The Downstream-peptide motif refers to a conserved RNA structure identified by bioinformatics in the cyanobacterial genera Synechococcus and Prochlorococcus and one phage that infects such bacteria.

[1] It was hypothesized that Downstream-peptide RNAs correspond to riboswitches, based on multiple lines of evidence.

[1] First, glnA RNAs are often located in the presumed 5′ untranslated regions of multiple classes of genes involved in nitrogen metabolism.

Finally, the observation of regulation of a downstream ORF by nitrogen availability also suggests a cis-regulatory role of the element.

This hypothesis is supported by the finding that expression of the DUF4278-containing glutamine synthetase inhibitory factor IF17 encoding gene gifB was shown to be regulated by the structurally related glnA RNA motif.