CrcZ is a

small RNA Small RNA (sRNA) are polymeric RNA molecules that are less than 200 nucleotides in length, and are usually non-coding RNA, non-coding. RNA silencing is often a function of these molecules, with the most common and well-studied example being RNA int ...

found in

Pseudomonas ''Pseudomonas'' is a genus of Gram-negative bacteria belonging to the family Pseudomonadaceae in the class Gammaproteobacteria. The 348 members of the genus demonstrate a great deal of metabolic diversity and consequently are able to colonize a ...

bacteria, which acts as a global regulator of carbon catabolite repression. In P. aeruginosa, CrcZ is responsible for sequestering the protein Crc. Crc is an RNA-binding global regulator, which acts by inhibiting the translation of the transcriptional regulator AlkS.

Function

In P. aeruginosa, CrcZ is a 407-nt long RNA which contains 5 CA-rich motifs. CrcZ expression is regulated by the two-component system CbrA/CbrB, in response to the availability of different carbon sources. As the Crc protein inhibits translation of transcriptional regulators by binding to and occluding the translational initiation site, sequestration of Crc by CrcZ binding means that Crc is unable to inhibit translation and transcriptional regulators, such as AlkS, are freely translated. Expression of CrcZ is dependent on the carbon sources available to the bacteria; in the presence of preferred carbon sources (such as succinate), CrcZ expression is low, and catabolite repression is high. In the presence of poor sources of carbon, such as mannitol, CrcZ expression is high, allowing the inhibition of Crc and a subsequent decrease in catabolite repression occurs.

Function

References

Further reading