Circadian orchestration of gene expression in cyanobacteria

Y. Liu, N. F. Tsinoremas, C. H. Johnson, N. V. Lebedeva, S. S. Golden, M. Ishiura, T. Kondo

Research output: Contribution to journalArticlepeer-review

302 Scopus citations


We wanted to identify genes that are controlled by the circadian clock in the prokaryotic cyanobacterium Synechococcus sp. strain PCC 7942. To use luciferase as a reporter to monitor gene expression, bacterial luciferase genes (luxAB) were inserted randomly into the Synechococcus genome by conjugation with Escherichia coli and subsequent homologous recombination. The resulting transformed clones were then screened for bioluminescence using a newly developed cooled-CCD camera system. We screened transformed Synechococcus colonies and recovered ~800 clones whose bioluminescence was bright enough to be easily monitored by the screening apparatus. Unexpectedly, the bioluminescence expression patterns of almost all of these 800 colonies clearly manifested circadian rhythmicity. These rhythms exhibited a range of waveforms and amplitudes, and they also showed a variety of phase relationships. We also found bioluminescence rhythms expressed by cyanobacterial colonies in which the luciferase gene set was coupled to the promoters of several known genes. Together, these results indicate that control of gene expression by circadian clocks may be more widespread than expected thus far. Moreover, our results show that screening organisms in which promoterless luciferase genes have been inserted randomly throughout the genome by homologous recombination provides an extremely sensitive method to explore differential gene expression.

Original languageEnglish (US)
Pages (from-to)1469-1478
Number of pages10
JournalGenes and Development
Issue number12
StatePublished - Jun 15 1995


  • Bioluminescence
  • Synechococcus
  • circadian rhythms
  • cyanobacteria
  • luciferase
  • luxAB genes

ASJC Scopus subject areas

  • Genetics
  • Developmental Biology


Dive into the research topics of 'Circadian orchestration of gene expression in cyanobacteria'. Together they form a unique fingerprint.

Cite this