The Human Copper-Zinc Superoxide Dismutase Gene (SOD1) Proximal Promoter Is Regulated by Sp1, Egr-1, and WT1 via Non-canonical Binding Sites

Abstract

Human copper-zinc superoxide dismutase (Cu,Zn-SOD) participates in the control of reactive oxygen intermediate intracellular concentration. In this study, we show that phorbol 12-myristate 13-acetate (PMA) increases Cu,Zn-SOD mRNA expression within 30 min. The sequence between nucleotides −71 and −29 is essential for both basal and PMA-induced gene expression. This region includes an Sp1-binding site that is also recognized by a possible Sp1-like protein and by Egr-1 in a PMA-inducible manner. Egr-1 and two splicing variants of the Egr-related protein WT1 were able to transactivate the SOD1 promoter in co-transfection experiments. Sp1 and the possible Sp1-like proteins bind to two overlapping, but distinct sequences. However, Egr-1 and Sp1 seem to interact with two sites that are either identical or very close to each other. None of these sites fit the consensus sequences previously reported for these proteins. Analysis of various mutants of theSOD1 proximal promoter revealed that the region that binds Sp1 and Egr-1 is required for both basal and Egr-1-driven expression. Interplay between different members of the Sp1 family, Egr-1, and different splicing variants of WT1 in the SOD1 proximal promoter may provide clues about the physiological function of Cu,Zn-SOD. Human copper-zinc superoxide dismutase (Cu,Zn-SOD) participates in the control of reactive oxygen intermediate intracellular concentration. In this study, we show that phorbol 12-myristate 13-acetate (PMA) increases Cu,Zn-SOD mRNA expression within 30 min. The sequence between nucleotides −71 and −29 is essential for both basal and PMA-induced gene expression. This region includes an Sp1-binding site that is also recognized by a possible Sp1-like protein and by Egr-1 in a PMA-inducible manner. Egr-1 and two splicing variants of the Egr-related protein WT1 were able to transactivate the SOD1 promoter in co-transfection experiments. Sp1 and the possible Sp1-like proteins bind to two overlapping, but distinct sequences. However, Egr-1 and Sp1 seem to interact with two sites that are either identical or very close to each other. None of these sites fit the consensus sequences previously reported for these proteins. Analysis of various mutants of theSOD1 proximal promoter revealed that the region that binds Sp1 and Egr-1 is required for both basal and Egr-1-driven expression. Interplay between different members of the Sp1 family, Egr-1, and different splicing variants of WT1 in the SOD1 proximal promoter may provide clues about the physiological function of Cu,Zn-SOD. superoxide dismutases Zn-SOD, copper-zinc superoxide dismutase phorbol 12-myristate 13-acetate electrophoretic mobility shift assay. Superoxide dismutases (SODs)1 are found in all aerobic organisms and are thought to participate in the detoxification of reactive oxygen intermediates by catalyzing superoxide anion (O·̄2) dismutation, yielding hydrogen peroxide (H2O2) and molecular oxygen (O2) (1Fridovich I. Annu. Rev. Biochem. 1995; 64: 97-112Crossref PubMed Scopus (2691) Google Scholar). Three distinct SODs have been described in mammalian cells: a mitochondrial manganese-associated SOD, whose function is likely to detoxify superoxide anion generated by partial O2 reduction during oxidative phosphorylation; an extracellular SOD, which is found in extracellular fluids and bound to the extracellular matrix; and a cytosolic Cu,Zn-SOD, whose endogenous role remains poorly understood (2Fridovich I. J. Biol. Chem. 1997; 272: 18515-18517Abstract Full Text Full Text PDF PubMed Scopus (1046) Google Scholar, 3Przedborski S. Schon E.A. Nat. Genet. 1998; 18: 99-100Crossref PubMed Scopus (9) Google Scholar). The fundamental importance of SOD activity is illustrated in various organisms by the phenotype of mutants that do not express a form of SOD. In bacteria and yeast, SOD deficiency leads to severe growth deficits under aerobic conditions (4Carlioz A. Touati D. EMBO J. 1986; 5: 623-630Crossref PubMed Scopus (609) Google Scholar, 5Bilinski T. Krawiec Z. Liczmanski A. Litwinska J. Biochem. Biophys. Res. Commun. 1985; 130: 533-539Crossref PubMed Scopus (132) Google Scholar). The life span ofDrosophila that lack SOD is shortened. Conversely,Drosophila that overexpress SOD and catalase can live up to 150% longer (6Phillips J.P. Campbell S.D. Michaud D. Charbonneau M. Hilliker A.J. Proc. Natl. Acad. Sci. U. S. A. 1989; 86: 2761-2765Crossref PubMed Scopus (303) Google Scholar, 7Orr W.C. Sohal R.S. Science. 1994; 263: 1128-1130Crossref PubMed Scopus (1255) Google Scholar). Manganese-associated SOD-deficient mice die shortly after birth (8Li Y. Huang T.T. Carlson E.J. Melov S. Ursell P.C. Olson J.L. Noble L.J. Yoshimura M.P. Berger C. Chan P.H. Nat. Genet. 1995; 11: 376-381Crossref PubMed Scopus (1437) Google Scholar, 9Lebovitz R.M. Zhang H. Vogel H. Cartwright Jr., J. Dionne L. Lu N. Huang S. Matzuk M.M. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 9782-9787Crossref PubMed Scopus (824) Google Scholar). Human Cu,Zn-SOD is encoded by a gene (SOD1) located in the 21q22 region (10Tan Y.H. Tischfield J. Ruddle F.H. J. Exp. Med. 1973; 137: 317-330Crossref PubMed Scopus (214) Google Scholar). This region is involved in the most common genetic disease, known as trisomy 21 or Down's syndrome. However, although a 1.5-fold increase inSOD1 gene expression may be associated with the disease, several Down's syndrome patients carrying a partial trisomy 21 have a normal Cu,Zn-SOD activity (11De La Torre L.T. Casado A. Lopez-Fernandez E. Carrascosa D. Ramirez V. Saez J. Experientia (Basel). 1996; 52: 871-873Crossref PubMed Scopus (65) Google Scholar). It has been reported that some cases of familial amyotrophic lateral sclerosis, a serious neurodegenerative disease, are associated with dominant mutations in the SOD1gene (12Rosen D.R. Siddique T. Patterson D. Figlewicz D.A. Sapp P. Hentati A. Donaldson D. Goto J. O'Regan J.P. Deng H.X. Nature. 1993; 362: 59-62Crossref PubMed Scopus (5443) Google Scholar, 13Deng H.X. Hentati A. Tainer J.A. Iqbal Z. Cayabyab A. Hung W.Y. Getzoff E.D. Hu P. Herzfeldt B. Roos R.P. Science. 1993; 261: 1047-1051Crossref PubMed Scopus (1336) Google Scholar). However, a gain of function is likely to cause familial amyotrophic lateral sclerosis, rather than a defect of Cu,Zn-SOD activity (14Yim M.B. Kang J.H. Yim H.S. Kwak H.S. Chock P.B. Stadtman E.R. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 5709-5714Crossref PubMed Scopus (428) Google Scholar). Accordingly, in mice, Cu,Zn-SOD homozygous null mutants are viable and do not exhibit the neuropathological symptoms characteristic of familial amyotrophic lateral sclerosis patients. However, these Cu,Zn-SOD−/− mice exhibit an enhanced neuronal cell death following axotomy or ischemia, suggesting a requirement for Cu,Zn-SOD under stress (15Reaume A.G. Elliott J.L. Hoffman E.K. Kowall N.W. Ferrante R.J. Siwek D.F. Wilcox H.M. Flood D.G. Beal M.F. Brown R.H.J. Scott R.W. Snider W.D. Nat. Genet. 1996; 13: 43-47Crossref PubMed Scopus (1035) Google Scholar, 16Kondo T. Reaume A.G. Huang T.T. Carlson E. Murakami K. Chen S.F. Hoffman E.K. Scott R.W. Epstein C.J. Chan P.H. J. Neurosci. 1997; 17: 4180-4189Crossref PubMed Google Scholar).Although Cu,Zn-SOD activity has been found modified in some specific situations including hematopoietic cell differentiation, aging, and some tumor cells (17Auwerx J.H. Chait A. Wolfbauer G. Deeb S.S. Blood. 1989; 74: 1807-1810Crossref PubMed Google Scholar, 18Allen R.G. Keogh B.P. Gerhard G.S. Pignolo R. Horton J. Cristofalo V.J. J. Cell. Physiol. 1995; 165: 576-587Crossref PubMed Scopus (30) Google Scholar, 19Van Driel B.E. Lyon H. Hoogenraad D.C. Anten S. Hansen U. Van N.C. Free Radical Biol. Med. 1997; 23: 435-444Crossref PubMed Scopus (61) Google Scholar), the SOD1 gene is often considered as a “housekeeping gene,” and its activity is often used as an internal control when variations of manganese-associated SOD activity are measured. We report here the analysis of the proximal region of theSOD1 gene promoter. Phorbol 12-myristate 13-acetate (PMA) was used as a model agonist to identify trans- and cis-acting factors for SOD1 gene expression. We found that SOD1 gene expression is rapidly enhanced following PMA treatment. A region between nucleotides −71 and −29 was essential for both basal and PMA-induced expression. This region could be further refined to a single Sp1/Egr-1/WT1-binding site located between nucleotides −59 and −48. These findings suggest that competition between Sp1, Egr-1, and variants of WT1 (and perhaps other Sp1- or Egr-related proteins) for the same binding site may play a role in the regulation of SOD1 gene expression in response to a variety of biological signals.DISCUSSIONWe report the analysis of the human Cu,Zn-SOD gene proximal promoter. Deletion analysis of the SOD1 gene promoter suggests the existence of several regulatory sequences spread along the 5′-flanking region of the SOD1 gene. Indeed, previous reports had allowed identification of several cis-acting sequences. Two AP-2 sites located between positions −134 and −127 and positions −118 and are involved in the promoter response Y.H. H.M. J. Biol. Chem. 1996; Full Text Full Text PDF PubMed Scopus Google Scholar). Sp1 site to and a protein site to have also been described G. H.M. G. 1996; PubMed Scopus Google Scholar). although several regulatory sequences are within of the SOD1 promoter region located between nucleotides −71 and is to provide both basal and PMA-induced promoter this we a site located between nucleotides −59 and that is able to bind Sp1 and Egr-1 following PMA treatment. This sequence can also by two splicing variants of the tumor protein the site to described by G. H.M. G. 1996; PubMed Scopus Google the site to described in this study, suggesting the existence of a between different factors for the regulation of the SOD1 of the site with consensus or sites revealed that this site not fit consensus sequences described T. E. I. H. E.A. Res. 1998; PubMed Scopus Google Scholar). In in most other sequences recognized by both Sp1 and Egr-1, the binding sites of the two proteins but are not identical C. A. G. E. D. Rev. 1996; PubMed Google Scholar). In study, Sp1 and Egr-1 sites seem to be identical or do not seem to by than two nucleotides we could not a that binding of of the two This binding sequence the of a binding site involved in regulation by members of the sequence is recognized by a possible Sp1-like the Sp1-like site the Sp1 consensus but not seem to be involved in SOD1 regulation in cells a this site not to of lack of phenotype in SOD1 null mice (15Reaume A.G. Elliott J.L. Hoffman E.K. Kowall N.W. Ferrante R.J. Siwek D.F. Wilcox H.M. Flood D.G. Beal M.F. Brown R.H.J. Scott R.W. Snider W.D. Nat. Genet. 1996; 13: 43-47Crossref PubMed Scopus (1035) Google that Cu,Zn-SOD is not for normal and but rather is involved in the response to Indeed, the phenotype described for these mice is a partial defect in following Egr-1 has been described as a in response to stress in cells V. A.J. T. Science. 1996; PubMed Scopus Google Scholar). Egr-1 regulation of the SOD1gene a between this and Cu,Zn-SOD in response to stress in Accordingly, a report has described an of Cu,Zn-SOD activity in human cells in response to stress N. S. T. R.M. D.G. Res. 1996; PubMed Scopus Google Scholar). This increase in activity in by of the SOD1 gene and was not in was not that this increase was by Egr-1, we that Egr-1 regulation of the of Cu,Zn-SOD, in an function of the tumor protein WT1 in SOD1gene regulation remains A between WT1 and has been described in several WT1 and its to in response to various S. C. P. G. D.A. 1995; PubMed Scopus Google Scholar). of endogenous WT1 by in cell T. 1996; Google Scholar). the other a role for WT1 has been of WT1 in an cell C. S. P. C. A.J. D.A. EMBO J. 1995; PubMed Scopus Google Scholar), and cell death was in and cells D.A. C. S. Med. 1996; PubMed Scopus Google Scholar), and cells A. N. A.J. A.G. Res. 1997; Google Scholar), and the cell Y. T. H. K. T. 1997; PubMed Scopus Google following WT1 In most the of WT1 to be by the splicing that the D.A. C. S. Med. 1996; PubMed Scopus Google Scholar, A. N. A.J. A.G. Res. 1997; Google Scholar). In WT1 has been described as able to of the gene. reactive oxygen intermediates are not likely to be involved in all and cells a reactive oxygen when of growth This is by of Cu,Zn-SOD L.J. 1995; Full Text PDF PubMed Scopus Google Scholar). these suggest a function for the WT1 of SOD1 regulation in the of in neuronal Superoxide dismutases (SODs)1 are found in all aerobic organisms and are thought to participate in the detoxification of reactive oxygen intermediates by catalyzing superoxide anion (O·̄2) dismutation, yielding hydrogen peroxide (H2O2) and molecular oxygen (O2) (1Fridovich I. Annu. Rev. Biochem. 1995; 64: 97-112Crossref PubMed Scopus (2691) Google Scholar). Three distinct SODs have been described in mammalian cells: a mitochondrial manganese-associated SOD, whose function is likely to detoxify superoxide anion generated by partial O2 reduction during oxidative phosphorylation; an extracellular SOD, which is found in extracellular fluids and bound to the extracellular matrix; and a cytosolic Cu,Zn-SOD, whose endogenous role remains poorly understood (2Fridovich I. J. Biol. Chem. 1997; 272: 18515-18517Abstract Full Text Full Text PDF PubMed Scopus (1046) Google Scholar, 3Przedborski S. Schon E.A. Nat. Genet. 1998; 18: 99-100Crossref PubMed Scopus (9) Google Scholar). The fundamental importance of SOD activity is illustrated in various organisms by the phenotype of mutants that do not express a form of SOD. In bacteria and yeast, SOD deficiency leads to severe growth deficits under aerobic conditions (4Carlioz A. Touati D. EMBO J. 1986; 5: 623-630Crossref PubMed Scopus (609) Google Scholar, 5Bilinski T. Krawiec Z. Liczmanski A. Litwinska J. Biochem. Biophys. Res. Commun. 1985; 130: 533-539Crossref PubMed Scopus (132) Google Scholar). The life span ofDrosophila that lack SOD is shortened. Conversely,Drosophila that overexpress SOD and catalase can live up to 150% longer (6Phillips J.P. Campbell S.D. Michaud D. Charbonneau M. Hilliker A.J. Proc. Natl. Acad. Sci. U. S. A. 1989; 86: 2761-2765Crossref PubMed Scopus (303) Google Scholar, 7Orr W.C. Sohal R.S. Science. 1994; 263: 1128-1130Crossref PubMed Scopus (1255) Google Scholar). Manganese-associated SOD-deficient mice die shortly after birth (8Li Y. Huang T.T. Carlson E.J. Melov S. Ursell P.C. Olson J.L. Noble L.J. Yoshimura M.P. Berger C. Chan P.H. Nat. Genet. 1995; 11: 376-381Crossref PubMed Scopus (1437) Google Scholar, 9Lebovitz R.M. Zhang H. Vogel H. Cartwright Jr., J. Dionne L. Lu N. Huang S. Matzuk M.M. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 9782-9787Crossref PubMed Scopus (824) Google Scholar). Human Cu,Zn-SOD is encoded by a gene (SOD1) located in the 21q22 region (10Tan Y.H. Tischfield J. Ruddle F.H. J. Exp. Med. 1973; 137: 317-330Crossref PubMed Scopus (214) Google Scholar). This region is involved in the most common genetic disease, known as trisomy 21 or Down's syndrome. However, although a 1.5-fold increase inSOD1 gene expression may be associated with the disease, several Down's syndrome patients carrying a partial trisomy 21 have a normal Cu,Zn-SOD activity (11De La Torre L.T. Casado A. Lopez-Fernandez E. Carrascosa D. Ramirez V. Saez J. Experientia (Basel). 1996; 52: 871-873Crossref PubMed Scopus (65) Google Scholar). It has been reported that some cases of familial amyotrophic lateral sclerosis, a serious neurodegenerative disease, are associated with dominant mutations in the SOD1gene (12Rosen D.R. Siddique T. Patterson D. Figlewicz D.A. Sapp P. Hentati A. Donaldson D. Goto J. O'Regan J.P. Deng H.X. Nature. 1993; 362: 59-62Crossref PubMed Scopus (5443) Google Scholar, 13Deng H.X. Hentati A. Tainer J.A. Iqbal Z. Cayabyab A. Hung W.Y. Getzoff E.D. Hu P. Herzfeldt B. Roos R.P. Science. 1993; 261: 1047-1051Crossref PubMed Scopus (1336) Google Scholar). However, a gain of function is likely to cause familial amyotrophic lateral sclerosis, rather than a defect of Cu,Zn-SOD activity (14Yim M.B. Kang J.H. Yim H.S. Kwak H.S. Chock P.B. Stadtman E.R. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 5709-5714Crossref PubMed Scopus (428) Google Scholar). Accordingly, in mice, Cu,Zn-SOD homozygous null mutants are viable and do not exhibit the neuropathological symptoms characteristic of familial amyotrophic lateral sclerosis patients. However, these Cu,Zn-SOD−/− mice exhibit an enhanced neuronal cell death following axotomy or ischemia, suggesting a requirement for Cu,Zn-SOD under stress (15Reaume A.G. Elliott J.L. Hoffman E.K. Kowall N.W. Ferrante R.J. Siwek D.F. Wilcox H.M. Flood D.G. Beal M.F. Brown R.H.J. Scott R.W. Snider W.D. Nat. Genet. 1996; 13: 43-47Crossref PubMed Scopus (1035) Google Scholar, 16Kondo T. Reaume A.G. Huang T.T. Carlson E. Murakami K. Chen S.F. Hoffman E.K. Scott R.W. Epstein C.J. Chan P.H. J. Neurosci. 1997; 17: 4180-4189Crossref PubMed Google Scholar). Cu,Zn-SOD activity has been found modified in some specific situations including hematopoietic cell differentiation, aging, and some tumor cells (17Auwerx J.H. Chait A. Wolfbauer G. Deeb S.S. Blood. 1989; 74: 1807-1810Crossref PubMed Google Scholar, 18Allen R.G. Keogh B.P. Gerhard G.S. Pignolo R. Horton J. Cristofalo V.J. J. Cell. Physiol. 1995; 165: 576-587Crossref PubMed Scopus (30) Google Scholar, 19Van Driel B.E. Lyon H. Hoogenraad D.C. Anten S. Hansen U. Van N.C. Free Radical Biol. Med. 1997; 23: 435-444Crossref PubMed Scopus (61) Google Scholar), the SOD1 gene is often considered as a “housekeeping gene,” and its activity is often used as an internal control when variations of manganese-associated SOD activity are measured. We report here the analysis of the proximal region of theSOD1 gene promoter. Phorbol 12-myristate 13-acetate (PMA) was used as a model agonist to identify trans- and cis-acting factors for SOD1 gene expression. We found that SOD1 gene expression is rapidly enhanced following PMA treatment. A region between nucleotides −71 and −29 was essential for both basal and PMA-induced expression. This region could be further refined to a single Sp1/Egr-1/WT1-binding site located between nucleotides −59 and −48. These findings suggest that competition between Sp1, Egr-1, and variants of WT1 (and perhaps other Sp1- or Egr-related proteins) for the same binding site may play a role in the regulation of SOD1 gene expression in response to a variety of biological report the analysis of the human Cu,Zn-SOD gene proximal promoter. Deletion analysis of the SOD1 gene promoter suggests the existence of several regulatory sequences spread along the 5′-flanking region of the SOD1 gene. Indeed, previous reports had allowed identification of several cis-acting sequences. Two AP-2 sites located between positions −134 and −127 and positions −118 and are involved in the promoter response Y.H. H.M. J. Biol. Chem. 1996; Full Text Full Text PDF PubMed Scopus Google Scholar). Sp1 site to and a protein site to have also been described G. H.M. G. 1996; PubMed Scopus Google Scholar). although several regulatory sequences are within of the SOD1 promoter region located between nucleotides −71 and is to provide both basal and PMA-induced promoter this we a site located between nucleotides −59 and that is able to bind Sp1 and Egr-1 following PMA treatment. This sequence can also by two splicing variants of the tumor protein the site to described by G. H.M. G. 1996; PubMed Scopus Google the site to described in this study, suggesting the existence of a between different factors for the regulation of the SOD1 of the site with consensus or sites revealed that this site not fit consensus sequences described T. E. I. H. E.A. Res. 1998; PubMed Scopus Google Scholar). In in most other sequences recognized by both Sp1 and Egr-1, the binding sites of the two proteins but are not identical C. A. G. E. D. Rev. 1996; PubMed Google Scholar). In study, Sp1 and Egr-1 sites seem to be identical or do not seem to by than two nucleotides we could not a that binding of of the two This binding sequence the of a binding site involved in regulation by members of the sequence is recognized by a possible Sp1-like the Sp1-like site the Sp1 consensus but not seem to be involved in SOD1 regulation in cells a this site not to of lack of phenotype in SOD1 null mice (15Reaume A.G. Elliott J.L. Hoffman E.K. Kowall N.W. Ferrante R.J. Siwek D.F. Wilcox H.M. Flood D.G. Beal M.F. Brown R.H.J. Scott R.W. Snider W.D. Nat. Genet. 1996; 13: 43-47Crossref PubMed Scopus (1035) Google that Cu,Zn-SOD is not for normal and but rather is involved in the response to Indeed, the phenotype described for these mice is a partial defect in following Egr-1 has been described as a in response to stress in cells V. A.J. T. Science. 1996; PubMed Scopus Google Scholar). Egr-1 regulation of the SOD1gene a between this and Cu,Zn-SOD in response to stress in Accordingly, a report has described an of Cu,Zn-SOD activity in human cells in response to stress N. S. T. R.M. D.G. Res. 1996; PubMed Scopus Google Scholar). This increase in activity in by of the SOD1 gene and was not in was not that this increase was by Egr-1, we that Egr-1 regulation of the of Cu,Zn-SOD, in an function of the tumor protein WT1 in SOD1gene regulation remains A between WT1 and has been described in several WT1 and its to in response to various S. C. P. G. D.A. 1995; PubMed Scopus Google Scholar). of endogenous WT1 by in cell T. 1996; Google Scholar). the other a role for WT1 has been of WT1 in an cell C. S. P. C. A.J. D.A. EMBO J. 1995; PubMed Scopus Google Scholar), and cell death was in and cells D.A. C. S. Med. 1996; PubMed Scopus Google Scholar), and cells A. N. A.J. A.G. Res. 1997; Google Scholar), and the cell Y. T. H. K. T. 1997; PubMed Scopus Google following WT1 In most the of WT1 to be by the splicing that the D.A. C. S. Med. 1996; PubMed Scopus Google Scholar, A. N. A.J. A.G. Res. 1997; Google Scholar). In WT1 has been described as able to of the gene. reactive oxygen intermediates are not likely to be involved in all and cells a reactive oxygen when of growth This is by of Cu,Zn-SOD L.J. 1995; Full Text PDF PubMed Scopus Google Scholar). these suggest a function for the WT1 of SOD1 regulation in the of in neuronal We report the analysis of the human Cu,Zn-SOD gene proximal promoter. Deletion analysis of the SOD1 gene promoter suggests the existence of several regulatory sequences spread along the 5′-flanking region of the SOD1 gene. Indeed, previous reports had allowed identification of several cis-acting sequences. Two AP-2 sites located between positions −134 and −127 and positions −118 and are involved in the promoter response Y.H. H.M. J. Biol. Chem. 1996; Full Text Full Text PDF PubMed Scopus Google Scholar). Sp1 site to and a protein site to have also been described G. H.M. G. 1996; PubMed Scopus Google Scholar). although several regulatory sequences are within of the SOD1 promoter region located between nucleotides −71 and is to provide both basal and PMA-induced promoter this we a site located between nucleotides −59 and that is able to bind Sp1 and Egr-1 following PMA treatment. This sequence can also by two splicing variants of the tumor protein the site to described by G. H.M. G. 1996; PubMed Scopus Google the site to described in this study, suggesting the existence of a between different factors for the regulation of the SOD1 gene. of the site with consensus or sites revealed that this site not fit consensus sequences described T. E. I. H. E.A. Res. 1998; PubMed Scopus Google Scholar). In in most other sequences recognized by both Sp1 and Egr-1, the binding sites of the two proteins but are not identical C. A. G. E. D. Rev. 1996; PubMed Google Scholar). In study, Sp1 and Egr-1 sites seem to be identical or do not seem to by than two nucleotides we could not a that binding of of the two This binding sequence the of a binding site involved in regulation by members of the sequence is recognized by a possible Sp1-like the Sp1-like site the Sp1 consensus but not seem to be involved in SOD1 regulation in cells a this site not to of The lack of phenotype in SOD1 null mice (15Reaume A.G. Elliott J.L. Hoffman E.K. Kowall N.W. Ferrante R.J. Siwek D.F. Wilcox H.M. Flood D.G. Beal M.F. Brown R.H.J. Scott R.W. Snider W.D. Nat. Genet. 1996; 13: 43-47Crossref PubMed Scopus (1035) Google that Cu,Zn-SOD is not for normal and but rather is involved in the response to Indeed, the phenotype described for these mice is a partial defect in following Egr-1 has been described as a in response to stress in cells V. A.J. T. Science. 1996; PubMed Scopus Google Scholar). Egr-1 regulation of the SOD1gene a between this and Cu,Zn-SOD in response to stress in Accordingly, a report has described an of Cu,Zn-SOD activity in human cells in response to stress N. S. T. R.M. D.G. Res. 1996; PubMed Scopus Google Scholar). This increase in activity in by of the SOD1 gene and was not in was not that this increase was by Egr-1, we that Egr-1 regulation of the of Cu,Zn-SOD, in an The function of the tumor protein WT1 in SOD1gene regulation remains A between WT1 and has been described in several WT1 and its to in response to various S. C. P. G. D.A. 1995; PubMed Scopus Google Scholar). of endogenous WT1 by in cell T. 1996; Google Scholar). the other a role for WT1 has been of WT1 in an cell C. S. P. C. A.J. D.A. EMBO J. 1995; PubMed Scopus Google Scholar), and cell death was in and cells D.A. C. S. Med. 1996; PubMed Scopus Google Scholar), and cells A. N. A.J. A.G. Res. 1997; Google Scholar), and the cell Y. T. H. K. T. 1997; PubMed Scopus Google following WT1 In most the of WT1 to be by the splicing that the D.A. C. S. Med. 1996; PubMed Scopus Google Scholar, A. N. A.J. A.G. Res. 1997; Google Scholar). In WT1 has been described as able to of the gene. reactive oxygen intermediates are not likely to be involved in all and cells a reactive oxygen when of growth This is by of Cu,Zn-SOD L.J. 1995; Full Text PDF PubMed Scopus Google Scholar). these suggest a function for the WT1 of SOD1 regulation in the of in neuronal We P. for the of the Egr-1 expression and for the of WT1 expression We are to V. and A. for and to A. D. and M. for and of the