ArcZ is an Hfq binding RNA that functions as an antisense regulator of a number of protein coding genes.

This non-coding RNA was discovered in the bacteria Escherichia coli during a large scale computational screen for transcription signals and genomic features of known small RNA-encoding genes.

This precursor is unstable and is processed into an abundant fragment ~58 nucleotides which represents the 3' end of the initial transcript.

The stability and abundance of the shorter 3' transcript is confirmed in both Northern blotting and deep sequencing analysis.

[5] In plant pathogen Erwinia amylovora ArcZ was shown to positively control the type III secretion system (T3SS), amylovoran exopolysaccharide production, biofilm formation, and bacterial motility, but it negatively regulates bacterial attachment.