Identification of Circadian Clock Genes Affecting Synechoccocus elongatus PCC 7942

The cyanobacterium, Synechococcus elongatus PCC 7942, are the only known prokaryote that possesses a circadian clock. Because of its genetic simplicity, S. elongatus is an excellent model to study components of the clock. The focus of this research is to screen for mutants in genes that modify the clock. An insertion library has been constructed through transposon mutagenesis and was screened for circadian mutants using a bioluminescent assay.  Using this data, we chose a set of 95 mutant genes that were arrhythmic, period or phase mutants, relative to wild type. We performed additional bioluminescent assays on a turn table with a CCD camera in order to confirm these circadian phenotypes.  We found four genes, trpA, gyrA, ftsZ and a gene encoding for an aluminum resistance protein that displayed an altered period and phase.  Currently, we are performing bioinformatic analyses in an attempt to understand their respective functions with respect to the circadian clock. Through this research, we are discovering other genes that affect the clock, which will lead to a better understanding of the circadian clock in cyanobacteria.