scholarly journals A Ribosome Interaction Surface Sensitive to mRNA GCN Periodicity

Biomolecules ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 849 ◽  
Author(s):  
Kristen Scopino ◽  
Elliot Williams ◽  
Abdelrahman Elsayed ◽  
William A. Barr ◽  
Daniel Krizanc ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Protein Translation ◽  
Open Reading Frames ◽  
Base Stacking ◽  
Codon Positions ◽  
Guanidinium Group ◽  
Dynamics Simulations ◽  
A Site ◽  
Interaction Surface ◽  
Reading Frames

A longstanding challenge is to understand how ribosomes parse mRNA open reading frames (ORFs). Significantly, GCN codons are over-represented in the initial codons of ORFs of prokaryote and eukaryote mRNAs. We describe a ribosome rRNA-protein surface that interacts with an mRNA GCN codon when next in line for the ribosome A-site. The interaction surface is comprised of the edges of two stacked rRNA bases: the Watson–Crick edge of 16S/18S rRNA C1054 and the adjacent Hoogsteen edge of A1196 (Escherichia coli 16S rRNA numbering). Also part of the interaction surface, the planar guanidinium group of a conserved Arginine (R146 of yeast ribosomal protein Rps3) is stacked adjacent to A1196. On its other side, the interaction surface is anchored to the ribosome A-site through base stacking of C1054 with the wobble anticodon base of the A-site tRNA. Using molecular dynamics simulations of a 495-residue subsystem of translocating ribosomes, we observed base pairing of C1054 to nucleotide G at position 1 of the next-in-line codon, consistent with previous cryo-EM observations, and hydrogen bonding of A1196 and R146 to C at position 2. Hydrogen bonding to both of these codon positions is significantly weakened when C at position 2 is changed to G, A or U. These sequence-sensitive mRNA-ribosome interactions at the C1054-A1196-R146 (CAR) surface potentially contribute to the GCN-mediated regulation of protein translation.

scholarly journals A Ribosome Interaction Surface Sensitive to mRNA GCN Periodicity

2020 ◽  
Author(s):  
Kristen Scopino ◽  
Elliot Williams ◽  
Abdelrahman Elsayed ◽  
William A. Barr ◽  
Daniel Krizanc ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Hydrogen Bonding ◽  
18S Rrna ◽  
Protein Translation ◽  
Base Stacking ◽  
Codon Positions ◽  
Guanidinium Group ◽  
Dynamics Simulations ◽  
A Site ◽  
Interaction Surface

ABSTRACTGCN codons are over-represented in initial codons of ORFs of prokaryote and eukaryote mRNAs. We describe a ribosome rRNA-protein surface that interacts with an mRNA GCN codon when next-in-line for the ribosome A site. The interaction surface is comprised of the edges of two stacked rRNA bases: the Watson-Crick edge of 16S/18S rRNA C1054 and adjacent Hoogsteen edge of A1196 (Escherichia coli 16S rRNA numbering). Also part of the interaction surface, the planar guanidinium group of a conserved Arginine (R146 of yeast ribosomal protein Rps3) is stacked adjacent to A1196. On its other side, the interaction surface is anchored to the ribosome A site through base stacking of C1054 with the wobble anticodon base of the A-site tRNA. Using Molecular Dynamics simulations of a 495-residue subsystem of translocating ribosomes, we observe base pairing of C1054 to nucleotide G at position 1 of the next-in-line codon, consistent with previous cryo-EM observations, and hydrogen bonding of A1196 and R146 to C at position 2. Hydrogen bonding to both of these codon positions is significantly weakened when C at position 2 is changed to G, A or U. These sequence-sensitive mRNA-ribosome interactions at the C1054-A1196-R146 (CAR) surface potentially contribute to GCN-mediated regulation of protein translation.

scholarly journals GCN sensitive protein translation in yeast

2020 ◽  
Author(s):  
William A. Barr ◽  
Ruchi B. Sheth ◽  
Jack Kwon ◽  
Jungwoo Cho ◽  
Jacob W. Glickman ◽  
...  
Keyword(s):  
Large Scale ◽  
Protein Translation ◽  
Open Reading Frames ◽  
Translation Efficiency ◽  
E Coli ◽  
Positive Effects ◽  
Braking System ◽  
Expression Studies ◽  
A Site ◽  
Interaction Surface

AbstractLevels of protein translation by ribosomes are governed both by features of the translation machinery as well as sequence properties of the mRNAs themselves. We focus here on a striking three-nucleotide periodicity, characterized by overrepresentation of GCN codons and underrepresentation of G at the second position of codons, that is observed in Open Reading Frames (ORFs) of mRNAs. Our examination of mRNA sequences in Saccharomyces cerevisiae revealed that this periodicity is particularly pronounced in the initial codons--the ramp region--of ORFs of genes with high protein expression. It is also found in mRNA sequences immediately following non-standard AUG start sites, located upstream or downstream of the standard annotated start sites of genes. To explore the possible influences of the ramp GCN periodicity on translation efficiency, we tested edited ramps with accentuated or depressed periodicity in two test genes, SKN7 and HMT1. Greater conformance to (GCN)n was found to significantly depress translation, whereas disrupting conformance had neutral or positive effects on translation. Our recent Molecular Dynamics analysis of a subsystem of translocating ribosomes in yeast revealed an interaction surface that H-bonds to the +1 codon that is about to enter the ribosome decoding center A site. The surface, comprised of 16S/18S rRNA C1054 and A1196 (E. coli numbering) and R146 of ribosomal protein Rps3, preferentially interacts with GCN codons, and we hypothesize that modulation of this mRNA-ribosome interaction may underlie GCN-mediated regulation of protein translation. Integration of our expression studies with large-scale reporter studies of ramp sequence variants suggests a model in which the C1054-A1196-R146 (CAR) interaction surface can act as both an accelerator and braking system for ribosome translation.

scholarly journals Arginine Methylation Regulates Ribosome CAR Function

2021 ◽  
Vol 22 (3) ◽  
pp. 1335
Author(s):  
Kristen Scopino ◽  
Carol Dalgarno ◽  
Clara Nachmanoff ◽  
Daniel Krizanc ◽  
Kelly M. Thayer ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Arginine Methylation ◽  
Translation Regulation ◽  
E Coli ◽  
Pi Stacking ◽  
Cellular Context ◽  
Guanidinium Group ◽  
Stressed Cells ◽  
A Site ◽  
Interaction Surface

The ribosome CAR interaction surface is hypothesized to provide a layer of translation regulation through hydrogen-bonding to the +1 mRNA codon that is next to enter the ribosome A site during translocation. The CAR surface consists of three residues, 16S/18S rRNA C1054, A1196 (E. coli 16S numbering), and R146 of yeast ribosomal protein Rps3. R146 can be methylated by the Sfm1 methyltransferase which is downregulated in stressed cells. Through molecular dynamics analysis, we show here that methylation of R146 compromises the integrity of CAR by reducing the cation-pi stacking of the R146 guanidinium group with A1196, leading to reduced CAR hydrogen-bonding with the +1 codon. We propose that ribosomes assembled under stressed conditions have unmethylated R146, resulting in elevated CAR/+1 codon interactions, which tunes translation levels in response to the altered cellular context.

scholarly journals Arginine Methylation Regulates Ribosome CAR Function

2020 ◽  
Author(s):  
Kristen Scopino ◽  
Carol Dalgarno ◽  
Clara Nachmanoff ◽  
Daniel Krizanc ◽  
Kelly M. Thayer ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Arginine Methylation ◽  
Translation Regulation ◽  
E Coli ◽  
Pi Stacking ◽  
Cellular Context ◽  
Guanidinium Group ◽  
Stressed Cells ◽  
A Site ◽  
Interaction Surface

AbstractThe ribosome CAR interaction surface is hypothesized to provide a layer of translation regulation through hydrogen-bonding to the +1 mRNA codon that is next to enter the ribosome A site during translocation. The CAR surface consists of three residues, 16S/18S rRNA C1054, A1196 (E. coli 16S numbering), and R146 of yeast ribosomal protein Rps3. R146 can be methylated by the Sfm1 methyltransferase which is downregulated in stressed cells. Through molecular dynamics analysis, we show here that methylation of R146 compromises the integrity of CAR by reducing the pi stacking of the R146 guanidinium group with A1196, leading to reduced CAR hydrogen-bonding with the +1 codon. We propose that ribosomes assembled under stressed conditions have unmethylated R146, resulting in elevated CAR/+1 codon interactions, which tunes translation levels in response to the altered cellular context.

scholarly journals Engineering ribosomal leaky scanning and upstream open reading frames for precise control of protein translation

Bioengineered ◽  
2014 ◽  
Vol 5 (3) ◽  
pp. 186-192 ◽  
Author(s):  
Joshua P Ferreira ◽  
William L Noderer ◽  
Alexander J Diaz de Arce ◽  
Clifford L Wang
Keyword(s):  
Protein Translation ◽  
Open Reading Frames ◽  
Leaky Scanning ◽  
Precise Control ◽  
Upstream Open Reading Frames ◽  
Reading Frames

scholarly journals TBIO-26. NON-CANONICAL OPEN READING FRAMES ENCODE FUNCTIONAL PROTEINS ESSENTIAL FOR CANCER CELL SURVIVAL

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii471-iii471
Author(s):  
John Prensner ◽  
Oana Enache ◽  
Victor Luria ◽  
Karsten Krug ◽  
Karl Clauser ◽  
...  
Keyword(s):  
Cell Lines ◽  
Cancer Cell ◽  
Protein Translation ◽  
Cancer Cell Lines ◽  
Open Reading Frames ◽  
Sequencing Analysis ◽  
Multiple Cancer ◽  
Cancer Types ◽  
Non Coding Rnas ◽  
Reading Frames

Abstract The brain is the foremost non-gonadal tissue for expression of non-coding RNAs of unclear function. Yet, whether such transcripts are truly non-coding or rather the source of non-canonical protein translation is unknown. Here, we used functional genomic screens to establish the cellular bioactivity of non-canonical proteins located in putative non-coding RNAs or untranslated regions of protein-coding genes. We experimentally interrogated 553 open reading frames (ORFs) identified by ribosome profiling for three major phenotypes: 257 (46%) demonstrated protein translation when ectopically expressed in HEK293T cells, 401 (73%) induced gene expression changes following ectopic expression across 4 cancer cell types, and 57 (10%) induced a viability defect when the endogenous ORF was knocked out using CRISPR/Cas9 in 8 human cancer cell lines. CRISPR tiling and start codon mutagenesis indicated that the biological impact of these non-canonical ORFs required their translation as opposed to RNA-mediated effects. We functionally characterized one of these ORFs, G029442—renamed GREP1 (Glycine-Rich Extracellular Protein-1)—as a cancer-implicated gene with high expression in multiple cancer types, such as gliomas. GREP1 knockout in >200 cancer cell lines reduced cell viability in multiple cancer types, including glioblastoma, in a cell-autonomous manner and produced cell cycle arrest via single-cell RNA sequencing. Analysis of the secretome of GREP1-expressing cells showed increased abundance of the oncogenic cytokine GDF15, and GDF15 supplementation mitigated the growth inhibitory effect of GREP1 knock-out. Taken together, these experiments suggest that the non-canonical ORFeome is surprisingly rich in biologically active proteins and potential cancer therapeutic targets deserving of further study.

scholarly journals Non-canonical open reading frames encode functional proteins essential for cancer cell survival

2020 ◽  
Author(s):  
John R. Prensner ◽  
Oana M. Enache ◽  
Victor Luria ◽  
Karsten Krug ◽  
Karl R. Clauser ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Lines ◽  
Cancer Cell ◽  
Biological Effects ◽  
Protein Translation ◽  
Cancer Cell Lines ◽  
Open Reading Frames ◽  
Biologically Active ◽  
Knock Out ◽  
Reading Frames

A key question in genome research is whether biologically active proteins are restricted to the ∼20,000 canonical, well-annotated genes, or rather extend to the many non-canonical open reading frames (ORFs) predicted by genomic analyses. To address this, we experimentally interrogated 553 ORFs nominated in ribosome profiling datasets. Of these 553 ORFs, 57 (10%) induced a viability defect when the endogenous ORF was knocked out using CRISPR/Cas9 in 8 human cancer cell lines, 257 (46%) showed evidence of protein translation when ectopically expressed in HEK293T cells, and 401 (73%) induced gene expression changes measured by transcriptional profiling following ectopic expression across 4 cell types. CRISPR tiling and start codon mutagenesis indicated that the biological effects of these non-canonical ORFs required their translation as opposed to RNA-mediated effects. We selected one of these ORFs, G029442--renamed GREP1 (Glycine-Rich Extracellular Protein-1)--for further characterization. We found that GREP1 encodes a secreted protein highly expressed in breast cancer, and its knock-out in 263 cancer cell lines showed preferential essentiality in breast cancer derived lines. Analysis of the secretome of GREP1-expressing cells showed increased abundance of the oncogenic cytokine GDF15, and GDF15 supplementation mitigated the growth inhibitory effect of GREP1 knock-out. Taken together, these experiments suggest that the non-canonical ORFeome is surprisingly rich in biologically active proteins and potential cancer therapeutic targets deserving of further study.

scholarly journals The CAR mRNA-Interaction Surface is a Zipper Extension of the Ribosome A Site

2022 ◽  
Author(s):  
Carol Dalgarno ◽  
Kristen Scopino ◽  
Mitsu Raval ◽  
Clara Nachmanoff ◽  
Eric Sakkas ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Clustering Analysis ◽  
Translational Regulation ◽  
Nucleotide Substitution ◽  
Nucleotide Position ◽  
Sequence Specificity ◽  
Dynamics Simulations ◽  
A Site ◽  
Interaction Surface

The ribosome CAR interaction surface behaves like an extension of the decoding center A site and has H-bond interactions with the +1 codon that is next in line to enter the A site. Through molecular dynamics simulations, we investigated the codon sequence specificity of this CAR-mRNA interaction and discovered a strong preference for GCN codons, suggesting that there may be a sequence-dependent layer of translational regulation dependent on the CAR interaction surface. Dissection of the CAR-mRNA interaction through nucleotide substitution experiments showed that the first nucleotide of the +1 codon dominates over the second nucleotide position, consistent with an energetically favorable zipper-like activity that emanates from the A site through the CAR-mRNA interface. The +1 codon/CAR interaction is also affected by the identity of nucleotide 3 of +1 GCN codons which influences the stacking of G and C. Clustering analysis suggests that the A site decoding center adopts different neighborhood substates that depend on the identity of the +1 codon.

Hierarchy of π-Stacking Determines the Conformational Preference of Bis-Squaraines

2020 ◽  
Author(s):  
Abhishek Singh ◽  
Reman K. Singh ◽  
G Naresh Patwari
Keyword(s):  
Hydrogen Bonding ◽  
Rational Design ◽  
Biological Molecules ◽  
Conformational Space ◽  
X Ray Crystallography ◽  
Simple Strategy ◽  
Induced Folding ◽  
Π Stacking ◽  
Varying Length ◽  
Dynamics Simulations

The rational design of conformationally controlled foldable modules can lead to a deeper insight into the conformational space of complex biological molecules where non-covalent interactions such as hydrogen bonding and π-stacking are known to play a pivotal role. Squaramides are known to have excellent hydrogen bonding capabilities and hence, are ideal molecules for designing foldable modules that can mimic the secondary structures of bio-molecules. The π-stacking induced folding of bis-squaraines tethered using aliphatic primary and secondary-diamine linkers of varying length is explored with a simple strategy of invoking small perturbations involving the length linkers and degree of substitution. Solution phase NMR investigations in combination with molecular dynamics simulations suggest that bis-squaraines predominantly exist as extended conformations. Structures elucidated by X-ray crystallography confirmed a variety of folded and extended secondary conformations including hairpin turns and 𝛽-sheets which are determined by the hierarchy of π-stacking relative to N–H···O hydrogen bonds.

Hierarchy of π-Stacking Determines the Conformational Preference of Bis-Squaraines

2020 ◽  
Author(s):  
Abhishek Singh ◽  
Reman K. Singh ◽  
G Naresh Patwari
Keyword(s):  
Hydrogen Bonding ◽  
Rational Design ◽  
Biological Molecules ◽  
Conformational Space ◽  
X Ray Crystallography ◽  
Simple Strategy ◽  
Induced Folding ◽  
Π Stacking ◽  
Varying Length ◽  
Dynamics Simulations

The rational design of conformationally controlled foldable modules can lead to a deeper insight into the conformational space of complex biological molecules where non-covalent interactions such as hydrogen bonding and π-stacking are known to play a pivotal role. Squaramides are known to have excellent hydrogen bonding capabilities and hence, are ideal molecules for designing foldable modules that can mimic the secondary structures of bio-molecules. The π-stacking induced folding of bis-squaraines tethered using aliphatic primary and secondary-diamine linkers of varying length is explored with a simple strategy of invoking small perturbations involving the length linkers and degree of substitution. Solution phase NMR investigations in combination with molecular dynamics simulations suggest that bis-squaraines predominantly exist as extended conformations. Structures elucidated by X-ray crystallography confirmed a variety of folded and extended secondary conformations including hairpin turns and 𝛽-sheets which are determined by the hierarchy of π-stacking relative to N–H···O hydrogen bonds.

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