HUMAN INDUCIBLE NITRIC-OXIDE SYNTHASE GENE IS TRANSCRIPTIONALLY REGULATED BY NUCLEAR FACTOR-KAPPA-B DEPENDENT MECHANISM

We previously showed a sequence of the 5'-flanking region of the human inducible nitric oxide synthase (hiNOS) gene that included putative c is-acting elements. A reporter plasmid containing the 5'-flanking regi on of the hiNOS gene upstream from its reporter gene was constructed, and then transiently or stably transfected into human cells known to e xpress the hiNOS gene following cytokine stimulation. The transfected cells showed the inducibility of the reporter activity following inter leukin-1 beta stimulation. Reporter inducibility disappeared in cells transfected with a plasmid mutated in the putative nuclear factor (NF) -kappa B binding region. In addition, the induction was inhibited by a treatment of anti-oxidant, pyrrolidinedithiocarbamate, known as an NF -kappa B inhibitor. Our results demonstrate that the promoter includin g NF-kappa B region is functional and that the hiNOS gene is transcrip tionally regulated via NF-kappa B activation in human cells. (C) 1996 Academic Press, Inc.