PrfA thermoregulator UTR

The PrfA thermoregulator UTR is an RNA element found in the 5' UTR of the prfA gene. In Listeria monocytogenes, virulence genes are maximally expressed at 37 degrees Celsius, almost silent at 30 degrees Celsius and controlled by PrfA, a transcriptional activator whose expression is thermoregulated. It has been shown that the untranslated mRNA (UTR) preceding prfA, forms a secondary structure, which masks the ribosome binding region. The secondary structure of this motif forms a hairpin. The Shine-Dalgarno sequence (SD) is partly masked by the most conserved stem-loop of the secondary structure. It is thought that at 37 degrees Celsius the SD sequence is unmasked.