Role of nitric oxide in regulating the expression of histone mRNA

Nitric oxide (NO) transmits the intercellular and intracellular signals to suppress cell growth, DNA replication, and the expression of genes essential for cell proliferation. The NO effect on the expression of the histone H2B gene was studied in mouse and human cells. Cell incubation in the presence of chemical donors of NO quickly decreased the H2B mRNA content. Luciferase activity assays showed that NO inhibited the expression of the reporter gene controlled by the H2B histone gene promoter. A decrease in H2B mRNA in the cell corresponded to the NO-dependent decrease in reporter gene expression. Thus, NO negatively regulated transcription of the histone H2B gene by suppressing its promoter. Inhibition of histone mRNA expression was assumed to play an important role in the cytostatic effect of NO.