TY - JOUR
T1 - An intronic NF-κB element is essential for induction of the human manganese superoxide dismutase gene by tumor necrosis factor-α and interleukin-1β
AU - Xu, Yong
AU - Kiningham, Kelley K.
AU - Devalaraja, Madhav N.
AU - Yeh, Che Chung
AU - Majima, Hideyuki
AU - Kasarskis, Edward J.
AU - St. Clair, Daret K.
PY - 1999/9
Y1 - 1999/9
N2 - Tumor necrosis factor-α (TNF) and interleukin-1β (IL-1) are cytokines that induce expression of various genes through activation of the redox- sensitive transcription factor nuclear factor-κB (NF-κB). We have previously cloned the entire human MnSOD (SOD2) gene and found several NF- κB-binding sites in the 5' and 3' flanking and intronic regions. To test whether these putative NF-κB-binding sites are able to respond to TNF and IL-1. We performed induction analysis using various deletion constructs ligated to a luciferase reporter gene. We found that the 5' and 3' flanking regions containing several NF-κB-binding sites do not mediate MnSOD induction by TNF or IL-1. When a 342-bp intron 2 fragment containing NF-κB, C/EBP, and NF-1 binding sites was linked to the basal promoter of the SOD2 gene, transcriptional activities were significantly increased in response to TNF and IL-1 in an orientation- and position-independent manner. To accurately identify the element that is most critical for the enhancer activity, deletions and specific mutations of each individual site were studied. The results indicated that the NF-κB binding site is essential but not sufficient for TNF- or IL-1-mediated induction. Furthermore, NF-κB elements in the 5' and 3' flanking regions could be made to function in TNF or IL-1 induction when they were transposed to the intronic fragment. Taken together, these results suggest that an NF-κB element and its location in the SOD2 gene is critical for TNF/IL-1-mediated induction. However, a complex interaction between NF-κB and other transcription elements is needed for a high-level induction.
AB - Tumor necrosis factor-α (TNF) and interleukin-1β (IL-1) are cytokines that induce expression of various genes through activation of the redox- sensitive transcription factor nuclear factor-κB (NF-κB). We have previously cloned the entire human MnSOD (SOD2) gene and found several NF- κB-binding sites in the 5' and 3' flanking and intronic regions. To test whether these putative NF-κB-binding sites are able to respond to TNF and IL-1. We performed induction analysis using various deletion constructs ligated to a luciferase reporter gene. We found that the 5' and 3' flanking regions containing several NF-κB-binding sites do not mediate MnSOD induction by TNF or IL-1. When a 342-bp intron 2 fragment containing NF-κB, C/EBP, and NF-1 binding sites was linked to the basal promoter of the SOD2 gene, transcriptional activities were significantly increased in response to TNF and IL-1 in an orientation- and position-independent manner. To accurately identify the element that is most critical for the enhancer activity, deletions and specific mutations of each individual site were studied. The results indicated that the NF-κB binding site is essential but not sufficient for TNF- or IL-1-mediated induction. Furthermore, NF-κB elements in the 5' and 3' flanking regions could be made to function in TNF or IL-1 induction when they were transposed to the intronic fragment. Taken together, these results suggest that an NF-κB element and its location in the SOD2 gene is critical for TNF/IL-1-mediated induction. However, a complex interaction between NF-κB and other transcription elements is needed for a high-level induction.
UR - http://www.scopus.com/inward/record.url?scp=0032588841&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032588841&partnerID=8YFLogxK
U2 - 10.1089/104454999314999
DO - 10.1089/104454999314999
M3 - Article
C2 - 10492402
AN - SCOPUS:0032588841
SN - 1044-5498
VL - 18
SP - 709
EP - 722
JO - DNA and Cell Biology
JF - DNA and Cell Biology
IS - 9
ER -