The unicellular cyanobacteriumSynechococcus elongatusPCC 7942 is the model organism for studying prokaryotic circadian rhythms. AlthoughS. elongatusdoes not display an easily measurable overt circadian behavior, its gene expression is under circadian control; hence, a “behavior” is created by linking a cyanobacterial promoter to either the bacterialluxABor fireflylucluciferase genes to create reporter fusions whose activity can be easily monitored by bioluminescence. Numerous vectors have been created in our lab for introducing luciferase reporter genes into theS. elongatuschromosome. A choice of methods and equipment to detect light production from the luciferase fusions provides a means for high-throughput, automated mutant screens as well as testing rhythms from two promoter fusions within the same cell culture.
