scholarly journals Translational buffering by ribosome stalling in upstream open reading frames

2022 ◽  
Author(s):  
Ty A Bottorff ◽  
Adam P Geballe ◽  
Arvind Rasi Subramaniam
Keyword(s):  
Protein Expression ◽  
Kinetic Modeling ◽  
Human Cells ◽  
Open Reading Frames ◽  
General Mechanism ◽  
Developmental Transitions ◽  
Alternative Models ◽  
Ribosome Stalling ◽  
Upstream Open Reading Frames ◽  
Reading Frames

Upstream open reading frames (uORFs) are present in over half of all human mRNAs. uORFs can potently regulate the translation of downstream open reading frames by several mechanisms: siphoning away scanning ribosomes, regulating re-initiation, and allowing interactions between scanning and elongating ribosomes. However, the consequences of these different mechanisms for the regulation of protein expression remain incompletely understood. Here, we performed systematic measurements on the uORF-containing 5′ UTR of the cytomegaloviral UL4 mRNA to test alternative models of uORF-mediated regulation in human cells. We find that a terminal diproline-dependent elongating ribosome stall in the UL4 uORF prevents decreases in main ORF translation when ribosome loading onto the mRNA is reduced. This uORF-mediated buffering is insensitive to the location of the ribosome stall along the uORF. Computational kinetic modeling based on our measurements suggests that scanning ribosomes dissociate rather than queue when they collide with stalled elongating ribosomes within the UL4 uORF. We identify several human uORFs that repress main ORF translation via a similar terminal diproline motif. We propose that ribosome stalls in uORFs provide a general mechanism for buffering against reductions in main ORF translation during stress and developmental transitions.

scholarly journals Genetic variants in progranulin upstream open reading frames increase downstream protein expression

2021 ◽  
Author(s):  
Alexandros Frydas ◽  
Rita Cacace ◽  
Julie van der Zee ◽  
Christine Van Broeckhoven ◽  
Eline Wauters
Keyword(s):  
Protein Expression ◽  
Genetic Variants ◽  
Open Reading Frames ◽  
Upstream Open Reading Frames ◽  
Reading Frames

scholarly journals Conserved Peptide Upstream Open Reading Frames Act Via Ribosome Stalling to Regulate Translation in Response to Environmental Signals.

2021 ◽  
Author(s):  
Barry Causier ◽  
Tayah Hopes ◽  
Mary McKay ◽  
Zachary Paling ◽  
Brendan Davies
Keyword(s):  
Growth And Development ◽  
Open Reading Frames ◽  
Peptide Sequence ◽  
Dependent Manner ◽  
Environmental Signals ◽  
Ribosome Stalling ◽  
Mrna Transcripts ◽  
Upstream Open Reading Frames ◽  
Fine Tune ◽  
Reading Frames

The regulation of protein synthesis plays a key role in growth and development in all organisms. Upstream open reading frames (uORFs) are commonly found in eukaryotic mRNA transcripts and typically inhibit translation of downstream ORFs, in part by stalling ribosomes. Conserved peptide uORFs (CPuORFs) are a rare subset of uORFs, some of which conditionally regulate translation. Here we identify three Arabidopsis CPuORFs that specifically regulate translation of any downstream ORF, in response to the agriculturally significant environmental signals, heat shock and water limitation. Mechanistically, we provide evidence that CPuORF translation causes ribosome stalling, in a peptide sequence-dependent manner, attenuating translation of downstream ORFs. We propose a model in which plant CPuORFs are not simply on/off switches for translation, but rather act conditionally, along a continuum, to fine-tune translation dynamically.

scholarly journals Plants Utilise Ancient Conserved Peptide Upstream Open Reading Frames as Environmental Sensors

2021 ◽  
Author(s):  
Barry Causier ◽  
Tayah Hopes ◽  
Mary McKay ◽  
Zachary Paling ◽  
Brendan Davies
Keyword(s):  
Protein Synthesis ◽  
Growth And Development ◽  
Open Reading Frames ◽  
Environmental Sensors ◽  
Environmental Signals ◽  
Broad Application ◽  
Ribosome Stalling ◽  
Mrna Transcripts ◽  
Upstream Open Reading Frames ◽  
Reading Frames

The regulation of protein synthesis plays an important role in growth and development in all organisms. Upstream open reading frames (uORFs) are commonly found in eukaryotic mRNA transcripts and typically attenuate the translation of associated downstream main ORFs (mORFs). Conserved peptide uORFs (CPuORFs) are a rare subset of uORFs, some of which have been shown to conditionally regulate translation by ribosome stalling. Here we identify three Arabidopsis CPuORFs of ancient origin that regulate translation of any downstream ORF, in response to agriculturally significant environmental signals: heat stress and water limitation. We provide evidence that different sequence classes of CPuORF stall ribosomes during different phases of translation and show that plant CPuORFs act as environmental sensors that can be utilised as inducible regulators of translation with broad application.

scholarly journals A First Step towards Learning which uORFs Regulate Gene Expression

2006 ◽  
Vol 3 (2) ◽  
pp. 109-122 ◽  
Author(s):  
◽  
Christopher H. Bryant ◽  
Graham J.L. Kemp ◽  
Marija Cvijovic
Keyword(s):  
Gene Expression ◽  
Inductive Logic ◽  
Preliminary Evidence ◽  
Open Reading Frames ◽  
Yeast Saccharomyces Cerevisiae ◽  
Regulate Gene Expression ◽  
Integrative System ◽  
Upstream Open Reading Frames ◽  
Reading Frames ◽  
Regulate Gene

Summary We have taken a first step towards learning which upstream Open Reading Frames (uORFs) regulate gene expression (i.e., which uORFs are functional) in the yeast Saccharomyces cerevisiae. We do this by integrating data from several resources and combining a bioinformatics tool, ORF Finder, with a machine learning technique, inductive logic programming (ILP). Here, we report the challenge of using ILP as part of this integrative system, in order to automatically generate a model that identifies functional uORFs. Our method makes searching for novel functional uORFs more efficient than random sampling. An attempt has been made to predict novel functional uORFs using our method. Some preliminary evidence that our model may be biologically meaningful is presented.

scholarly journals Translation of ABCE1 Is Tightly Regulated by Upstream Open Reading Frames in Human Colorectal Cells

Biomedicines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 911
Author(s):  
Joana Silva ◽  
Pedro Nina ◽  
Luísa Romão
Keyword(s):  
Translational Regulation ◽  
Regulatory Elements ◽  
Ribosome Profiling ◽  
Leader Sequence ◽  
Open Reading Frames ◽  
Regulatory Function ◽  
Coding Sequence ◽  
Abc Protein ◽  
Upstream Open Reading Frames ◽  
Reading Frames

ATP-binding cassette subfamily E member 1 (ABCE1) belongs to the ABC protein family of transporters; however, it does not behave as a drug transporter. Instead, ABCE1 actively participates in different stages of translation and is also associated with oncogenic functions. Ribosome profiling analysis in colorectal cancer cells has revealed a high ribosome occupancy in the human ABCE1 mRNA 5′-leader sequence, indicating the presence of translatable upstream open reading frames (uORFs). These cis-acting translational regulatory elements usually act as repressors of translation of the main coding sequence. In the present study, we dissect the regulatory function of the five AUG and five non-AUG uORFs identified in the human ABCE1 mRNA 5′-leader sequence. We show that the expression of the main coding sequence is tightly regulated by the ABCE1 AUG uORFs in colorectal cells. Our results are consistent with a model wherein uORF1 is efficiently translated, behaving as a barrier to downstream uORF translation. The few ribosomes that can bypass uORF1 (and/or uORF2) must probably initiate at the inhibitory uORF3 or uORF5 that efficiently repress translation of the main ORF. This inhibitory property is slightly overcome in conditions of endoplasmic reticulum stress. In addition, we observed that these potent translation-inhibitory AUG uORFs function equally in cancer and in non-tumorigenic colorectal cells, which is consistent with a lack of oncogenic function. In conclusion, we establish human ABCE1 as an additional example of uORF-mediated translational regulation and that this tight regulation contributes to control ABCE1 protein levels in different cell environments.

scholarly journals Disrupting upstream translation in mRNAs is associated with human disease

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
David S. M. Lee ◽  
Joseph Park ◽  
Andrew Kromer ◽  
Aris Baras ◽  
Daniel J. Rader ◽  
...  
Keyword(s):  
Protein Expression ◽  
Biological Significance ◽  
Ribosome Profiling ◽  
Open Reading Frames ◽  
Protein Coding ◽  
Stop Codons ◽  
Human Genes ◽  
Strong Negative Selection ◽  
Disease Associations ◽  
Reading Frames

AbstractRibosome-profiling has uncovered pervasive translation in non-canonical open reading frames, however the biological significance of this phenomenon remains unclear. Using genetic variation from 71,702 human genomes, we assess patterns of selection in translated upstream open reading frames (uORFs) in 5’UTRs. We show that uORF variants introducing new stop codons, or strengthening existing stop codons, are under strong negative selection comparable to protein-coding missense variants. Using these variants, we map and validate gene-disease associations in two independent biobanks containing exome sequencing from 10,900 and 32,268 individuals, respectively, and elucidate their impact on protein expression in human cells. Our results suggest translation disrupting mechanisms relating uORF variation to reduced protein expression, and demonstrate that translation at uORFs is genetically constrained in 50% of human genes.

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