The initiation of RNA interference (RNAi) in plants

Hung, Yu-Hung; Slotkin, R. Keith

doi:10.1016/j.pbi.2021.102014

Cited by 87 publications

(56 citation statements)

References 73 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been well documented that activated transposons give rise to epigenetically activated siRNAs (easiRNAs), which mediate both post‐transcriptional RNA interference and de novo DNA methylation at naïve transposons (Creasey et al., 2014; Hung and Slotkin, 2021; Nuthikattu et al., 2013). The biogenesis of easiRNAs is triggered by RDR6, which is colocalized with its interacting partner SUPPRESSOR OF GENE SILENCING3 (SGS3) to discrete cytoplasmic puncta often called siRNA bodies (Jouannet et al., 2012; Kim et al., 2021; Kumakura et al., 2009).…”

Section: Main Textmentioning

confidence: 99%

Phase separation of chromatin and small RNA pathways in plants

2021

View full text Add to dashboard Cite

SUMMARY Gene expression can be modulated by epigenetic mechanisms, including chromatin modifications and small regulatory RNAs. These pathways are unevenly distributed within a cell and usually take place in specific intracellular regions. Unfortunately, the fundamental driving force and biological relevance of such spatial differentiation is largely unknown. Liquid–liquid phase separation (LLPS) is a natural propensity of demixing liquid phases and has been recently suggested to mediate the formation of biomolecular condensates that are relevant to diverse cellular processes. LLPS provides a mechanistic explanation for the self‐assembly of subcellular structures by which the efficiency and specificity of certain cellular reactions are achieved. In plants, LLPS has been observed for several key factors in the chromatin and small RNA pathways. For example, the formation of facultative and obligate heterochromatin involves the LLPS of multiple relevant factors. In addition, phase separation is observed in a set of proteins acting in microRNA biogenesis and the small interfering RNA pathway. In this Focused Review, we highlight and discuss the recent findings regarding phase separation in the epigenetic mechanisms of plants.

show abstract

Section: Main Textmentioning

confidence: 99%

Phase separation of chromatin and small RNA pathways in plants

2021

View full text Add to dashboard Cite

show abstract

“…Several PB proteins were shown to regulate viral infections; Carbon Catabolite Repression 4 (CCR4) facilitates Barley yellow striate mosaic virus replication in barley (Zhang et al ., 2020), VCS supports Potato virus A infection (De et al ., 2020; Hafrén et al ., 2015) and overexpression of several PB components was shown to restrict Turnip Mosaic Virus (Li & Wang, 2018) . It is becoming increasingly evident that RNA surveillance pathways, including RNA silencing and decapping, play a major role in translational regulation not only through degradation of aberrant RNAs, but by eliciting translational repression on endogenous targets (Hung & Slotkin, 2021; Iwakawa et al ., 2020; Wu et al ., 2020; Jang et al ., 2019; Lanet et al ., 2009; Xu & Chua, 2009; Brodersen et al ., 2008). As part of antiviral translational regulation, different animal viruses are frequently challenged with a global shut-down of protein production.…”

Section: Introductionmentioning

confidence: 99%

Cauliflower Mosaic Virus Utilizes Processing Bodies to Escape Translational Repression in Arabidopsis

Hafrén

Hoffmann

Mahboubi

et al. 2021

Preprint

View full text Add to dashboard Cite

Viral infections impose extraordinary RNA stress on a cell, triggering cellular RNA surveillance pathways like RNA decapping, nonsense-mediated decay and RNA silencing. Viruses need to maneuver between these pathways to establish infection and succeed in producing high amounts of viral proteins. Processing bodies (PBs) are integral to RNA triage in eukaryotic cells with several distinct RNA quality control pathways converging for selective RNA regulation. In this study, we investigate the role of Arabidopsis thaliana PBs during Cauliflower Mosaic Virus (CaMV) infection. We find that several PB components are co-opted into viral replication factories and support virus multiplication. This pro-viral role was not associated with RNA decay pathways but instead, we could establish PB components as essential helpers in viral RNA translation. While CaMV is normally resilient to RNA silencing, PB dysfunctions expose the virus to this pathway, similar to previous observations on transgenes. Transgenes, however, undergo RNA Quality Control dependent RNA degradation, whereas CaMV RNA remains stable but becomes translationally repressed through decreased ribosome association, revealing a unique dependence between PBs, RNA silencing and translational repression. Together, our study shows that PB components are co-opted by the virus to maintain efficient translation, a mechanism not associated with canonical PB functions.

show abstract

“…This specificity is achieved when a TE is newly integrated or activated. As a TE becomes transcribed by Pol II, it produces aberrant transcripts, which are the preferred substrates for RNA-dependent RNA polymerases and give rise to primary siRNAs ( 7 , 20 ). Pol V has been recently shown to transcribe broadly and surveil the genome to make it competent to receive the silencing signal from primary siRNA ( 12 ).…”

Section: Introductionmentioning

confidence: 99%

Reinforcement of transcriptional silencing by a positive feedback between DNA methylation and non-coding transcription

Rothi

Tsuzuki

Sethuraman

et al. 2021

Nucleic Acids Research

View full text Add to dashboard Cite

Non-coding transcription is an important determinant of heterochromatin formation. In Arabidopsis thaliana a specialized RNA polymerase V (Pol V) transcribes pervasively and produces long non-coding RNAs. These transcripts work with small interfering RNA to facilitate locus-specific establishment of RNA-directed DNA methylation (RdDM). Subsequent maintenance of RdDM is associated with elevated levels of Pol V transcription. However, the impact of DNA methylation on Pol V transcription remained unresolved. We found that DNA methylation strongly enhances Pol V transcription. The level of Pol V transcription is reduced in mutants defective in RdDM components working downstream of Pol V, indicating that RdDM is maintained by a mutual reinforcement of DNA methylation and Pol V transcription. Pol V transcription is affected only on loci that lose DNA methylation in all sequence contexts in a particular mutant, including mutants lacking maintenance DNA methyltransferases, which suggests that RdDM works in a complex crosstalk with other silencing pathways.

show abstract

The initiation of RNA interference (RNAi) in plants

Cited by 87 publications

References 73 publications

Phase separation of chromatin and small RNA pathways in plants

Phase separation of chromatin and small RNA pathways in plants

Cauliflower Mosaic Virus Utilizes Processing Bodies to Escape Translational Repression in Arabidopsis

Reinforcement of transcriptional silencing by a positive feedback between DNA methylation and non-coding transcription

Contact Info

Product

Resources

About