Temperature and Growth Phase Regulate the Transcription of the O-Antigen Gene Cluster of Yersinia enterocolitica O:3

Temperature seems to regulate both O-antigen gene cluster operons of Y. enterocolitica O:3 mainly during the stationary phase of growth. In exponential phase bacteria both operons are actively transcribed independent of temperature since temperature shift during exponential phase did not have signifigant effect on the luciferase activity. Dilution of stationary phase bacteria grown at RT decreases the light production very rapidly and dramatically. Our results suggest that in stationary phase Y. enterocolitica O:3 bacteria the O-antigen expression is controlled by a regulatory circuit which may include an activator at RT and/or a represser at 37°C. Further work is needed to elucidate regulatory mechanisms.