ArcZ's modes of action. ArcZ can activate the translation of mRNA (green panel). (A) ArcZ interacts with the 5′-UTR region of the rpoS mRNA and releases its ribosome-binding site (RBS), which is initially involved in a hairpin structure, allowing for the translation of rpoS. (B) Additionally, during the transcription of rpoS, ArcZ prevents the Rho termination factor from binding to the mRNA, thus blocking premature termination. ArcZ can also repress the translation of mRNA (red panel), such as with mutS or flhDC. (C) ArcZ can repress translation by binding to the RBS of the mRNA, preventing access of the ribosome. Additionally, it can bind upstream of the RBS, such as with pecT or flhD, forming a secondary structure that is incompatible with translation. (D) ArcZ can also bind to the coding region of the mRNA or sRNA, making it more susceptible to RNase such as with tpx and cyaR. Figure was created with BioRender.com.
