Ribosomal protein S1 plays a critical role in horizontal gene transfer by mediating the expression of foreign mRNAs

The emergence of multi-antibiotic resistant bacteria is one of the largest threats to global heath. This rise is due to the genomic plasticity of bacteria, allowing rapid acquisition of antibiotic resistance through the uptake of foreign DNA (i.e. horizontal gene transfer, HGT). This genomic plasticity is not limited to DNA from bacteria, highly divergent (trans-kingdom) mRNA have been reported to drive translation in E. coli. Trans-kingdom activity has been attributed to mRNA tertiary structure suggesting the bacterial translation machinery bottle-necks HGT, restricting the expression of foreign DNA. However, here we show that tertiary structure is not responsible for ribosome recruitment and that the translation efficiency is dependent on ribosomal protein S1 and an A-rich Shine-Dalgarno-like element. The S1-facilitated ability of ribosomes to identify and exploit A-rich sequences in foreign RNA highlights the important role that S1 plays in horizontal gene transfer, the robustness of canonical prokaryotic translation, and bacterial evolution.