scholarly journals Translational coupling by modulation of feedback repression in the IF3 operon of Escherichia coli

1997 ◽  
Vol 94 (17) ◽  
pp. 9208-9213 ◽  
Author(s):  
C. Chiaruttini ◽  
M. Milet ◽  
M. Springer
Keyword(s):  
Escherichia Coli ◽  
Translational Coupling

scholarly journals Regulation of Escherichia coli secA by Cellular Protein Secretion Proficiency Requires an Intact Gene X Signal Sequence and an Active Translocon

1998 ◽  
Vol 180 (19) ◽  
pp. 5240-5242 ◽  
Author(s):  
Donald Oliver ◽  
Jessica Norman ◽  
Shameema Sarker
Keyword(s):  
Escherichia Coli ◽  
Protein Secretion ◽  
Signal Sequence ◽  
Cellular Protein ◽  
X Protein ◽  
Translational Coupling ◽  
Intact Gene

ABSTRACT secA is translationally regulated by the protein secretion proficiency state of the Escherichia coli cell. This regulation was explored by making signal sequence mutations in the gene upstream of secA, gene X, which promotessecA translational coupling. Gene X signal sequence mutants were constitutive for secA expression, whileprlA alleles partially restored secAregulation. These results show that interaction of the pre-gene X protein with the translocon is required for proper secAregulation. Furthermore, gene X signal sequence mutations disruptedsecA regulation only in the cis configuration. We propose that nascent pre-gene X protein interacts with the translocon during its secretion to constitute the secretion sensor.

scholarly journals Ribosome recycling is not critical for translational coupling in Escherichia coli

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Kazuki Saito ◽  
Rachel Green ◽  
Allen R Buskirk
Keyword(s):  
Escherichia Coli ◽  
Coupling Efficiency ◽  
Ribosome Profiling ◽  
Ribosome Recycling Factor ◽  
Translational Coupling ◽  
E Coli ◽  
Major Mechanism ◽  
Ribosome Density ◽  
Reporter Assays ◽  
Complete Translation

We used ribosome profiling to characterize the biological role of ribosome recycling factor (RRF) in Escherichia coli. As expected, RRF depletion leads to enrichment of post-termination 70S complexes in 3′-UTRs. We also observe that elongating ribosomes are unable to complete translation because they are blocked by non-recycled ribosomes at stop codons. Previous studies have suggested a role for recycling in translational coupling within operons; if a ribosome remains bound to an mRNA after termination, it may re-initiate downstream. We found, however, that RRF depletion did not significantly affect coupling efficiency in reporter assays or in ribosome density genome-wide. These findings argue that re-initiation is not a major mechanism of translational coupling in E. coli. Finally, RRF depletion has dramatic effects on the activity of ribosome rescue factors tmRNA and ArfA. Our results provide a global view of the effects of the loss of ribosome recycling on protein synthesis in E. coli.

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