rsmZ

RsmZ is a small regulatory RNA (sRNA) found in several Gram-negative bacteria, most notably in Pseudomonas species. It belongs to the RsmY/RsmZ family of non-coding RNAs and functions as a post-transcriptional regulator by binding RNA-binding proteins of the CsrA/RsmA family. By sequestering RsmA, RsmZ reduces the ability of RsmA to repress target mRNAs, thereby promoting translation of downstream genes.

RsmZ expression is controlled by the GacS/GacA two-component system. In response to environmental cues, GacA activates transcription of rsmZ (and related sRNAs such as rsmY), which titrate RsmA away from target messages.

The RsmZ molecule typically contains multiple stem-loop structures and conserved GGA sequence motifs that contribute to RsmA binding. The resulting derepression affects a broad regulon, including genes involved in exopolysaccharide production, biofilm formation, motility, and virulence traits. The balance between RsmA activity and RsmZ/other sRNAs determines phenotypic outcomes such as planktonic growth versus biofilm lifestyle.

RsmZ functions in a regulatory network with other sRNAs and factors, and its activity can influence pathogenic traits in Pseudomonas aeruginosa and related bacteria. It is often studied alongside RsmY and other Rsm sRNAs to understand post-transcriptional control of virulence and metabolism.

See also RsmY, RsmX, GacS/GacA, CsrA/RsmA.