Characterization of a c-Jun-responsive module in the 5′-flank of the human CYP2J2 gene that regulates transactivation

Abstract

The human cytochrome P450 2J2 (CYP2J2) generates cytoprotective epoxyeicosatrienoic acids from arachidonic acid. Expression of CYP2J2 is decreased in hypoxia, and the resultant decrease in CYP2J2-derived epoxyeicosanoids may contribute to the pathogenesis of cardiac ischaemia. Recent studies have indicated that AP-1 (activator protein-1) regulates CYP2J2 expression in normoxia and hypoxia. Down-regulation of CYP2J2 in hypoxic HepG2 cells was closely associated with the up-regulation of c-fos and transient transfection analysis demonstrated that c-Fos abolishes the activation of CYP2J2 by the AP-1 protein c-Jun. Deletion of the region between nt -122 and -50 upstream of the start codon in CYP2J2 prevented c-Jun transactivation. In this study we demonstrate that the sequence at -105/-95 is a major regulatory element that binds c-Jun and has a prominent role in CYP2J2 gene transactivation. Mutagenesis of both the -105/-95 region and the previously identified element at -56/-63 was required for complete loss of transactivation by c-Jun; separate mutagenesis of the -105/-95 element or, to a lesser extent, the -56/-63 element resulted in a partial loss of gene activation. In contrast to the behaviour of the -56/-63 element, c-Jun homodimers and c-Fos/c-Jun heterodimers bound to the -105/-95 element. These findings demonstrate that the c-Jun-responsive module between -122 and -50 in the CYP2J2 proximal promoter contains an atypical AP-1 element at -105/-95 that has a major role in c-Jun transactivation and acts in conjunction with the -56/-63 element to regulate expression.

Up-Regulation of Human CYP2J2 in HepG2 Cells by Butylated Hydroxyanisole Is Mediated by c-Jun and Nrf2

“…c-Jun has been shown previously to activate the human CYP2J2 gene (Marden and Murray, 2005). Consistent with previous reports (Yu et al, 1997;Yuan et al, 2006), c-Jun and Nrf2 mRNAs were both increased in HepG2 cells by treatment with BHA (100 M) for 6 and 24 h (P Ͻ 0.05; Fig.…”

“…The CYP2J2-luciferase reporter constructs p2J2(Ϫ2341/ϩ98), p2J2(Ϫ1228/ϩ98), p2J2(Ϫ152/ϩ98), p2J2(Ϫ122/ϩ98), and p2J2(Ϫ82/ϩ98) were described previously (Marden et al, 2003;Marden and Murray, 2005). The construct p2J2(Ϫ152/ ϩ98; mtϪ105/Ϫ88), containing the mutagenized region Ϫ105/Ϫ88 was generated from p2J2(Ϫ152/ϩ98) using the QuikChange Site-Directed Mutagenesis Kit (Stratagene, Willoughby, NSW, Australia); oligonucleotide sequences are shown in Table 1.…”

“…The interplay between members of the activator protein-1 (AP-1) complex of leucine zipper (bZIP) transcription factors has been found to regulate basal CYP2J2 expression in human liverderived cells (Marden et al, 2003;Marden and Murray, 2005). Thus, c-Jun homodimers supported CYP2J2 expression in HepG2 cells cultured in a normoxic environment and activated CYP2J2-luciferase reporter constructs via AP-1-like gene elements in the CYP2J2 upstream region.…”

Variability of CYP2J2 Expression in Human Fetal Tissues

“…Recent investigations have suggested that upregulation of this enzyme, probably through a c-Jun-responsive module, promotes the neoplastic phenotype of carcinoma cells and may be involved in the pathogenesis of a variety of human cancers (Jiang et al, 2005;Marden and Murray, 2005). However, CYP2J2 can also metabolize a number of xenobiotics, including the antihistamine drugs ebastine (Hashizume et al, 2002) and astemizole (Matsumoto et al, 2002), contributing to their presystemic elimination in the small intestine.…”

Interaction of brain fatty acid-binding protein with the polyunsaturated fatty acid environment as a potential determinant of poor prognosis in malignant glioma

“…These combined data demonstrate a potentially important link between Notch1, Notch ligands and FABP7 in malignant glioma. This is important as Jagged-1 has previously been shown to play a role in the activation of the transcription factor Activator Protein 1 (AP-1), which in turn regulates the expression of proteins involved in AA and DHA metabolism such as cyclooxygenase-2 (COX-2) and cytochrome P450 2J2 (CYP2J2) [71][72][73][74]. Thus, Notch and/or its ligands may contribute to the deregulation of lipid metabolism in malignant glioma.…”