scholarly journals Light-Dependent Translation Change of Arabidopsis psbA Correlates with RNA Structure Alterations at the Translation Initiation Region

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 322
Author(s):  
Piotr Gawroński ◽  
Christel Enroth ◽  
Peter Kindgren ◽  
Sebastian Marquardt ◽  
Stanisław Karpiński ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Translation Initiation ◽  
Rna Structure ◽  
Regulatory Protein ◽  
High Light ◽  
Ribosome Profiling ◽  
General Mechanism ◽  
Mrna Secondary Structure ◽  
Translation Initiation Region

mRNA secondary structure influences translation. Proteins that modulate the mRNA secondary structure around the translation initiation region may regulate translation in plastids. To test this hypothesis, we exposed Arabidopsis thaliana to high light, which induces translation of psbA mRNA encoding the D1 subunit of photosystem II. We assayed translation by ribosome profiling and applied two complementary methods to analyze in vivo RNA secondary structure: DMS-MaPseq and SHAPE-seq. We detected increased accessibility of the translation initiation region of psbA after high light treatment, likely contributing to the observed increase in translation by facilitating translation initiation. Furthermore, we identified the footprint of a putative regulatory protein in the 5′ UTR of psbA at a position where occlusion of the nucleotide sequence would cause the structure of the translation initiation region to open up, thereby facilitating ribosome access. Moreover, we show that other plastid genes with weak Shine-Dalgarno sequences (SD) are likely to exhibit psbA-like regulation, while those with strong SDs do not. This supports the idea that changes in mRNA secondary structure might represent a general mechanism for translational regulation of psbA and other plastid genes.

scholarly journals Light-dependent translation change of Arabidopsis psbA correlates with RNA structure alterations at the translation initiation region

2020 ◽  
Author(s):  
Piotr Gawroński ◽  
Christel Enroth ◽  
Peter Kindgren ◽  
Sebastian Marquardt ◽  
Stanisław Karpiński ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Translation Initiation ◽  
Rna Structure ◽  
Regulatory Protein ◽  
High Light ◽  
Ribosome Profiling ◽  
General Mechanism ◽  
Mrna Secondary Structure ◽  
Translation Initiation Region

SUMMARYmRNA secondary structure influences translation. Proteins that modulate the mRNA secondary structure around the translation initiation region may regulate translation in plastids. To test this hypothesis, we exposed Arabidopsis thaliana to high light, which induces translation of psbA mRNA encoding the D1 subunit of photosystem II. We assayed translation by ribosome profiling and applied two complementary methods to analyze in vivo RNA secondary structure: DMS-MaPseq and SHAPE-seq. We detected increased accessibility of the translation initiation region of psbA after high light treatment, likely contributing to the observed increase in translation by facilitating translation initiation. Furthermore, we identified the footprint of a putative regulatory protein in the 5’ UTR of psbA at a position where occlusion of the nucleotide sequence would cause the structure of the translation initiation region to open up, thereby facilitating ribosome access. Moreover, we show that other plastid genes with weak Shine-Dalgarno sequences (SD) are likely to exhibit psbA-like regulation, while those with strong SDs do not. This supports the idea that changes in mRNA secondary structure might represent a general mechanism for translational regulation of psbA and other plastid genes.SIGNIFICANCERNA structure changes in the translation initiation region, most likely as a result of protein binding, affect the translation of psbA and possibly other plastid genes with weak Shine-Dalgarno sequences.

scholarly journals Repurposing Ribo-Seq to provide insights into structured RNAs

2020 ◽  
Author(s):  
Brayon J. Fremin ◽  
Ami S. Bhatt
Keyword(s):  
Secondary Structure ◽  
Rna Structure ◽  
Large Scale ◽  
Structural Information ◽  
Ribosome Profiling ◽  
Rna Structures ◽  
Size Selection ◽  
Bacterial Ribosome ◽  
Powerful Approach

AbstractRibosome profiling (Ribo-Seq) is a powerful method to study translation in bacteria. However, this method can enrich RNAs that are not bound by ribosomes, but rather, are protected from degradation in another way. For example, Escherichia coli Ribo-Seq libraries also capture reads from most non-coding RNAs (ncRNAs). These fragments of ncRNAs pass all size selection steps of the Ribo-Seq protocol and survive hours of MNase treatment, presumably without protection from the ribosome or other macromolecules or proteins. Since bacterial ribosome profiling does not directly isolate ribosomes, but instead uses broad size range cutoffs to fractionate actively translated RNAs, it is understandable that some ncRNAs are retained after size selection. However, how these ‘contaminants’ survive MNase treatment is unclear. Through analyzing metaRibo-Seq reads across ssrS, a well established structured RNA in E. coli, and structured direct repeats from Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) arrays in Ruminococcus lactaris, we observed that these RNAs are protected from MNase treatment by virtue of their secondary structure. Therefore, large volumes of data previously discarded as contaminants in bacterial Ribo-Seq experiments can, in fact, be used to gain information regarding the in vivo secondary structure of ncRNAs, providing unique insight into their native functional structures.ImportanceWe observe that ‘contaminant’ signals in bacterial Ribo-Seq experiments that are often disregarded and discarded, in fact, strongly overlap with structured regions of ncRNAs. Structured ncRNAs are pivotal mediators of bioregulation in bacteria and their functions are often reliant on their specific structures. We present an approach to access important RNA structural information through merely repurposing ‘contaminant’ signals in bacterial Ribo-Seq experiments. This powerful approach enables us to partially resolve RNA structures, identify novel structured RNAs, and elucidate RNA structure-function relationships in bacteria at a large-scale and in vivo.

scholarly journals Heat-Induced Synthesis of ς32 inEscherichia coli: Structural and Functional Dissection ofrpoH mRNA Secondary Structure

1999 ◽  
Vol 181 (2) ◽  
pp. 401-410 ◽  
Author(s):  
Miyo Morita ◽  
Masaaki Kanemori ◽  
Hideki Yanagi ◽  
Takashi Yura
Keyword(s):  
Heat Shock ◽  
Secondary Structure ◽  
Secondary Structures ◽  
Mrna Secondary Structure ◽  
Translation Initiation Region ◽  
Stem Loop ◽  
Structure Probing ◽  
Downstream Box ◽  
Temperature Upshift

ABSTRACT The heat shock response in Escherichia coli depends primarily on the increased synthesis and stabilization of otherwise scarce and unstable ς32 (rpoH gene product), which is required for the transcription of heat shock genes. The heat-induced synthesis of ς32 occurs at the level of translation, and genetic evidence has suggested the involvement of a secondary structure at the 5′ portion (nucleotides −19 to +247) ofrpoH mRNA in regulation. We now present evidence for the mRNA secondary structure model by means of structure probing of RNA with chemical and enzymatic probes. A similar analysis of several mutant RNAs with a mutation predicted to alter a base pairing or with two compensatory mutations revealed altered secondary structures consistent with the expression and heat inducibility of the corresponding fusion constructs observed in vivo. These findings led us to assess the possible roles of each of the stem-loop structures by analyzing an additional set of deletions and base substitutions. The results indicated not only the primary importance of base pairings between the translation initiation region of ca. 20 nucleotides (the AUG initiation codon plus the “downstream box”) and the internal region of rpoH mRNA but also the requirement of appropriate stability of mRNA secondary structures for characteristic thermoregulation, i.e., repression at a low temperature and induction upon a temperature upshift.

scholarly journals A Sequence-Independent, Unstructured Internal Ribosome Entry Site Is Responsible for Internal Expression of the Coat Protein of Turnip Crinkle Virus

2017 ◽  
Vol 91 (8) ◽  
Author(s):  
Jared May ◽  
Philip Johnson ◽  
Huma Saleem ◽  
Anne E. Simon
Keyword(s):  
Secondary Structure ◽  
Coat Protein ◽  
Translation Initiation ◽  
Rna Structure ◽  
Turnip Crinkle Virus ◽  
Internal Ribosome Entry ◽  
Content Type ◽  
Low Levels

ABSTRACT To maximize the coding potential of viral genomes, internal ribosome entry sites (IRES) can be used to bypass the traditional requirement of a 5′ cap and some/all of the associated translation initiation factors. Although viral IRES typically contain higher-order RNA structure, an unstructured sequence of about 84 nucleotides (nt) immediately upstream of the Turnip crinkle virus (TCV) coat protein (CP) open reading frame (ORF) has been found to promote internal expression of the CP from the genomic RNA (gRNA) both in vitro and in vivo. An absence of extensive RNA structure was predicted using RNA folding algorithms and confirmed by selective 2′-hydroxyl acylation analyzed by primer extension (SHAPE) RNA structure probing. Analysis of the IRES region in vitro by use of both the TCV gRNA and reporter constructs did not reveal any sequence-specific elements but rather suggested that an overall lack of structure was an important feature for IRES activity. The CP IRES is A-rich, independent of orientation, and strongly conserved among viruses in the same genus. The IRES was dependent on eIF4G, but not eIF4E, for activity. Low levels of CP accumulated in vivo in the absence of detectable TCV subgenomic RNAs, strongly suggesting that the IRES was active in the gRNA in vivo. Since the TCV CP also serves as the viral silencing suppressor, early translation of the CP from the viral gRNA is likely important for countering host defenses. Cellular mRNA IRES also lack extensive RNA structures or sequence conservation, suggesting that this viral IRES and cellular IRES may have similar strategies for internal translation initiation. IMPORTANCE Cap-independent translation is a common strategy among positive-sense, single-stranded RNA viruses for bypassing the host cell requirement of a 5′ cap structure. Viral IRES, in general, contain extensive secondary structure that is critical for activity. In contrast, we demonstrate that a region of viral RNA devoid of extensive secondary structure has IRES activity and produces low levels of viral coat protein in vitro and in vivo. Our findings may be applicable to cellular mRNA IRES that also have little or no sequences/structures in common.

scholarly journals Secondary Structure of Chloroplast mRNAs In Vivo and In Vitro

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 323
Author(s):  
Piotr Gawroński ◽  
Aleksandra Pałac ◽  
Lars B. Scharff
Keyword(s):  
Gene Expression ◽  
Secondary Structure ◽  
Translation Initiation ◽  
Structural Information ◽  
Regulation Of Gene Expression ◽  
Dimethyl Sulfate ◽  
Translation Efficiency ◽  
Mrna Secondary Structure

mRNA secondary structure can influence gene expression, e.g., by influencing translation initiation. The probing of in vivo mRNA secondary structures is therefore necessary to understand what determines the efficiency and regulation of gene expression. Here, in vivo mRNA secondary structure was analyzed using dimethyl sulfate (DMS)-MaPseq and compared to in vitro-folded RNA. We used an approach to analyze specific, full-length transcripts. To test this approach, we chose low, medium, and high abundant mRNAs. We included both monocistronic and multicistronic transcripts. Because of the slightly alkaline pH of the chloroplast stroma, we could probe all four nucleotides with DMS. The structural information gained was evaluated using the known structure of the plastid 16S rRNA. This demonstrated that the results obtained for adenosines and cytidines were more reliable than for guanosines and uridines. The majority of mRNAs analyzed were less structured in vivo than in vitro. The in vivo secondary structure of the translation initiation region of most tested genes appears to be optimized for high translation efficiency.

scholarly journals Hypertrophic cardiomyopathy MYH7 mutation R723G alters mRNA secondary structure

2020 ◽  
Vol 52 (1) ◽  
pp. 15-19
Author(s):  
J. Rose ◽  
T. Kraft ◽  
B. Brenner ◽  
J. Montag
Keyword(s):  
Hypertrophic Cardiomyopathy ◽  
Secondary Structure ◽  
Experimental Evidence ◽  
Point Mutation ◽  
Shape Analysis ◽  
Allelic Imbalance ◽  
Mrna Secondary Structure ◽  
Wild Type ◽  
Mrna Structure

Point mutation R723G in the MYH7 gene causes hypertrophic cardiomyopathy (HCM). Heterozygous patients with this mutation exhibit a comparable allelic imbalance of the MYH7 gene. On average 67% of the total MYH7 mRNA are derived from the MYH7R723G-allele and 33% from the MYH7WT allele. Mechanisms underlying mRNA allelic imbalance are largely unknown. We suggest that a different mRNA lifetime of the alleles may cause the allelic drift in R723G patients. A potent regulator of mRNA lifetime is its secondary structure. To test for alterations in the MYH7R723G mRNA structure we used selective 2′-hydroxyl acylation analyzed by primer extension (SHAPE) analysis. We show significantly different SHAPE reactivity of wild-type and MYH7R723G RNA, which is in accordance with bioinformatically predicted structures. Thus, we provide the first experimental evidence for mRNA secondary structure alterations by the HCM point mutation. We assume that this may result in a prolonged lifetime of MYH7R723G mRNA in vivo and subsequently in the determined allelic imbalance.

scholarly journals Fidelity of translation initiation is required for coordinated respiratory complex assembly

2019 ◽  
Vol 5 (12) ◽  
pp. eaay2118 ◽  
Author(s):  
Danielle L. Rudler ◽  
Laetitia A. Hughes ◽  
Kara L. Perks ◽  
Tara R. Richman ◽  
Irina Kuznetsova ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Mitochondrial Protein ◽  
Molecular Machines ◽  
Ribosome Profiling ◽  
Untranslated Regions ◽  
Mitochondrial Protein Synthesis ◽  
Mitochondrial Translation ◽  
Initiation Factors ◽  
Mitochondrial Ribosomes

Mammalian mitochondrial ribosomes are unique molecular machines that translate 11 leaderless mRNAs; however, it is not clear how mitoribosomes initiate translation, since mitochondrial mRNAs lack untranslated regions. Mitochondrial translation initiation shares similarities with prokaryotes, such as the formation of a ternary complex of fMet-tRNAMet, mRNA and the 28S subunit, but differs in the requirements for initiation factors. Mitochondria have two initiation factors: MTIF2, which closes the decoding center and stabilizes the binding of the fMet-tRNAMet to the leaderless mRNAs, and MTIF3, whose role is not clear. We show that MTIF3 is essential for survival and that heart- and skeletal muscle–specific loss of MTIF3 causes cardiomyopathy. We identify increased but uncoordinated mitochondrial protein synthesis in mice lacking MTIF3, resulting in loss of specific respiratory complexes. Ribosome profiling shows that MTIF3 is required for recognition and regulation of translation initiation of mitochondrial mRNAs and for coordinated assembly of OXPHOS complexes in vivo.

scholarly journals Structured RNA Contaminants in Bacterial Ribo-Seq

mSphere ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Brayon J. Fremin ◽  
Ami S. Bhatt
Keyword(s):  
Rna Structure ◽  
Large Scale ◽  
Partial Information ◽  
Ribosome Profiling ◽  
Micrococcal Nuclease ◽  
Data Sets ◽  
Rna Structures ◽  
Content Type ◽  
Sequencing Library

ABSTRACT Ribosome profiling (Ribo-Seq) is a powerful method to study translation in bacteria. However, Ribo-Seq signal can be observed across RNAs that one would not expect to be bound by ribosomes. For example, Escherichia coli Ribo-Seq libraries also capture reads from most noncoding RNAs (ncRNAs). While some of these ncRNAs may overlap coding regions, this alone does not explain the majority of observed signal across ncRNAs. These fragments of ncRNAs in Ribo-Seq data pass all size selection steps of the Ribo-Seq protocol and survive hours of micrococcal nuclease (MNase) treatment. In this work, we specifically focus on Ribo-Seq signal across ncRNAs and provide evidence to suggest that RNA structure, as opposed to ribosome binding, protects them from degradation and allows them to persist in the Ribo-Seq sequencing library preparation. By inspecting these “contaminant reads” in bacterial Ribo-Seq, we show that data previously disregarded in bacterial Ribo-Seq experiments may, in fact, be used to gain partial information regarding the in vivo secondary structure of ncRNAs. IMPORTANCE Structured ncRNAs are pivotal mediators of bioregulation in bacteria, and their functions are often reliant on their specific structures. Here, we first inspect Ribo-Seq reads across noncoding regions, identifying contaminant reads in these libraries. We observe that contaminant reads in bacterial Ribo-Seq experiments that are often disregarded, in fact, strongly overlap with structured regions of ncRNAs. We then perform several bioinformatic analyses to determine why these contaminant reads may persist in Ribo-Seq libraries. Finally, we highlight some structured RNA contaminants in Ribo-Seq and support the hypothesis that structures in the RNA protect them from MNase digestion. We conclude that researchers should be cautious when interpreting Ribo-Seq signal as coding without considering signal distribution. These findings also may enable us to partially resolve RNA structures, identify novel structured RNAs, and elucidate RNA structure-function relationships in bacteria at a large scale and in vivo through the reanalysis of existing Ribo-Seq data sets.

The involvement of mRNA secondary structure in protein synthesis

1987 ◽  
Vol 65 (6) ◽  
pp. 576-581 ◽  
Author(s):  
Jerry Pelletier ◽  
Nahum Sonenberg
Keyword(s):  
Secondary Structure ◽  
Translation Initiation ◽  
Binding Proteins ◽  
Atp Hydrolysis ◽  
Mrna Translation ◽  
Noncoding Region ◽  
Translational Efficiency ◽  
Mrna Secondary Structure ◽  
Complex Process ◽  
Eukaryotic Mrnas

Translation initiation in eukaryotes is a complex process involving many factors. A key step in this process is the binding of mRNA to the 43S preinitiation complex. This is generally the rate-limiting step in translation initiation and consequently a major determinant of mRNA translational efficiency. The primary and secondary structure of the mRNA 5′ noncoding region have been implicated in modulating translational efficiency. Translational efficiency was shown to be inversely proportional to the degree of secondary structure at the mRNA 5′ noncoding region. Furthermore, it was shown that cap-binding proteins that interact with the 5′ cap structure (m7GpppN) of eukaryotic mRNAs are involved in the "unwinding" of the mRNA secondary structure, in an ATP hydrolysis mediated event, to facilitate ribosome binding. Thus, cap-binding proteins can potentially regulate mRNA translation. Here, we discuss the available data supporting the notion that eukaryotic 5′ mRNA secondary structure plays an important role in translation initiation and the possible regulation of this process.

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