scholarly journals RNA base-pairing complexity in living cells visualized by correlated chemical probing

2019 ◽  
Vol 116 (49) ◽  
pp. 24574-24582 ◽  
Author(s):  
Anthony M. Mustoe ◽  
Nicole N. Lama ◽  
Patrick S. Irving ◽  
Samuel W. Olson ◽  
Kevin M. Weeks

RNA structure and dynamics are critical to biological function. However, strategies for determining RNA structure in vivo are limited, with established chemical probing and newer duplex detection methods each having deficiencies. Here we convert the common reagent dimethyl sulfate into a useful probe of all 4 RNA nucleotides. Building on this advance, we introduce PAIR-MaP, which uses single-molecule correlated chemical probing to directly detect base-pairing interactions in cells. PAIR-MaP has superior resolution compared to alternative experiments, can resolve multiple sets of pairing interactions for structurally dynamic RNAs, and enables highly accurate structure modeling, including of RNAs containing multiple pseudoknots and extensively bound by proteins. Application of PAIR-MaP to human RNase MRP and 2 bacterial messenger RNA 5′ untranslated regions reveals functionally important and complex structures undetected by prior analyses. PAIR-MaP is a powerful, experimentally concise, and broadly applicable strategy for directly visualizing RNA base pairs and dynamics in cells.

2019 ◽  
Author(s):  
Anthony M. Mustoe ◽  
Nicole Lama ◽  
Patrick S. Irving ◽  
Samuel W. Olson ◽  
Kevin M. Weeks

ABSTRACTRNA structure and dynamics are critical to biological function. However, strategies for determining RNA structure in vivo are limited, with established chemical probing and newer duplex detection methods each having notable deficiencies. Here we convert the common reagent dimethyl sulfate (DMS) into a useful probe of all four RNA nucleotides. Building on this advance, we introduce PAIR-MaP, which uses single-molecule correlated chemical probing to directly detect base pairing interactions in cells. PAIR-MaP has superior resolution and accuracy compared to alternative experiments, can resolve alternative pairing interactions of structurally dynamic RNAs, and enables highly accurate structure modeling, including of RNAs containing multiple pseudoknots and extensively bound by proteins. Application of PAIR-MaP to human RNase MRP and two bacterial mRNA 5'-UTRs reveals new functionally important and complex structures undetectable by conventional analyses. PAIR-MaP is a powerful, experimentally concise, and broadly applicable strategy for directly visualizing RNA base pairs and dynamics in cells.


2017 ◽  
Author(s):  
Eva Maria Novoa ◽  
Jean-Denis Beaudoin ◽  
Antonio J Giraldez ◽  
John S Mattick ◽  
Manolis Kellis

ABSTRACTGenome-wide RNA structure maps have recently become available through the coupling of in vivo chemical probing reagents with next-generation sequencing. Initial analyses relied on the identification of truncated reverse transcription reads to identify the chemically modified nucleotides, but recent studies have shown that mutational signatures can also be used. While these two methods have been employed interchangeably, here we show that they actually provide complementary information. Consequently, analyses using exclusively one of the two methodologies may disregard a significant portion of the structural information. We also show that the identity and sequence environment of the modified nucleotide greatly affect the odds of introducing a mismatch or causing reverse transcriptase drop-off. Finally, we identify specific mismatch signatures generated by dimethyl sulfate probing that can be exploited to remove false positives typically produced in RNA structurome analyses, and how these signatures vary depending on the reverse transcription enzyme used.


2000 ◽  
Vol 20 (13) ◽  
pp. 4522-4531 ◽  
Author(s):  
Xavier Darzacq ◽  
Tamás Kiss

ABSTRACT The C and D box-containing (box C/D) small nucleolar RNAs (snoRNAs) function in the nucleolytic processing and 2′-O-methylation of precursor rRNA. In vertebrates, most box C/D snoRNAs are processed from debranched pre-mRNA introns by exonucleolytic activities. Elements directing accurate snoRNA excision are located within the snoRNA itself; they comprise the conserved C and D boxes and an adjoining 5′,3′-terminal stem. Although the terminal stem has been demonstrated to be essential for snoRNA accumulation, many snoRNAs lack a terminal helix. To identify thecis-acting elements supporting the accumulation of intron-encoded box C/D snoRNAs devoid of a terminal stem, we have investigated the in vivo processing of the human U46 snoRNA and an artificial snoRNA from the human β-globin pre-mRNA. We demonstrate that internal and/or external stem structures located within the snoRNA or in the intronic flanking sequences support the accumulation of mammalian box C/D snoRNAs lacking a canonical terminal stem. In the intronic precursor RNA, transiently formed external and/or stable internal base-pairing interactions fold the C and D boxes together and therefore facilitate the binding of snoRNP proteins. Since the external intronic stems are degraded during snoRNA processing, we propose that the C and D boxes alone can provide metabolic stability for the mature snoRNA.


2018 ◽  
Vol 115 (48) ◽  
pp. 12170-12175 ◽  
Author(s):  
Zhao Su ◽  
Yin Tang ◽  
Laura E. Ritchey ◽  
David C. Tack ◽  
Mengmeng Zhu ◽  
...  

The heat shock response is crucial for organism survival in natural environments. RNA structure is known to influence numerous processes related to gene expression, but there have been few studies on the global RNA structurome as it prevails in vivo. Moreover, how heat shock rapidly affects RNA structure genome-wide in living systems remains unknown. We report here in vivo heat-regulated RNA structuromes. We applied Structure-seq chemical [dimethyl sulfate (DMS)] structure probing to rice (Oryza sativa L.) seedlings with and without 10 min of 42 °C heat shock and obtained structural data on >14,000 mRNAs. We show that RNA secondary structure broadly regulates gene expression in response to heat shock in this essential crop species. Our results indicate significant heat-induced elevation of DMS reactivity in the global transcriptome, revealing RNA unfolding over this biological temperature range. Our parallel Ribo-seq analysis provides no evidence for a correlation between RNA unfolding and heat-induced changes in translation, in contrast to the paradigm established in prokaryotes, wherein melting of RNA thermometers promotes translation. Instead, we find that heat-induced DMS reactivity increases correlate with significant decreases in transcript abundance, as quantified from an RNA-seq time course, indicating that mRNA unfolding promotes transcript degradation. The mechanistic basis for this outcome appears to be mRNA unfolding at both 5′ and 3′-UTRs that facilitates access to the RNA degradation machinery. Our results thus reveal unexpected paradigms governing RNA structural changes and the eukaryotic RNA life cycle.


2019 ◽  
Vol 12 (05) ◽  
pp. 1930010 ◽  
Author(s):  
Shiqi Wang ◽  
Binglin Shen ◽  
Sheng Ren ◽  
Yihua Zhao ◽  
Silu Zhang ◽  
...  

With the development of the new detection methods and the function of fluorescent molecule, researchers hope to further explore the internal mechanisms of organisms, monitor changes in the intracellular microenvironment, and dynamic processes of molecular interactions in cells. Fluorescence resonance energy transfer (FRET) describes the energy transfer process between donor fluorescent molecules and acceptor fluorescent molecules. It is an important means to detect protein–protein interactions and protein conformation changes in cells. Fluorescence lifetime imaging microscopy (FLIM) enables noninvasive measurement of the fluorescence lifetime of fluorescent particles in vivo. The FRET–FLIM technology, which is use FLIM to quantify and analyze FRET, enables real-time monitoring of dynamic changes of proteins in biological cells and analysis of protein interaction mechanisms. The distance between donor and acceptor and their respective fluorescent lifetime, which are of great importance for studying the mechanism of intracellular activity can be obtained by data analysis and algorithm fitting.


2020 ◽  
Vol 6 (1) ◽  
pp. eaax6969 ◽  
Author(s):  
Junhong Choi ◽  
Sinéad O’Loughlin ◽  
John F. Atkins ◽  
Joseph D. Puglisi

Maintenance of translational reading frame ensures the fidelity of information transfer during protein synthesis. Yet, programmed ribosomal frameshifting sequences within the coding region promote a high rate of reading frame change at predetermined sites thus enriching genomic information density. Frameshifting is typically stimulated by the presence of 3′ messenger RNA (mRNA) structures, but how these mRNA structures enhance −1 frameshifting remains debatable. Here, we apply single-molecule and ensemble approaches to formulate a mechanistic model of ribosomal −1 frameshifting. Our model suggests that the ribosome is intrinsically susceptible to frameshift before its translocation and this transient state is prolonged by the presence of a precisely positioned downstream mRNA structure. We challenged this model using temperature variation in vivo, which followed the prediction made based on in vitro results. Our results provide a quantitative framework for analyzing other frameshifting enhancers and a potential approach to control gene expression dynamically using programmed frameshifting.


2019 ◽  
Vol 77 (16) ◽  
pp. 3231-3244 ◽  
Author(s):  
Maria Pokornowska ◽  
Marek C. Milewski ◽  
Kinga Ciechanowska ◽  
Agnieszka Szczepańska ◽  
Marta Wojnicka ◽  
...  

Abstract The ribonuclease Dicer produces microRNAs (miRNAs) and small interfering RNAs that are handed over to Ago proteins to control gene expression by targeting complementary sequences within transcripts. Interestingly, a growing number of reports have demonstrated that the activity of Dicer may extend beyond the biogenesis of small regulatory RNAs. Among them, a report from our latest studies revealed that human Dicer facilitates base pairing of complementary sequences present in two nucleic acids, thus acting as a nucleic acid annealer. Accordingly, in this manuscript, we address how RNA structure influences the annealing activity of human Dicer. We show that Dicer supports hybridization between a small RNA and a complementary sequence of a longer RNA in vitro, even when both complementary sequences are trapped within secondary structures. Moreover, we show that under applied conditions, human Ago2, a core component of RNA-induced silencing complex, displays very limited annealing activity. Based on the available data from new-generation sequencing experiments regarding the RNA pool bound to Dicer in vivo, we show that multiple Dicer-binding sites within mRNAs also contain miRNA targets. Subsequently, we demonstrate in vitro that Dicer but not Ago2 can anneal miRNA to its target present within mRNA. We hypothesize that not all miRNA duplexes are handed over to Ago proteins. Instead, miRNA-Dicer complexes could target specific sequences within transcripts and either compete or cooperate for binding sites with miRNA-Ago complexes. Thus, not only Ago but also Dicer might be directly involved in the posttranscriptional control of gene expression.


Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2252
Author(s):  
Jennifer S. H. Im ◽  
Laura R. Newburn ◽  
Gregory Kent ◽  
K. Andrew White

Many positive-sense RNA viruses transcribe subgenomic (sg) mRNAs during infections that template the translation of a subset of viral proteins. Red clover necrotic mosaic virus (RCNMV) expresses its capsid protein through the transcription of a sg mRNA from RNA1 genome segment. This transcription event is activated by an RNA structure formed by base pairing between a trans-activator (TA) in RNA2 and a trans-activator binding site (TABS) in RNA1. In this study, the impact of the structural context of the TABS in RNA1 on the TA–TABS interaction and sg mRNA transcription was investigated using in vitro and in vivo approaches. The results (i) generated RNA secondary structure models for the TA and TABS, (ii) revealed that the TABS is partially base paired with proximal upstream sequences, which limits TA access, (iii) demonstrated that the aforementioned intra-RNA1 base pairing involving the TABS modulates the TA–TABS interaction in vitro and sg mRNA levels during infections, and (iv) revealed that the TABS in RNA1 can be modified to mediate sg mRNA transcription in a TA-independent manner. These findings advance our understanding of transcriptional regulation in RCNMV and provide novel insights into the origin of the TA–TABS interaction.


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