Nrf1 and Nrf2 Play Distinct Roles in Activation of Antioxidant Response Element-dependent Genes

Abstract

Nrf1 is a member of the vertebrate Cap'n'Collar (CNC) transcription factor family that commonly contains a unique basic-leucine zipper domain. Among CNC family members, Nrf2 is known to regulate a battery of antioxidant and xenobiotic-metabolizing enzyme genes through the antioxidant response element (ARE). Although Nrf1 has also been shown to bind the ARE, it is unclear whether it plays a distinct role from Nrf2 in regulating genes with this element. To address this issue in vivo, we generated mice bearing a hepatocyte-specific disruption of the Nrf1 gene. AlthoughNrf2 knock-out mice did not exhibit liver damage when they were maintained in an unstressed condition, hepatocyte-specific deletion of Nrf1 caused liver damage resembling the human disease non-alcoholic steatohepatitis. Gene expression analysis revealed that the disruption of Nrf1 causes stress that activates a number of ARE-driven genes in an Nrf2-dependent manner, indicating that Nrf2 cannot compensate completely for loss of Nrf1 function in the liver. In contrast, expression of metallothionein-1 and -2 (MT1 and MT2) genes, each of which harbors at least one ARE in its regulatory region, was decreased in the Nrf1-null mutant mice. Whereas Nrf1 and Nrf2 bound the MT1 ARE with comparable affinity, Nrf1 preferentially activated the reporter gene expression through the MT1 ARE. This study has, thus, identified the first ARE-dependent gene that relies exclusively on Nrf1, suggesting that it plays a distinct functional role in regulating ARE-driven genes. Nrf1 is a member of the vertebrate Cap'n'Collar (CNC) transcription factor family that commonly contains a unique basic-leucine zipper domain. Among CNC family members, Nrf2 is known to regulate a battery of antioxidant and xenobiotic-metabolizing enzyme genes through the antioxidant response element (ARE). Although Nrf1 has also been shown to bind the ARE, it is unclear whether it plays a distinct role from Nrf2 in regulating genes with this element. To address this issue in vivo, we generated mice bearing a hepatocyte-specific disruption of the Nrf1 gene. AlthoughNrf2 knock-out mice did not exhibit liver damage when they were maintained in an unstressed condition, hepatocyte-specific deletion of Nrf1 caused liver damage resembling the human disease non-alcoholic steatohepatitis. Gene expression analysis revealed that the disruption of Nrf1 causes stress that activates a number of ARE-driven genes in an Nrf2-dependent manner, indicating that Nrf2 cannot compensate completely for loss of Nrf1 function in the liver. In contrast, expression of metallothionein-1 and -2 (MT1 and MT2) genes, each of which harbors at least one ARE in its regulatory region, was decreased in the Nrf1-null mutant mice. Whereas Nrf1 and Nrf2 bound the MT1 ARE with comparable affinity, Nrf1 preferentially activated the reporter gene expression through the MT1 ARE. This study has, thus, identified the first ARE-dependent gene that relies exclusively on Nrf1, suggesting that it plays a distinct functional role in regulating ARE-driven genes. One of the unique features of transcription factors is that they can be categorized into structurally related groups (or families) based on their DNA binding motifs. It appears that in addition to their common basic functions each member within a specific transcription factor family is likely to have acquired novel properties during its molecular evolution. Consequently, it is probable that a family of transcription factors collectively possesses abilities that enable individual members to fine-tune the expression of target genes during disparate biological processes through a common cis-acting element. The Cap'n'Collar (CNC) 3The abbreviations used are: CNC, Cap'n'Collar; NASH, non-alcoholic steatohepatitis; ARE, antioxidant response element; ER, endoplasmic reticulum; MT, metallothionein; RT, reverse transcription; NQO1, NAD(P)H dehydrogenase quinone 1; GCLC, glutamate-cysteine ligase catalytic subunit; HO-1, heme oxygenase-1; GSTP1, glutathione S-transferase π1. 3The abbreviations used are: CNC, Cap'n'Collar; NASH, non-alcoholic steatohepatitis; ARE, antioxidant response element; ER, endoplasmic reticulum; MT, metallothionein; RT, reverse transcription; NQO1, NAD(P)H dehydrogenase quinone 1; GCLC, glutamate-cysteine ligase catalytic subunit; HO-1, heme oxygenase-1; GSTP1, glutathione S-transferase π1. family of transcription factors has been well described. It comprises four closely related factors, Nrf1, Nrf2, Nrf3, and p45 NF-E2 (1Motohashi H. O'Connor T. Katsuoka F. Engel J.D. Yamamoto M. Gene (Amst.). 2002; 294: 1-12Crossref PubMed Scopus (377) Google Scholar, 2Blank V. J. Mol. Biol. 2008; 376: 913-925Crossref PubMed Scopus (114) Google Scholar). These CNC members contain a CNC domain juxtaposed with a conserved basic region-leucine zipper (bZip) domain. The CNC domain is represented in an evolutionally distant homologue, SKN1 in the nematode Caenorhabditis elegans (3An J.H. Blackwell T.K. Genes Dev. 2003; 17: 1882-1893Crossref PubMed Scopus (497) Google Scholar). Although SKN1 binds to DNA as a monomer, all vertebrate CNC members each heterodimerize with one of three small Maf proteins, and the resulting heterodimers bind to the Maf recognition element (TGCTGA(G/C)TCAGCA) or related sequences. Because the vertebrate CNC members cannot bind to Maf recognition element sequences as monomers, small Maf proteins are indispensable partners of CNC bZip transcription factors (1Motohashi H. O'Connor T. Katsuoka F. Engel J.D. Yamamoto M. Gene (Amst.). 2002; 294: 1-12Crossref PubMed Scopus (377) Google Scholar, 2Blank V. J. Mol. Biol. 2008; 376: 913-925Crossref PubMed Scopus (114) Google Scholar). The Maf recognition element-related sequence that is referred to as an antioxidant or electrophile response element (ARE/EpRE; hereafter designated ARE for simplicity) has been identified in the transcriptional regulatory regions of antioxidant and xenobiotic-metabolizing enzyme genes (1Motohashi H. O'Connor T. Katsuoka F. Engel J.D. Yamamoto M. Gene (Amst.). 2002; 294: 1-12Crossref PubMed Scopus (377) Google Scholar, 2Blank V. J. Mol. Biol. 2008; 376: 913-925Crossref PubMed Scopus (114) Google Scholar) and is thought to account for the coordinated up-regulation of these genes during oxidative stress. The ARE has been shown to recruit Nrf2 and small Maf proteins (1Motohashi H. O'Connor T. Katsuoka F. Engel J.D. Yamamoto M. Gene (Amst.). 2002; 294: 1-12Crossref PubMed Scopus (377) Google Scholar, 2Blank V. J. Mol. Biol. 2008; 376: 913-925Crossref PubMed Scopus (114) Google Scholar). In Nrf2-null mutant mice the up-regulation of many antioxidant and detoxification enzyme genes has been found to be severely impaired (4Itoh K. Chiba T. Takahashi S. Ishii T. Igarashi K. Katoh Y. Oyake T. Hayashi N. Satoh K. Hatayama I. Yamamoto M. Nabeshima Y. Biochem. Biophys. Res. Commun. 1997; 236: 313-322Crossref PubMed Scopus (3088) Google Scholar). Nrf1 has also been shown to contribute to the regulation of ARE-dependent genes (5Chen L. Kwong M. Lu R. Ginzinger D. Lee C. Leung L. Chan J.Y. Mol. Cell. Biol. 2003; 23: 4673-4686Crossref PubMed Scopus (108) Google Scholar, 6Kwong M. Kan Y.W. Chan J.Y. J. Biol. Chem. 1999; 274: 37491-37498Abstract Full Text Full Text PDF PubMed Scopus (148) Google Scholar). Unlike Nrf2-null mice, Nrf1-null mice die by embryonic day 13.5 (E13.5) due to anemia (7Chan J.Y. Kwong M. Lu R. Chang J. Wang B. Yen T.S.B. Kan Y.W. EMBO J. 1998; 17: 1779-1787Crossref PubMed Scopus (214) Google Scholar). Furthermore, Nrf1:Nrf2 compound mutant mice die by E11.5, suggesting that Nrf2 can compensate, albeit partially, for the absence of Nrf1 in embryonic mice (8Leung L. Kwong M. Hou S. Lee C. Chan J.Y. J. Biol. Chem. 2003; 278: 48021-48029Abstract Full Text Full Text PDF PubMed Scopus (235) Google Scholar). Based on the observation that an evolutionally distant CNC homolog SKN1 also contributes to the induction of antioxidant genes (9Inoue H. Hisamoto N. An J.H. Oliveira R.P. Nishida E. Blackwell T.K. Matsumoto K. Genes Dev. 2005; 19: 2278-2283Crossref PubMed Scopus (282) Google Scholar), it can be hypothesized that the regulation of antioxidant genes is one of the original functions descended from a common ancestral CNC protein. It is clear that Nrf1 and Nrf2 have acquired specific functions during their molecular evolution. It has been reported that hepatocyte-specific conditional targeting of the Nrf1 gene (Nrf1 cKO) causes a liver pathology resembling human non-alcoholic steatohepatitis (NASH) (10Xu Z. Chen L. Leung L. Yen T.S.B. Lee C. Chan J.Y. Proc. Natl. Acad. Sci. U. S. A. 2005; 102: 4120-4125Crossref PubMed Scopus (225) Google Scholar); this previous study also reported that the expression of several ARE-dependent genes was decreased in the livers of Nrf1 cKO mice, suggesting that Nrf1 has an overlapping function with Nrf2 in the regulation of antioxidant and detoxifying genes. In stark contrast, however, Nrf2-null mutant mice do not show any liver damage when housed in an unstressed environment (11Chanas S.A. Jiang Q. McMahon M. McWalter G.K. McLellan L.I. Elcombe C.R. Henderson C.J. Wolf C.R. Moffat G.J. Itoh K. Yamamoto M. Hayes J.D. Biochem. J. 2002; 365: 405-416Crossref PubMed Scopus (360) Google Scholar). Thus, perturbations in the expression of antioxidant genes in Nrf1 cKO mice appear unlikely to account for the NASH-like disorder. Collectively, these observations suggest that Nrf1 possesses unique functions that are not exhibited by Nrf2. To execute its unique activity, Nrf1 protein possesses several distinct domains that are conserved among cross-species Nrf1 homologues (12Zhang Y. Crouch D.H. Yamamoto M. Hayes J.D. Biochem. J. 2006; 399: 373-385Crossref PubMed Scopus (96) Google Scholar). For instance, Nrf1 has an endoplasmic reticulum (ER) targeting sequence in its N-terminal domain that is responsible for it being anchored to the ER membrane and an Asn/Ser/Thr-rich (NST) domain through which it is glycosylated within the ER (13Zhang Y. Lucocq J.M. Yamamoto M. Hayes J.D. Biochem. J. 2007; 408: 161-172Crossref PubMed Scopus (30) Google Scholar). It has also been reported that Nrf1 is cleaved and translocated from the ER to the nucleus in response to ER stress (14Wang W. Chan J.Y. J. Biol. Chem. 2006; 281: 19676-19687Abstract Full Text Full Text PDF PubMed Scopus (131) Google Scholar), although the functional contribution of Nrf1 to the ER stress response has not been well described. Because the distinct phenotypes of Nrf1 and Nrf2 knock-out mice are highly likely to be caused by differences in the expression of their relevant target genes, it is necessary to examine gene expression profiles in mutant mice to understand the molecular basis for the severe consequences disruption of In this study we generated hepatocyte-specific Nrf1 cKO mice and gene expression To expression of Nrf2 target genes in the liver was by the loss of Nrf1 in Nrf2-dependent manner, indicating that of Nrf1 target genes causes an of the response also found that several ARE-driven genes were in the Nrf1 cKO mice with mice. Among we found that expression of metallothionein-1 and -2 genes is on Nrf1 not on Nrf2. reporter that Nrf1 preferentially activates the MT1 ARE. in livers from mutant mice Nrf2 activates its target genes any H. H. A. H. Yamamoto M. Biochem. Biophys. Res. Commun. 2006; PubMed Scopus Google Scholar), induction of MT1 expression was These thus, that Nrf1 has acquired specific distinct from of the CNC family of the Nrf1 Nrf1 DNA was from a the Nrf1 gene from the at a Nrf1 targeting to a of a into the Nrf1 and a of protein was also into the at a of the was of the Nrf1 gene to we identified one that a The of with the was by analysis of and DNA a the targeting The and The were into and mice were with to mice. deletion of the Nrf1 was through with the mice from The The mice were with mice to mice, which were with each to hepatocyte-specific mice. of mice with Nrf2 mutant mice (4Itoh K. Chiba T. Takahashi S. Ishii T. Igarashi K. Katoh Y. Oyake T. Hayashi N. Satoh K. Hatayama I. Yamamoto M. Nabeshima Y. Biochem. Biophys. Res. Commun. 1997; 236: 313-322Crossref PubMed Scopus (3088) Google Scholar) or mutant mice H. H. A. H. Yamamoto M. Biochem. Biophys. Res. Commun. 2006; PubMed Scopus Google Scholar), mice or mice were These were to the compound mutant and and was from livers of three mice and mice and was in that were to by the for Nrf1 were as and specific to have been K. H. Katsuoka F. Engel J.D. Yamamoto M. J. Biol. Chem. 1999; 274: Full Text Full Text PDF PubMed Scopus Google Scholar). was an or as reported N. Takahashi S. T. Yamamoto M. 1998; PubMed Google Scholar). The and sequences used to NAD(P)H dehydrogenase quinone the glutamate-cysteine ligase catalytic heme and glutathione S-transferase have been F. H. Ishii T. H. Engel J.D. Yamamoto M. Mol. Cell. Biol. 2005; PubMed Scopus Google Scholar, T. H. Takahashi S. S. Yamamoto M. J. Biol. Chem. 2008; Full Text Full Text PDF PubMed Scopus Google Scholar). Nrf1, and were the and MT1 MT1 MT1 The and were from were being and to the for the Gene were to the were with and in were and with and To livers were with and in The were with and with was by at and or at and were with an T. M. T. T. Engel J.D. H. Yamamoto M. Genes 2006; PubMed Scopus Google Scholar), and M. Yamamoto T. H. T. T. T. Engel J.D. B. Yamamoto M. Genes PubMed Scopus Google Scholar) were with at their and by The was with and with the To a of and and their mutant and were a of was to individual of the and proteins with or was as K. M. M. Mol. Cell. Biol. PubMed Google Scholar). the and were by on a in MT1 gene with its from K. of D. G.K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar) was into the reporter the ARE was generated by sequences to to the transcriptional from the reporter Nrf1 was into Nrf1 its ER (14Wang W. Chan J.Y. J. Biol. Chem. 2006; 281: 19676-19687Abstract Full Text Full Text PDF PubMed Scopus (131) Google were with or with or or of each and the to the of the were for the expression of and was a reporter was to for of J.D. Res. PubMed Scopus Google Scholar) from that been with or were to analysis as were with To were and with was were by of Nrf1 the in functions of Nrf1, we generated conditional Nrf1 mutant mice the targeting was in which the of was with sequences Because this the bZip DNA binding we that the a of Nrf1 that was of binding DNA and gene also an protein in the of Nrf1 that its expression be by protein. the targeting and the Nrf1 in by DNA was to a to the of the Nrf1 gene. was identified by the of an DNA by the of a in the of the element. mice were by into and the resulting were with mice to of the Nrf1 In mice were with mice, which and embryonic by not with a previous Nrf1 gene knock-out analysis (7Chan J.Y. Kwong M. Lu R. Chang J. Wang B. Yen T.S.B. Kan Y.W. EMBO J. 1998; 17: 1779-1787Crossref PubMed Scopus (214) Google Scholar). also that of into the did not the expression of Nrf1 in livers of mice Nrf1 a hepatocyte-specific deletion of Nrf1 in mice, we mice with mice, mice. of the and with liver DNA are shown in The of the to be and analysis revealed that Nrf1 were severely in livers of mutant mice of liver from mutant mice with and revealed that they many To the we also with The that the of mice a of when with mice. In of mice at of and in mice were in mice These the previous that knock-out of Nrf1 gene causes in the liver that human (10Xu Z. Chen L. Leung L. Yen T.S.B. Lee C. Chan J.Y. Proc. Natl. Acad. Sci. U. S. A. 2005; 102: 4120-4125Crossref PubMed Scopus (225) Google Scholar). of Genes in in a Nrf2-dependent of from livers of mice livers from as Because it has been reported that Nrf1 contributes to the expression of enzyme genes that are known to be by Nrf2, we whether the expression of Nrf2 target genes was in The revealed that the expression of a of genes is decreased in the absence of Nrf1 of Nrf1 on expression of Nrf2-dependent of quinone catalytic in a To these we four ARE-dependent genes GSTP1, GCLC, and and found that the expression of these genes was in livers when with livers Thus, in up-regulation of at least genes. To examine whether the expression of these genes on Nrf2, we generated a compound mutant bearing a deletion of Nrf2 with hepatocyte-specific deletion of The in expression of these four Nrf2 target genes was completely in the Nrf1:Nrf2 compound knock-out liver. This that the expression of antioxidant and xenobiotic-metabolizing enzyme genes is in an Nrf2-dependent in response to stress caused by the of An observation is that Nrf1 not contribute to the expression of these four genes in the absence of Nrf2, suggesting at least Nrf1 not contribute to the regulation of Nrf2 target genes of Genes in the we genes that were in the found that genes were decreased in the livers when with the categorized these genes into groups to their function To three of the genes be categorized as to the and family member the we found that many of the genes that were in Nrf1-null livers to the of This of genes proteins, a and These thus, that Nrf1 is in the regulation of a number of biological functions in the which are distinct from of expression were decreased in mice with and family member dehydrogenase protein protein member domain and and gene protein factor protein family protein and protein protein domain domain family member domain protein domain domain factor in a Genes in the genes identified in the MT1 and have been reported to contain at least one ARE in their regulatory regions D. G.K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). To these we and that the expression of MT1 and genes was in livers when with their expression in mice It is well known that the expression of is in response to and that this is by the transcription factor through the response element in gene F. R. M. M. Z. W. EMBO J. PubMed Scopus Google Scholar). that expression did not in the livers not indicating that the of MT1 in the livers was not caused by of Because the ARE-dependent genes were in mice in an Nrf2-dependent these the that in liver the MT1 and genes are preferentially and by Nrf1, not by Nrf2, through the ARE in their regulatory MT1 ARE by Nrf1 by of the MT1 gene has been with to transcription factor and its binding to the response element sequence F. R. M. M. Z. W. EMBO J. PubMed Scopus Google Scholar). In addition to this response it has been reported that the MT1 gene has a conserved ARE in its regulatory G.K. Biochem. PubMed Scopus Google Scholar). also that are in the regions of vertebrate genes, as from and contribution of the CNC family factors to the regulation of MT1 expression has not been well To examine whether Nrf1 and Nrf2 bind to the MT1 ARE, we For this Nrf1, Nrf2, and proteins their DNA binding domains and were in a expression found that and heterodimers bind to the MT1 ARE with The binding was specific it was by of an ARE not by a mutant ARE that Nrf1 and Nrf2 exhibit binding for the MT1 ARE. the that Nrf1 and Nrf2 transcription through the MT1 ARE. a reporter The MT1 gene regulatory the ARE was to a and the reporter was into with or expression Although the of and was found to be comparable the MT1 reporter gene was activated by was activated by and were severely when the MT1 ARE sequence was from the reporter that is on the ARE. In stark contrast, activated a reporter gene by ARE did These thus, that the MT1 gene is an ARE-dependent gene by Nrf1 not by Nrf2. MT1 by of Nrf2 in that Nrf2 not regulate we whether or not MT1 is in the livers of mutant mice Nrf2 can its target genes. Nrf2 target genes were in mice, as has been reported H. H. A. H. Yamamoto M. Biochem. Biophys. Res. Commun. 2006; PubMed Scopus Google Scholar). was in the MT1 gene expression and mice, that the MT1 gene is not by Nrf2 in Because Nrf1 and Nrf2 show binding and expression these factors have been to overlapping target genes and overlapping (1Motohashi H. O'Connor T. Katsuoka F. Engel J.D. Yamamoto M. Gene (Amst.). 2002; 294: 1-12Crossref PubMed Scopus (377) Google Scholar, 2Blank V. J. Mol. Biol. 2008; 376: 913-925Crossref PubMed Scopus (114) Google Scholar). in mice revealed that Nrf1-null mice (7Chan J.Y. Kwong M. Lu R. Chang J. Wang B. Yen T.S.B. Kan Y.W. EMBO J. 1998; 17: 1779-1787Crossref PubMed Scopus (214) Google Scholar) exhibit a from that of the Nrf2-null mice (4Itoh K. Chiba T. Takahashi S. Ishii T. Igarashi K. Katoh Y. Oyake T. Hayashi N. Satoh K. Hatayama I. Yamamoto M. Nabeshima Y. Biochem. Biophys. Res. Commun. 1997; 236: 313-322Crossref PubMed Scopus (3088) Google Scholar), suggesting that these transcription factors distinct the analysis of Nrf1 has been knock-out of the Nrf1 gene in mice embryonic to specific that Nrf1 we have a of its function in this we generated hepatocyte-specific Nrf1 gene knock-out mice and the and in the livers of the mutant mice. revealed that loss of Nrf1 did not in the of well known genes, genes were in Nrf1 cKO mice. Furthermore, we found that Nrf1 stress response genes, as and DNA genes as well as genes in and the of These thus, that Nrf1 has acquired unique functions that cannot be by the CNC family transcription factors during its molecular evolution. An during the study was that expression of genes were in mice when with their expression in mice. This induction is on Nrf2 as the induction of these genes in mice was deletion of Nrf2. that in the absence of Nrf1, Nrf2 can be activated by It is well known that Nrf2 is activated by and ER C. K. M. Yamamoto M. S. Biochem. Biophys. Res. Commun. 2006; PubMed Scopus Google Scholar, B. Yamamoto M. J. 2007; PubMed Scopus Google Scholar, D. M. E. Mol. Cell. Biol. 2003; 23: PubMed Scopus Google Scholar). a is that the disruption of Nrf1 ER which to the of Nrf2 (13Zhang Y. Lucocq J.M. Yamamoto M. Hayes J.D. Biochem. J. 2007; 408: 161-172Crossref PubMed Scopus (30) Google Scholar, W. Chan J.Y. J. Biol. Chem. 2006; 281: 19676-19687Abstract Full Text Full Text PDF PubMed Scopus (131) Google Scholar). with the that Nrf2, we that Nrf2 target genes are in liver specific knock-out of T. H. Takahashi S. S. Yamamoto M. J. Biol. Chem. 2008; Full Text Full Text PDF PubMed Scopus Google Scholar). In this during into a number of antioxidant glutathione and T. H. Takahashi S. S. Yamamoto M. J. Biol. Chem. 2008; Full Text Full Text PDF PubMed Scopus Google Scholar). These show that the Nrf2 gene battery a of that to with stress that is of an Thus, Nrf2 is for severe stress In contrast, Nrf1 is indispensable for stress and the of Nrf1 activates Nrf2 as a the that are by the of CNC members has on the and they In the livers of Nrf1 knock-out mice, of the genes to the are MT1 and are MT1 and genes have been reported to at least one ARE in their These have also been reported to the regulation by bZip proteins and G.K. Res. 2003; PubMed Scopus Google Scholar) and Nrf2 Yen 2005; PubMed Scopus Google Scholar). In contrast, of reported that MT1 expression was not decreased in the livers of Nrf2 knock-out mice N. Itoh K. H. Yamamoto M. J. Biol. Chem. 2003; 278: Full Text Full Text PDF PubMed Scopus Google Scholar). In with the we found that in the livers of mice, MT1 gene expression is not in response to the of Nrf2. The analysis revealed that in the absence of Nrf1, MT1 and are Nrf2 target genes are in an Nrf2-dependent These that MT1 and genes are activated by The reporter that Nrf1 and Nrf2 regulate members of the ARE gene Nrf2 not Nrf1 activates the reporter gene Nrf1 not Nrf2 activates reporter gene expression through the MT1 ARE. In contrast, however, that Maf and Maf heterodimers bind to the MT1 ARE with DNA binding not to be to account for their target gene that Nrf1 and Nrf2 bind the MT1 ARE, Nrf1 can a that activates transcription of the MT1 gene. in to the of the DNA binding and the domain is not conserved Nrf1 and Nrf2. Thus, analysis of the of Nrf1 and Nrf2 as a to this and and G.K. Biochem. PubMed Scopus Google Scholar). For instance, knock-out of the MT1 gene mice to liver damage by Z. J. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). Furthermore, MT1 and mutant mice have a to from and although they show was in these mutant mice J.H. I. Proc. Natl. Acad. Sci. U. S. A. 1998; PubMed Scopus Google Scholar). a and regulation of is Nrf1 target genes responsible for the of to be for ARE sequences within the of genes in as many functional have been found in the found genes that have ARE sequences in the have not been reported to be among these genes, dehydrogenase is by E. R. I. 2003; PubMed Scopus (377) Google Scholar). is a regulatory enzyme in the of from to in response to K. Biochem. J. 2002; PubMed Scopus Google Scholar, J. 2003; PubMed Scopus Google Scholar). The expression of was comparable in mice with the of expression in mice not also found that genes, as protein and and stress response gene one or in their Although it to be whether is a the of these genes and the NASH-like liver damage in mice, this to an to of we have generated hepatocyte-specific Nrf1 knock-out mice from the of Chan and (10Xu Z. Chen L. Leung L. Yen T.S.B. Lee C. Chan J.Y. Proc. Natl. Acad. Sci. U. S. A. 2005; 102: 4120-4125Crossref PubMed Scopus (225) Google Scholar). have found that the NASH-like liver pathology and in the mutant mice are in with the previous gene expression has not been reported in Nrf1 knock-out mice. Furthermore, among the genes we found a differences in the hepatocyte-specific Nrf1 knock-out mice. that this be due to a or it be due to In we have that Nrf1 contributes to the expression of a of ARE-dependent genes that is distinct from by Nrf2, indicating that each CNC family member has acquired a specific target gene of the individual function of CNC members into the regulation of the ARE gene the of Y. for the H. for and and members for with