mechanism of repression by MeCP2, an abundant nuclear protein that is essential for mouse embryogenesis. MeCP2 binds tightly to chromosomes in a methylation-dependent manner. It contains a transcriptional-repression domain (TRD) that can function at a distance in vitro and in vivo. We show that a region of MeCP2 that localizes with the TRD associates with a corepressor complex containing the transcriptional repressor mSin3A and histone deacetylases. Transcriptional repression in vivo is relieved by the deacetylase inhibitor trichostatin A, indicating that deacetylation of histones (and/or of other proteins) is an essential component of this repression mechanism. The data suggest that two global mechanisms of gene regulation, DNA methylation and histone deacetylation, can be linked by MeCP2.
3,396 citations
TL;DR: The results establish that the CRISPR system can be used as a modular and flexible DNA-binding platform for the recruitment of proteins to a target DNA sequence, revealing the potential of CRISpri as a general tool for the precise regulation of gene expression in eukaryotic cells.
3,165 citations
TL;DR: In this article, the authors describe principles of miRNA-mRNA interactions and proteins that interact with miRNAs and function in miRNA mediated repression, and discuss the multiple, often contradictory, mechanisms that miRNA have been reported to use, which cause translational repression and mRNA decay.
Abstract: MicroRNAs (miRNAs) are small noncoding RNAs that extensively regulate gene expression in animals, plants, and protozoa. miRNAs function posttranscriptionally by usually base-pairing to the mRNA 3′-untranslated regions to repress protein synthesis by mechanisms that are not fully understood. In this review, we describe principles of miRNA-mRNA interactions and proteins that interact with miRNAs and function in miRNA-mediated repression. We discuss the multiple, often contradictory, mechanisms that miRNAs have been reported to use, which cause translational repression and mRNA decay. We also address the issue of cellular localization of miRNA-mediated events and a role for RNA-binding proteins in activation or relief of miRNA repression.
2,762 citations
TL;DR: The ability of an miRNA to translationally repress a target mRNA is largely dictated by the free energy of binding of the first eight nucleotides in the 5' region of the miRNA, however, G:U wobble base-pairing in this region interferes with activity beyond that predicted on the basis of thermodynamic stability.
Abstract: MicroRNAs (miRNAs) are a class of noncoding RNAs found in organisms as evolutionarily distant as plants and mammals, yet most of the mRNAs they regulate are unknown. Here we show that the ability of an miRNA to translationally repress a target mRNA is largely dictated by the free energy of binding of the first eight nucleotides in the 5' region of the miRNA. However, G:U wobble base-pairing in this region interferes with activity beyond that predicted on the basis of thermodynamic stability. Furthermore, an mRNA can be simultaneously repressed by more than one miRNA species. The level of repression achieved is dependent on both the amount of mRNA and the amount of available miRNA complexes. Thus, predicted miRNA:mRNA interactions must be viewed in the context of other potential interactions and cellular conditions.
1,744 citations