Gene Silencing Mediated by Small Interfering RNAs in Mammalian Cells

2003 ◽  
Vol 10 (3) ◽  
pp. 245-256 ◽  
Author(s):  
Michaela Scherr ◽  
Michael Morgan ◽  
Matthias Eder
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xiaoyu Yang ◽  
Chenjiang You ◽  
Xufeng Wang ◽  
Lei Gao ◽  
Beixin Mo ◽  
...  

Abstract Background Small RNAs (sRNAs) including microRNAs (miRNAs) and small interfering RNAs (siRNAs) serve as core players in gene silencing at transcriptional and post-transcriptional levels in plants, but their subcellular localization has not yet been well studied, thus limiting our mechanistic understanding of sRNA action. Results We investigate the cytoplasmic partitioning of sRNAs and their targets globally in maize (Zea mays, inbred line “B73”) and rice (Oryza sativa, cv. “Nipponbare”) by high-throughput sequencing of polysome-associated sRNAs and 3′ cleavage fragments, and find that both miRNAs and a subset of 21-nucleotide (nt)/22-nt siRNAs are enriched on membrane-bound polysomes (MBPs) relative to total polysomes (TPs) across different tissues. Most of the siRNAs are generated from transposable elements (TEs), and retrotransposons positively contributed to MBP overaccumulation of 22-nt TE-derived siRNAs (TE-siRNAs) as opposed to DNA transposons. Widespread occurrence of miRNA-mediated target cleavage is observed on MBPs, and a large proportion of these cleavage events are MBP-unique. Reproductive 21PHAS (21-nt phasiRNA-generating) and 24PHAS (24-nt phasiRNA-generating) precursors, which were commonly considered as noncoding RNAs, are bound by polysomes, and high-frequency cleavage of 21PHAS precursors by miR2118 and 24PHAS precursors by miR2275 is further detected on MBPs. Reproductive 21-nt phasiRNAs are enriched on MBPs as opposed to TPs, whereas 24-nt phasiRNAs are nearly completely devoid of polysome occupancy. Conclusions MBP overaccumulation is a conserved pattern for cytoplasmic partitioning of sRNAs, and endoplasmic reticulum (ER)-bound ribosomes function as an independent regulatory layer for miRNA-induced gene silencing and reproductive phasiRNA biosynthesis in maize and rice.


Science ◽  
2015 ◽  
Vol 348 (6230) ◽  
pp. 120-123 ◽  
Author(s):  
Xinyan Zhang ◽  
Ying Zhu ◽  
Xiaodan Liu ◽  
Xinyu Hong ◽  
Yang Xu ◽  
...  

Plant immunity against foreign gene invasion takes advantage of posttranscriptional gene silencing (PTGS). How plants elaborately avert inappropriate PTGS of endogenous coding genes remains unclear. We demonstrate in Arabidopsis that both 5′-3′ and 3′-5′ cytoplasmic RNA decay pathways act as repressors of transgene and endogenous PTGS. Disruption of bidirectional cytoplasmic RNA decay leads to pleiotropic developmental defects and drastic transcriptomic alterations, which are substantially rescued by PTGS mutants. Upon dysfunction of bidirectional RNA decay, a large number of 21- to 22-nucleotide endogenous small interfering RNAs are produced from coding transcripts, including multiple microRNA targets, which could interfere with their cognate gene expression and functions. This study highlights the risk of unwanted PTGS and identifies cytoplasmic RNA decay pathways as safeguards of plant transcriptome and development.


2021 ◽  
Author(s):  
Ganna Reshetnyak ◽  
Jonathan M. Jacobs ◽  
Florence Auguy ◽  
Coline Sciallano ◽  
Lisa Claude ◽  
...  

ABSTRACTNon-coding small RNAs (sRNA) act as mediators of gene silencing and regulate plant growth, development and stress responses. Early insights into plant sRNAs established a role in antiviral defense and they are now extensively studied across plant-microbe interactions. Here, sRNA sequencing discovered a class of sRNA in rice (Oryza sativa) specifically associated with foliar diseases caused by Xanthomonas oryzae bacteria. Xanthomonas-induced small RNAs (xisRNAs) loci were distinctively upregulated in response to diverse virulent strains at an early stage of infection producing a single duplex of 20-22nt sRNAs. xisRNAs production was dependent on the Type III secretion system, a major bacterial virulence factor for host colonization. xisRNA loci overlap with annotated transcripts sequences often encoding protein kinase domain proteins. A number of the corresponding rice cis-genes have documented functions in immune signaling and some xisRNA loci coincide with the coding sequence of a conserved kinase motif. xisRNAs exhibit features of small interfering RNAs and their biosynthesis depend on canonical components OsDCL1 and OsHEN1. xisRNA induction possibly mediates post-transcriptional gene silencing but they do not broadly suppress cis-genes expression on the basis of mRNA-seq data. Overall, our results identify a group of unusual sRNAs with a potential role in plant-microbe interactions.


Author(s):  
Patrick J. Paddison ◽  
Amy A. Caudy ◽  
Ravi Sachidanandam ◽  
Gregory J. Hannon

2021 ◽  
Vol 59 (1) ◽  
Author(s):  
Yongli Qiao ◽  
Rui Xia ◽  
Jixian Zhai ◽  
Yingnan Hou ◽  
Li Feng ◽  
...  

Gene silencing guided by small RNAs governs a broad range of cellular processes in eukaryotes. Small RNAs are important components of plant immunity because they contribute to pathogen-triggered transcription reprogramming and directly target pathogen RNAs. Recent research suggests that silencing of pathogen genes by plant small RNAs occurs not only during viral infection but also in nonviral pathogens through a process termed host-induced gene silencing, which involves trans-species small RNA trafficking. Similarly, small RNAs are also produced by eukaryotic pathogens and regulate virulence. This review summarizes the small RNA pathways in both plants and filamentous pathogens, including fungi and oomycetes, and discusses their role in host–pathogen interactions. We highlight secondary small interfering RNAs of plants as regulators of immune receptor gene expression and executors of host-induced gene silencing in invading pathogens. The current status and prospects of small RNAs trafficking at the host–pathogen interface are discussed. Expected final online publication date for the Annual Review of Phytopathology, Volume 59 is August 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


2019 ◽  
Vol 116 (15) ◽  
pp. 7543-7548 ◽  
Author(s):  
Huan Zhang ◽  
Gozde S. Demirer ◽  
Honglu Zhang ◽  
Tianzheng Ye ◽  
Natalie S. Goh ◽  
...  

Delivery of biomolecules to plants relies onAgrobacteriuminfection or biolistic particle delivery, the former of which is amenable only to DNA delivery. The difficulty in delivering functional biomolecules such as RNA to plant cells is due to the plant cell wall, which is absent in mammalian cells and poses the dominant physical barrier to biomolecule delivery in plants. DNA nanostructure-mediated biomolecule delivery is an effective strategy to deliver cargoes across the lipid bilayer of mammalian cells; however, nanoparticle-mediated delivery without external mechanical aid remains unexplored for biomolecule delivery across the cell wall in plants. Herein, we report a systematic assessment of different DNA nanostructures for their ability to internalize into cells of mature plants, deliver siRNAs, and effectively silence a constitutively expressed gene inNicotiana benthamianaleaves. We show that nanostructure internalization into plant cells and corresponding gene silencing efficiency depends on the DNA nanostructure size, shape, compactness, stiffness, and location of the siRNA attachment locus on the nanostructure. We further confirm that the internalization efficiency of DNA nanostructures correlates with their respective gene silencing efficiencies but that the endogenous gene silencing pathway depends on the siRNA attachment locus. Our work establishes the feasibility of biomolecule delivery to plants with DNA nanostructures and both details the design parameters of importance for plant cell internalization and also assesses the impact of DNA nanostructure geometry for gene silencing mechanisms.


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