Increased synthesis of signaling molecules coincides with reversible inhibition of nucleolytic activity during postirradiation recovery of Deinococcus radiodurans.

Deinococcus radiodurans tolerates extensive DNA damage and exhibits differential expression of various genes associated with the growth of the organism and DNA repair. In cells treated with gamma radiation, the levels of cyclic AMP (cAMP) and ATP increased rapidly by differentially regulating adenylyl cyclase (AC) and 2'3' cAMP phosphodiesterase. The levels of cAMP, ATP, AC and protein kinases were high when phosphodiesterase activity was low. These cells exhibited in vivo inhibition of nucleolytic function by reversible protein phosphorylation and contained the comparatively higher levels of total phosphoproteins. We suggest that Deinococcus, a prokaryote, uses DNA damage-induced signaling mechanism as evidenced by gamma radiation-induced synthesis of secondary messengers and signaling enzymes.