It should be noted that stalling on intact mRNAs can also occur for instance due to rare codon stretches, translational misreading, problematic polypeptide stretches or weak termination codons ( Hayes and Sauer, 2003 Sunohara et al., 2004 Li et al., 2006, 2007 Singh et al., 2008 Garza-Sánchez et al., 2009 Zaher and Green, 2009, 2010, 2011 Giudice and Gillet, 2013 Petropoulos et al., 2014 Sharma et al., 2014 Samatova et al., 2020). Such impediments lead to the formation of so-called no-go complexes, in which the ribosome cannot proceed further on the mRNA ( Figure 1A). Environmental and cellular agents can cause impediments due to chemical mRNA damage for example by alkylation or oxidation ( Wurtmann and Wolin, 2009 Simms and Zaher, 2016 Yan and Zaher, 2019 Thomas et al., 2020). When ribosomes encounter impediments during translation, they can stall on the mRNA instead of continuing protein synthesis. The importance of rescue pathways for bacterial survival suggests they may represent novel targets for the development of new antimicrobial agents against multi-drug resistant pathogenic bacteria. Finally, we discuss the recent findings of ribosome-associated quality control in particular bacterial lineages mediated by RqcH and RqcP. This review highlights the recent developments in our mechanistic understanding of bacterial ribosomal rescue systems, including drop-off, trans-translation mediated by transfer-messenger RNA and small protein B, ribosome rescue by the alternative rescue factors ArfA and ArfB, as well as Bacillus ribosome rescue factor A, an additional rescue system found in some Gram-positive bacteria, such as Bacillus subtilis. In addition, some of these pathways target the damaged mRNA and the incomplete nascent polypeptide chain for degradation.
#Jc sauer model 1913 free#
Bacteria have evolved a diverse array of rescue pathways to remove the stalled ribosomes from the aberrant mRNA and return them to the free pool of actively translating ribosomes. Ribosomes that become stalled on truncated or damaged mRNAs during protein synthesis must be rescued for the cell to survive.
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