[1] pfl RNAs are consistently present in genomic locations that likely correspond to the 5' untranslated regions (5' UTRs) of protein-coding genes.

This overlap suggests that the alternate secondary structures of pfl RNA and the transcription terminator stem-loops compete with each other, and this is a common mechanism for cis gene control in bacteria.

pfl RNAs are common among species of orders Actinomycetales and Clostridiales, the classes Alphaproteobacteria and Betaproteobacteria and the genus Deinococcus.

Experimental evidence already supported the hypothesis that pfl RNAs function as cis regulatory elements,[2] before the ligand was confirmed to be ZTP, as well as ZMP (also called AICAR), in 2015.

Another gene commonly associated with pfl RNAs is purH, which catalyzes the formylation of the intermediate AICAR in de novo synthesis of purines.