Figure 1: Internal ribosome entry sites trigger protein synthesis in bacteria. | Nature

Figure 1: Internal ribosome entry sites trigger protein synthesis in bacteria.

From: Signals across domains of life

Figure 1

Structures called internal ribosome entry sites (IRESs) in RNA viruses such as the dicistrovirus promote protein synthesis in eukaryotes (organisms including plants, animals and fungi). Colussi et al.2 report the surprising finding that the dicistrovirus IRES can initiate protein synthesis in the bacterium Escherichia coli (a prokaryote). a, The authors constructed a messenger RNA that incorporates the IRES and introduced this to E. coli cells, where the IRES recruits the bacterial ribosome (the protein-synthesizing apparatus) to the mRNA. b, They propose that the ribosome then repositions itself to a ribosome-binding site (RBS) and an AUG start codon (an RNA sequence that initiates translation). c, Another hypothesis is that, after recruitment of the first ribosome, a second ribosome binds to the RBS and AUG codon.

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