Abstract
Among the 3 dnaK genes of cyanobacteria Synachococcus sp. PCC7942, only dnaK2 exhibits heat shock response, as well as induction upon exporsure to high light and salt stress.
In this work, we are analyzing the possible involvement of DnaK2 on psbAII transcriptional regulation, based on the interaction observed between DnaK2 and RNase E using yeast two-hybrid analysis. In Microcystis, RNase E is thought to be involved in stabilizing the psbAII mRNA through targeting the AU-box of the untranslated resion(UTR). Our experiment revealed that the stability of the S. 7942 psbAII mRNA is linked to AU-box, based on our analysis using UTR-lacZ fusion. Additionally, over-expression of DnaK2 resulted in stable psbAII mRNA under growth light condition. We postulate that psbAII is stabilized due to the inability of the DnaK2-bound RNase E to associate with the AU-box.
