Abstract
The CIRCE element is known to be the target for the HrcA repressor and involved in the temperature-dependent gene regulation for groESL operon and/or dnaK operon in a large variety of microorganisms. We have already reported that the transcription of the groESL1 operon and the groEL2 gene in Synechocystis sp. strain PCC 6803 is derepressed by the hrcA disruption under normal conditions. However, the level of these groE mRNAs in the hrcA mutant increased further upon heat shock or irradiation, suggesting that the transcription is regulated by a mechanism other than the CIRCE/HrcA system. We found that the groE induction in the mutant is enhanced by light and this light acceleration is inhibited by DCMU. A well conserved sequence was found upstream of the groESL1 promoter. In order to identify a novel cis-element, upstream regions were fused to a reporter gene and the groE promoter analysis is in progress.
