共查询到20条相似文献,搜索用时 31 毫秒
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Small, non-coding RNAs are a distinct class of regulatory RNAs in plants and animals that control a variety of biological processes. In plants, several classes of small RNAs with specific sizes and dedicated functions have evolved through a series of pathways. The major classes of small RNAs include microRNAs (miRNAs) and small interfering RNAs (siRNAs), which differ in their biogenesis. miRNAs control the expression of cognate target genes by binding to reverse complementary sequences, resulting in cleavage or translational inhibition of the target RNAs. siRNAs have a similar structure, function, and biogenesis as miRNAs but are derived from long double-stranded RNAs and can often direct DNA methylation at target sequences. Besides their roles in growth and development and maintenance of genome integrity, small RNAs are also important components in plant stress responses. One way in which plants respond to environmental stress is by modifying their gene expression through the activity of small RNAs. Thus, understanding how small RNAs regulate gene expression will enable researchers to explore the role of small RNAs in biotic and abiotic stress responses. This review focuses on the regulatory roles of plant small RNAs in the adaptive response to stresses. This article is part of a Special Issue entitled: Plant gene regulation in response to abiotic stress. 相似文献
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MicroRNA-directed regulation: to cleave or not to cleave 总被引:1,自引:0,他引:1
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MicroRNAs and other tiny endogenous RNAs in C. elegans 总被引:8,自引:0,他引:8
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Sorting of Drosophila small silencing RNAs 总被引:3,自引:0,他引:3
In Drosophila, small interfering RNAs (siRNAs), which direct RNA interference through the Argonaute protein Ago2, are produced by a biogenesis pathway distinct from microRNAs (miRNAs), which regulate endogenous mRNA expression as guides for Ago1. Here, we report that siRNAs and miRNAs are sorted into Ago1 and Ago2 by pathways independent from the processes that produce these two classes of small RNAs. Such small-RNA sorting reflects the structure of the double-stranded assembly intermediates--the miRNA/miRNA( *) and siRNA duplexes--from which Argonaute proteins are loaded. We find that the Dcr-2/R2D2 heterodimer acts as a gatekeeper for the assembly of Ago2 complexes, promoting the incorporation of siRNAs and disfavoring miRNAs as loading substrates for Drosophila Ago2. A separate mechanism acts in parallel to favor miRNA/miRNA( *) duplexes and exclude siRNAs from assembly into Ago1 complexes. Thus, in flies small-RNA duplexes are actively sorted into Argonaute-containing complexes according to their intrinsic structures. 相似文献
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Endogenous small RNAs and antibacterial immunity in plants 总被引:2,自引:0,他引:2
Jin H 《FEBS letters》2008,582(18):2679-2684
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Construction of small RNA cDNA libraries for deep sequencing 总被引:6,自引:0,他引:6
Small RNAs (21-24 nucleotides) including microRNAs (miRNAs) and small interfering RNAs (siRNAs) are potent regulators of gene expression in both plants and animals. Several hundred genes encoding miRNAs and thousands of siRNAs have been experimentally identified by cloning approaches. New sequencing technologies facilitate the identification of these molecules and provide global quantitative expression data in a given biological sample. Here, we describe the methods used in our laboratory to construct small RNA cDNA libraries for high-throughput sequencing using technologies such as MPSS, 454 or SBS. 相似文献
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Pascal Miesen Alasdair Ivens Amy H. Buck Ronald P. van Rij 《PLoS neglected tropical diseases》2016,10(2)
In Aedes mosquitoes, infections with arthropod-borne viruses (arboviruses) trigger or modulate the expression of various classes of viral and host-derived small RNAs, including small interfering RNAs (siRNAs), PIWI interacting RNAs (piRNAs), and microRNAs (miRNAs). Viral siRNAs are at the core of the antiviral RNA interference machinery, one of the key pathways that limit virus replication in invertebrates. Besides siRNAs, Aedes mosquitoes and cells derived from these insects produce arbovirus-derived piRNAs, the best studied examples being viruses from the Togaviridae or Bunyaviridae families. Host miRNAs modulate the expression of a large number of genes and their levels may change in response to viral infections. In addition, some viruses, mostly with a DNA genome, express their own miRNAs to regulate host and viral gene expression. Here, we perform a comprehensive analysis of both viral and host-derived small RNAs in Aedes aegypti Aag2 cells infected with dengue virus 2 (DENV), a member of the Flaviviridae family. Aag2 cells are competent in producing all three types of small RNAs and provide a powerful tool to explore the crosstalk between arboviral infection and the distinct RNA silencing pathways. Interestingly, besides the well-characterized DENV-derived siRNAs, a specific population of viral piRNAs was identified in infected Aag2 cells. Knockdown of Piwi5, Ago3 and, to a lesser extent, Piwi6 results in reduction of vpiRNA levels, providing the first genetic evidence that Aedes PIWI proteins produce DENV-derived small RNAs. In contrast, we do not find convincing evidence for the production of virus-derived miRNAs. Neither do we find that host miRNA expression is strongly changed upon DENV2 infection. Finally, our deep-sequencing analyses detect 30 novel Aedes miRNAs, complementing the repertoire of regulatory small RNAs in this important vector species. 相似文献
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MicroRNAs (miRNAs) are negative regulators of gene expression in eukaryotic organisms, whereas small interfering RNAs (siRNAs) guide host-cell defence against viruses, transposons and transgenes. A key issue in plant biology is whether miRNAs act only in cells in which they are formed, or if, like siRNAs, they also function after passive diffusion or active transportation into other cells. Recent reports show that miRNAs are indeed able to move between plant cells to direct developmental programming of gene expression. In both leaf and root development, miRNAs establish intercellular gradients of gene expression that are essential for cell and tissue differentiation. Gradients in gene expression also play crucial roles in animal development, and there is strong evidence for intercellular movement of miRNAs in animals. Thus, intercellular movement of miRNAs may be crucial to animal developmental biology as well as plants. 相似文献
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小RNAs作用机制的研究进展 总被引:2,自引:1,他引:1
RNAi的发现引发了生物学的一次革命, 也揭示了一种原来未被发现的, 通过小RNAs(大小~20–30 nt)家族在转录水平或转录后水平调解基因表达的方式。在真核生物中, 这些小RNAs包括siRNAs、miRNAs、piRNAs、scnRNAs、21U-RNAs和其他一些小RNAs等。它们通过调节基因表达来控制细胞的代谢、生长和分化, 维持基因组的完整性, 协调生殖细胞的成熟和抑制病毒对细胞的侵袭以及转座成分的转座。文章综述了这些小RNAs在鉴定和生物合成方面的研究进展, 并讨论了它们对基因表达的调节作用。 相似文献
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Small non-coding RNAs as magic bullets 总被引:6,自引:0,他引:6
Eckstein F 《Trends in biochemical sciences》2005,30(8):445-452
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Mouli Ghosh Dastidar Magdalena Mosiolek Andrea Bleckmann Thomas Dresselhaus Michael D. Nodine Alexis Maizel 《The Plant journal : for cell and molecular biology》2016,88(4):694-702
Small RNAs, such as microRNAs (miRNAs), regulate gene expression and play important roles in many plant processes. Although our knowledge of their biogenesis and mode of action has significantly progressed, we still have comparatively little information about their biological functions. In particular, knowledge about their spatio‐temporal expression patterns rely on either indirect detection by use of reporter constructs or labor‐intensive direct detection by in situ hybridization on sectioned material. None of the current approaches allows a systematic investigation of small RNA expression patterns. Here, we present a sensitive method for in situ detection of miRNAs and siRNAs in intact plant tissues that utilizes both double‐labeled probes and a specific cross‐linker. We determined the expression patterns of several small RNAs in diverse plant tissues. 相似文献
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MicroRNAs: something important between the genes 总被引:10,自引:0,他引:10
Non-coding small endogenous RNAs, of 21-24 nucleotides in length, have recently emerged as important regulators of gene expression in both plants and animals. At least three categories of small RNAs exist in plants: short interfering RNAs (siRNAs) deriving from viruses or transgenes and mediating virus resistance or transgene silencing via RNA degradation; siRNAs deriving from transposons or transgene promoters and controlling transposon and transgene silencing probably via chromatin changes; and microRNAs (miRNAs) deriving from intergenic regions of the genome and regulating the expression of endogenous genes either by mRNA cleavage or translational repression. The disruption of miRNA-mediated regulation causes developmental abnormalities in plants, demonstrating that miRNAs play an important role in the regulation of developmental decisions. 相似文献
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Methylation protects miRNAs and siRNAs from a 3'-end uridylation activity in Arabidopsis 总被引:5,自引:0,他引:5
Small RNAs of 21-25 nucleotides (nt), including small interfering RNAs (siRNAs) and microRNAs (miRNAs), act as guide RNAs to silence target-gene expression in a sequence-specific manner. In addition to a Dicer homolog, DCL1, the biogenesis of miRNAs in Arabidopsis requires another protein, HEN1. miRNAs are reduced in abundance and increased in size in hen1 mutants. We found that HEN1 is a miRNA methyltransferase that adds a methyl group to the 3'-most nucleotide of miRNAs, but the role of miRNA methylation was unknown. Here, we show that siRNAs from sense transgenes, hairpin transgenes, and transposons or repeat sequences, as well as a new class of siRNAs known as trans-acting siRNAs, are also methylated in vivo by HEN1. In addition, we show that the size increase of small RNAs in the hen1-1 mutant is due to the addition of one to five U residues to the 3' ends of the small RNAs. Therefore, a novel uridylation activity targets the 3' ends of unmethylated miRNAs and siRNAs in hen1 mutants. We conclude that 3'-end methylation is a common step in miRNA and siRNA metabolism and likely protects the 3' ends of the small RNAs from the uridylation activity. 相似文献
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Small RNAs have been recently discovered as important regulators of gene expression in Eukaryota. This review compares two
categories of small RNAs existing in plants: short interfering RNAs (siRNAs) and microRNAs (miRNAs) and reveals similarities
and differences between two intriguing processes: RNA degradation and translational repression directed by small RNAs. The
disruption of miRNA-mediated regulation causes developmental abnormalities in plants, proving a fundamental role of miRNAs. 相似文献
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Small RNAs, including microRNAs (miRNAs), small interfering RNAs (siRNAs), and trans-acting siRNAs (ta-siRNAs), mediate gene expression and epigenetic regulation. While siRNAs are highly diverged, miRNAs and ta-siRNAs are generally conserved but many are differentially expressed between related species and in interspecific hybrids and allopolyploids. On one hand, combination of diverged maternal and paternal siRNAs in the same nucleus may exert cis-acting and trans-acting effects on transposable elements (TEs) and TE-associated genes, leading to genomic instability and endosperm and embryo failures, constituting a bottleneck for the evolution of hybrids and polyploids. On the other hand, cis and trans-acting small RNAs induce quantitative and qualitative changes in epigenetic regulation, leading to morphological variation and hybrid vigor in F1 hybrids and stable allopolyploids as well as transgressive phenotypes in the progeny, increasing a potential for adaptive evolution. 相似文献