Four histidine kinases are main sensors of hydrogen peroxide-stress signals in Synechocystis

Abstract

Oxidative stress is one of the major environmental factors for all living organisms. DNA microarray analysis revealed that incubation of cyanobacterial cells of Synechocystis sp. PCC 6803 with 0.25 mM H₂O₂ dramatically changed the pattern of genome-wide expression of genes. It induced the expression of 225 genes and repressed the expression of 320 genes. Screening of the mutant libraries of histidine kinases (Hik) by means of the H₂O₂-inducible expression of genes revealed that four histidine kinases, Hik33, Hik34, Hik2, Hik41 and a transcription factor PerR are involved in the perception of H₂O₂ signals and in the regulation of the H₂O₂-inducible expression, with induction factors higher than four, of 25, 1, 6, 2 and 6 genes, respectively. Further analysis will be discussed.