In molecular biology, 5' ureB sRNA is a
small RNA. It is located at the
5' end of the ureB
gene in the
urease gene cluster and is antisense to ureB. Its expression is regulated by the arsS/arsR
two-component regulatory system, arsS downregulates 5' ureB sRNA expression under acidic conditions leading to an increase in ureB expression. 5' ureB sRNA suppresses
transcription of ureA and ureB by
base-pairing with ureAB
mRNA resulting in premature termination of the transcript to the 5' of ureB.[1][2]