CIRCADIAN CLOCK MUTANTS OF CYANOBACTERIA

A diverse set of circadian clock mutants was isolated in a cyanobacter ial strain that carries a bacterial luciferase reporter gene attached to a clock-controlled promoter. Among 150,000 clones of chemically mut agenized bioluminescent cells, 12 mutants were isolated that exhibit a broad spectrum of periods (between 16 and 60 hours), and 5 mutants we re found that show a variety of unusual patterns, including arrhythmia . These mutations appear to be clock-specific. Moreover, it was demons trated that in this cyanobacterium it is possible to clone mutant gene s by complementation, which provides a means to genetically dissect th e circadian mechanism.