The rpsL -leader. Representative structures are shown for reference species, each corresponding to the consensus terminal structure of elements found in closely related species. Boxes indicate terminator T-stretches. Black arrows indicate putative anti-terminator structures. (a) Elements found upstream of the rpsL gene in Listeria, Xanthomonas, Pseudomonas and Rickettsia genera. (b) rpsL-leader found upstream of the gene fusA in streptococci.