Spl and C/EBP-related factor regulate the transcription of human Cu/Zn SOD gene

• Published in: Gene 1996, Vol.178 (1), p.177-185
• Main Authors: Seo, Seong Jin, Kim, Hong Tae, Cho, Ginam, Rho, Hyune Mo, Jung, Guhung
• Format: Article
• Language: English
• Subjects: Cotransfection; DNase I footprinting assay; EMSA; Induction; NF-IL6; Oxidative stress; Positive regulatory element; Transcription factors
• ISSN: 0378-1119; 1879-0038
• DOI: 10.1016/0378-1119(96)00383-6

The Cu/Zn superoxide dismutase (SOD1) is one of the' key enzymes that protect cells against oxidative stress. It catalyzes the dismutation of superoxide radicals (O 2 −) to oxygen and hydrogen peroxide. To study the transcriptional regulation of the human Cu/Zn SOD gene, we began by analyzing the 1.5-kb upstream region of the gene (see Kim et al., 1994). The element from nucleotides (nt) -116 to -45 increased the transcriptional activity of Cu/Zn SOD. Analyses by DNase I footprinting and electrophoretic mobility shift assay (EMSA) showed that Sp1 binds to the region from nt -104 to -89 and C/EBP-related factors to the region from nt -64 to -55. Studies using two mutant versions of this promoter, in which the Spl and C/EBP-related factor binding sites were deleted, respectively, revealed that Spl and C/EBP-related factors activate the transcription of SOD1 gene. An Spl expression plasmid, pPacSpl, stimulated the SOD1-linked CAT expression. Cotransfection of the element from nt -116 to -45 with the C/EBPα expression vector, pMSV-C/EBP, increased the transcriptional activity of the Cu/Zn SOD in HepG2 cells, but barely in HeLa cells. Because Spl is a ubiquitously expressed transcriptional factor, the binding of Spl to the proximal upstream region of the Cu/Zn SOD might explain the expression of Cu/Zn SOD in a wide variety of cells.