scholarly journals Evolutionary Dynamics of Abundant Stop Codon Readthrough

2016 ◽  
Vol 33 (12) ◽  
pp. 3108-3132 ◽  
Author(s):  
Irwin Jungreis ◽  
Clara S. Chan ◽  
Robert M. Waterhouse ◽  
Gabriel Fields ◽  
Michael F. Lin ◽  
...  
2016 ◽  
Author(s):  
Irwin Jungreis ◽  
Clara S Chan ◽  
Robert M Waterhouse ◽  
Gabriel Fields ◽  
Michael F Lin ◽  
...  

AbstractTranslational stop codon readthrough was virtually unknown in eukaryotic genomes until recent developments in comparative genomics and new experimental techniques revealed evidence of readthrough in hundreds of fly genes and several human, worm, and yeast genes. Here, we use the genomes of 21 species ofAnophelesmosquitoes and improved comparative techniques to identify evolutionary signatures of conserved, functional readthrough of 353 stop codons in the malaria vector,Anopheles gambiae, and 51 additionalDrosophila melanogasterstop codons, with several cases of double and triple readthrough including readthrough of two adjacent stop codons, supporting our earlier prediction of abundant readthrough in pancrustacea genomes. Comparisons betweenAnophelesandDrosophilaallow us to transcend the static picture provided by single-clade analysis to explore the evolutionary dynamics of abundant readthrough. We find that most differences between the readthrough repertoires of the two species are due to readthrough gain or loss in existing genes, rather than to birth of new genes or to gene death; that RNA structures are sometimes gained or lost while readthrough persists; and that readthrough is more likely to be lost at TAA and TAG stop codons. We also determine which characteristic properties of readthrough predate readthrough and which are clade-specific. We estimate that there are more than 600 functional readthrough stop codons inA. gambiaeand 900 inD. melanogaster. We find evidence that readthrough is used to regulate peroxisomal targeting in two genes. Finally, we use the sequenced centipede genome to refine the phylogenetic extent of abundant readthrough.


2012 ◽  
Vol 287 (21) ◽  
pp. 17765-17776 ◽  
Author(s):  
Yoshihide Yamaguchi ◽  
Akiko Hayashi ◽  
Celia W. Campagnoni ◽  
Akio Kimura ◽  
Takashi Inuzuka ◽  
...  

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1230
Author(s):  
Sawsan Napthine ◽  
Chris H. Hill ◽  
Holly C. M. Nugent ◽  
Ian Brierley

The product of the interferon-stimulated gene C19orf66, Shiftless (SHFL), restricts human immunodeficiency virus replication through downregulation of the efficiency of the viral gag/pol frameshifting signal. In this study, we demonstrate that bacterially expressed, purified SHFL can decrease the efficiency of programmed ribosomal frameshifting in vitro at a variety of sites, including the RNA pseudoknot-dependent signals of the coronaviruses IBV, SARS-CoV and SARS-CoV-2, and the protein-dependent stimulators of the cardioviruses EMCV and TMEV. SHFL also reduced the efficiency of stop-codon readthrough at the murine leukemia virus gag/pol signal. Using size-exclusion chromatography, we confirm the binding of the purified protein to mammalian ribosomes in vitro. Finally, through electrophoretic mobility shift assays and mutational analysis, we show that expressed SHFL has strong RNA binding activity that is necessary for full activity in the inhibition of frameshifting, but shows no clear specificity for stimulatory RNA structures.


Open Biology ◽  
2016 ◽  
Vol 6 (11) ◽  
pp. 160246 ◽  
Author(s):  
Julia Hofhuis ◽  
Fabian Schueren ◽  
Christopher Nötzel ◽  
Thomas Lingner ◽  
Jutta Gärtner ◽  
...  

Translational readthrough gives rise to C-terminally extended proteins, thereby providing the cell with new protein isoforms. These may have different properties from the parental proteins if the extensions contain functional domains. While for most genes amino acid incorporation at the stop codon is far lower than 0.1%, about 4% of malate dehydrogenase (MDH1) is physiologically extended by translational readthrough and the actual ratio of MDH1x (e x tended protein) to ‘normal' MDH1 is dependent on the cell type. In human cells, arginine and tryptophan are co-encoded by the MDH1x UGA stop codon. Readthrough is controlled by the 7-nucleotide high-readthrough stop codon context without contribution of the subsequent 50 nucleotides encoding the extension. All vertebrate MDH1x is directed to peroxisomes via a hidden peroxisomal targeting signal (PTS) in the readthrough extension, which is more highly conserved than the extension of lactate dehydrogenase B. The hidden PTS of non-mammalian MDH1x evolved to be more efficient than the PTS of mammalian MDH1x. These results provide insight into the genetic and functional co-evolution of these dually localized dehydrogenases.


2019 ◽  
Vol 47 (21) ◽  
pp. 11326-11343 ◽  
Author(s):  
Kristýna Poncová ◽  
Susan Wagner ◽  
Myrte Esmeralda Jansen ◽  
Petra Beznosková ◽  
Stanislava Gunišová ◽  
...  

Abstract Ribosome was long considered as a critical yet passive player in protein synthesis. Only recently the role of its basic components, ribosomal RNAs and proteins, in translational control has begun to emerge. Here we examined function of the small ribosomal protein uS3/Rps3, earlier shown to interact with eukaryotic translation initiation factor eIF3, in termination. We identified two residues in consecutive helices occurring in the mRNA entry pore, whose mutations to the opposite charge either reduced (K108E) or increased (R116D) stop codon readthrough. Whereas the latter increased overall levels of eIF3-containing terminating ribosomes in heavy polysomes in vivo indicating slower termination rates, the former specifically reduced eIF3 amounts in termination complexes. Combining these two mutations with the readthrough-reducing mutations at the extreme C-terminus of the a/Tif32 subunit of eIF3 either suppressed (R116D) or exacerbated (K108E) the readthrough phenotypes, and partially corrected or exacerbated the defects in the composition of termination complexes. In addition, we found that K108 affects efficiency of termination in the termination context-specific manner by promoting incorporation of readthrough-inducing tRNAs. Together with the multiple binding sites that we identified between these two proteins, we suggest that Rps3 and eIF3 closely co-operate to control translation termination and stop codon readthrough.


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