1: J Biol Chem. 2003 May 23;278(21):19367-77. Epub 2003 Feb 21. Parkinsonian mimetics induce aspects of unfolded protein response in death of dopaminergic neurons. Holtz WA, O'Malley KL. Anatomy and Neurobiology Department, Washington University School of Medicine, St. Louis, Missouri 63110, USA. Genes associated with Parkinson's disease (PD) have suggested a role for ubiquitin-proteasome dysfunction and aberrant protein degradation in this disorder. Inasmuch as oxidative stress has also been implicated in PD, the present study examined transcriptional changes mediated by the Parkinsonism-inducing neurotoxins 6-hydroxydopamine (6-OHDA) and 1-methyl-4-phenylpyridinium (MPP+) in a dopaminergic cell line. Microarray analysis of RNA isolated from toxin treated samples revealed that the stress-induced transcription factor CHOP/Gadd153 was dramatically up-regulated by both 6-OHDA and MPP+. Treatment with 6-OHDA also induced a large number of genes involved in endoplasmic reticulum stress and unfolded protein response (UPR) such as ER chaperones and elements of the ubiquitin-proteasome system. Reverse transcription-PCR, Western blotting, and immunocytochemical approaches were used to quantify and temporally order the UPR pathways involved in neurotoxin-induced cell death. 6-OHDA, but not MPP+, significantly increased hallmarks of UPR such as BiP, c-Jun, and processed Xbp1 mRNA. Both toxins increased the phosphorylation of UPR proteins, PERK and eIF2 alpha, but only 6-OHDA increased phosphorylation of c-Jun. Thus, 6-OHDA is capable of triggering multiple pathways associated with UPR, whereas MPP+ exhibits a more restricted response. The involvement of UPR in these widely used neurotoxin models supports the role of ubiquitin-proteasome pathway dysfunction in PD. PMID: 12598533 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 2: J Biol Chem. 1996 Sep 13;271(37):22528-37. Multiple signaling pathways control the activation of the CEF-4/9E3 cytokine gene by pp60v-src. Bojovic B, Rodrigues N, Dehbi M, Bedard PA. Department of Biology, York University, North York, Ontario M3J 1P3, Canada. The CEF-4/9E3 cytokine gene is expressed aberrantly in chicken embryo fibroblasts (CEF) transformed by the Rous sarcoma virus. The expression of CEF-4 is dependent on both transcriptional and post-transcriptional mechanisms of regulation. The characterization of the promoter region indicated that three distinct regulatory elements corresponding to an AP-1 binding site (or TRE), a PRDII/kappaB domain, and a CAAT box are involved in the activation by pp60(v-)src. In this report we investigate the signaling pathways controlling the expression of the TRE and PRDII domain. The expression of a dominant negative mutant of p21(ras) reduced the activity of both elements. In contrast a similar mutant of c-Raf-1 affected modestly the activation dependent on the TRE but not PRDII. The stress-activated protein kinase (SAPK)/Jun N-terminal kinase (JNK) pathway was important for the activity of PRDII and the TRE but was not markedly stimulated by pp60(v-)src. The addition of calphostin C and the inhibition of protein kinase C (PKC) diminished the accumulation of the CEF-4 mRNA and reduced the activity of a TRE-controlled promoter. Likewise, the depletion of PKC by chronic treatment with phorbol esters inhibited the activation of the TRE. Rous sarcoma virus-transformed CEF treated with calphostin C were also flatter, did not display a high degree of criss-crossing, and appeared morphologically normal. Hence PKC was important for the activation of AP-1 and the morphological transformation of CEF. The constitutive expression of CEF-4 was correlated with transformation only when dependent on the TRE. This was not true for PRDII, which was the only element required for the constitutive activation to the CEF-4 promoter in nontransformed cells treated chronically with phorbol esters. PMID: 8798420 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 3: Kidney Int. 1996 Sep;50(3):894-901. Opposite, binary regulatory pathways involved in IL-1-mediated stromelysin gene expression in rat mesangial cells. Yokoo T, Kitamura M. Department of Medicine, University College London Medical School, Rayne Institute, England, United Kingdom. Glomerular mesangial cells express matrix metalloproteinase sromelysin in response to the proinflammatory cytokine IL-1 beta. The present study was conducted to identify intracellular machinery involved in this IL-1 action, especially focusing on the role of the TPA response element (TRE) located in the 5'-flanking region of the stromelysin gene. Using transient transfection with a pTRE-LacZ reporter plasmid, we detected no obvious up-regulation of TRE activity in rat mesangial cells following the IL-1 stimulation. However, the basal activity of TRE was found to be essential to the stromelysin induction, since (i) mesangial cells stably expressing a transdominant negative mutant of c-Jun, which effectively suppressed both basal and inducible TRE activity, exhibited the blunted expression of stromelysin in response to IL-1 beta, whereas (ii) transfection with a c-fos antisense gene, which suppressed only the inducible TRE activity, did not affect the stromelysin induction. To seek cooperative pathways required for the IL-1 action, we next focused on protein kinases, the potential regulators of the stromelysin gene. Stimulation of mesangial cells with a protein kinase C (PKC) activator, phorbol 12-myristate 13-acetate (PMA), induced the stromelysin transcript without affecting TRE activity. Depletion of intracellular PKC by high-dose PMA or inhibition of PKC activity with calphostin C suppressed the stromelysin induction by IL-1 beta, suggesting the crucial contribution of a PKC-mediated, but TRE-independent pathway. In contrast, either cAMP inducer forskolin or dibutyryl cAMP suppressed the IL-1-mediated stromelysin expression. An inhibitor of cAMP-dependent protein kinase A (PKA), HA1004, enhanced the IL-1 effect in a dose-dependent manner. Unexpectedly, the inhibitory action of PKA was not through cAMP response element (CRE) but through TRE, because (i) activation of CRE was not induced by IL-1 beta, and (ii) cAMP-mediated activation of PKA suppressed the basal TRE activity. These findings elucidated the unique, binary regulation of stromelysin by IL-1 beta; that is, IL-1 up-regulated the transcript via the PKC-dependent pathway under the cooperation with constitutively active TRE, and this stimulatory effect was in part counterbalanced by the IL-1-inducible PKA which down-regulated the basal TRE activity. PMID: 8872964 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 4: Genomics. 1996 Jul 1;35(1):227-30. Locations of human and mouse genes encoding the RFX1 and RFX2 transcription factor proteins. Doyle J, Hoffman S, Ucla C, Reith W, Mach B, Stubbs L. Biology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831-8077, USA. RFX transcription factors constitute a highly conserved family of site-specific DNA binding proteins involved in the expression of a variety of cellular and viral genes, including major histocompatibility complex class II genes and genes in human hepatitis B virus. Five members of the RFX gene family have been isolated from human and mouse, and all share a highly characteristic DNA binding domain that is distinct from other known DNA binding motifs. The human RFX1 and RFX2 genes have been assigned by in situ hybridization to chromosome 19p13.1 and 19p13.3, respectively. In this paper, we present data that localize RFX1 and RFX2 precisely within the detailed physical map of human chromosome 19 and genetic data that assign Rfx1 and Rfx2 to homologous regions of mouse chromosomes 8 and 17, respectively. These data define the established relationships between these homologous mouse and human regions in further detail and provide new tools for linking cloned genes to phenotypes in both species. PMID: 8661125 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 5: Oncogene. 1996 Jun 6;12(11):2301-8. Okadaic acid stimulated TRE binding activity in a papilloma producing mouse keratinocyte cell line involves increased AP-1 expression. Rosenberger SF, Bowden GT. Department of Radiation Oncology, The University of Arizona Health Sciences Center, Tucson 85724, USA. The effects of the non-phorbol ester type tumor promoter okadaic acid, a serine-threonine phosphatase inhibitor, on activator protein 1 (AP-1) DNA binding activity were studied in papilloma producing 308 mouse keratinocytes. Okadaic acid increased AP-1 binding to a consensus TPA responsive element (TRE) within 2 h; maximum stimulation was observed at 6 h followed by a gradual decrease to basal levels within 24 h. Jun B, Jun D and Fos B proteins were identified as the major components of the AP-1 complex binding to the TRE element at 6 h. Inhibition of transcription with actinomycin D and inhibition of protein synthesis with cycloheximide abrogated the okadaic acid effect on AP-1 DNA binding, indicating that transcription and translation are required for okadaic acid increased TRE binding activity. Northern and Western blot analyses revealed a correlation between increased AP-1 binding activity and accumulation of jun B, jun D and fos B mRNAs and proteins. These data suggest increased AP-1 expression as principal mechanism of okadaic acid stimulated AP-1 activation in the mouse keratinocytes studied. PMID: 8649769 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 6: Cell Immunol. 1995 Oct 1;165(1):92-100. Membrane immunoglobulin receptor cross-linking induces fosB mRNA expression in mature B lymphocytes: assembly of distinct FosB-containing nucleoprotein complexes during B cell stimulation. Dickinson JA, Amato SF, McManus BJ, Chiles TC. Department of Biology, Boston College, Chestnut Hill, Massachusetts 02167, USA. We demonstrate herein that anti-Ig stimulation of Bal-17 B cells leads to a rapid and transient increase in fosB mRNA levels, with kinetics similar to those previously reported for members of the jun gene family. The coupling of fosB expression to known protein kinases that are activated following membrane immunoglobulin receptor (mIg) cross-linking was evaluated. Inhibition of src-protein tyrosine kinase activity by pretreatment of Bal-17 B cells with herbimycin A prevented subsequent anti-Ig-dependent increases in fosB mRNA levels. Moreover, inhibition of protein kinase C (PKC) by pretreatment of Bal-17 B cells with staurosporine, H7, or by phorbol ester-induced down-regulation of PKC activity blocked anti-Ig-stimulated fosB gene expression. These findings suggest that fosB expression is coupled to a mIg-mediated pathway that utilizes activated src-protein tyrosine kinases and PKC. Immunoblotting of Bal-17 B cell extracts with anti-FosB antiserum revealed that mIg cross-linking results in an increase in FosB protein levels. Moreover, immunoprecipitation of nondenatured Bal-17 B cell extracts indicated that FosB forms complexes in vivo with JunB and JunD and to a lesser extent with cJun. The anti-Ig-induced FosB/Jun complexes bind to several distinct cis-acting DNA elements, including AP-1 and NF-AB, which have been implicated in regulating nuclear gene expression during B cell activation. Collectively, these results suggest that FosB plays a central role in regulating gene expression during anti-Ig-mediated B cell activation. PMID: 7671329 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 7: Oncogene. 1991 Apr;6(4):567-76. fosB is a transforming gene encoding a transcriptional activator. Schuermann M, Jooss K, Muller R. Institut fur Molekularbiologie und Tumorforschung (IMT) Philipps-Universitat Marburg, Federal Republic of Germany. The fosB gene encodes a nuclear protein that shows a high degree of homology with c-Fos in several of the known functionally crucial domains, e.g., the leucine zipper and the DNA-binding site, but shows considerable divergence in other regions. Here, we report that FosB, when placed under the control of a constitutive promoter, exhibits clear transforming properties in focus assays using mouse NIH3T3 or rat 208F fibroblasts. The transforming potential of FosB is considerably stronger than that of a corresponding c-fos construct and resembles that of viral fos genes. Using chimeric fos/fosB constructs we show that the C-terminal half of FosB is responsible for these stronger transforming properties, apparently by giving rise to significantly higher levels of protein as compared with the corresponding c-fos sequence. Surprisingly, substitution of the N-terminus of Fos with that of FosB decreases its transforming potential. These differences in the transforming potential are not related to DNA or protein expression, but rather seem to reflect differences in the molecular function(s) encoded in the N-terminal halves of Fos and FosB protein. Both, fosB- and v-fos transformed cells show increased expression of a number of endogenous genes, including c-jun, transin, alpha 1(III) collagen and tissue plasminogen activator. Transactivation by FosB and v-fos of the c-jun and alpha 1(III) collagen gene promoters and of a 3 x TRE-tk chimeric promoter could be shown in transient CAT assays. v-Fos, but not FosB-transformed cells, also show elevated levels of urokinase and plasminogen activator inhibitor mRNAs, pointing to potential differences in the gene regulatory properties of the two Fos family members. PMID: 1903195 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 8: EMBO J. 1990 Aug;9(8):2537-42. Multiple cDNA clones encoding nuclear proteins that bind to the tax-dependent enhancer of HTLV-1: all contain a leucine zipper structure and basic amino acid domain. Yoshimura T, Fujisawa J, Yoshida M. Department of Viral Oncology, Cancer Institute, Tokyo, Japan. A trans-activator protein, p40tax, of human T cell leukemia virus type 1 (HTLV-1) activates its own promoter and cellular promoters of IL-2, IL-2 receptor alpha and GM-CSF genes. We isolated three cDNA clones encoding cellular proteins that bind to the p40tax-dependent enhancer of HTLV-1 by screening a lambda gt11 cDNA library of an HTLV-1 infected cell line. All three proteins, TREB5, TREB7 and TREB36, contained a leucine zipper structure and basic amino acid domain, which are conserved in FOS, JUN and CREB, and also had multiple potential phosphorylation sites. The proteins expressed in Escherichia coli bound to the p40tax-dependent enhancer of the 21 bp sequence, but not to an inactive mutant carrying a mutation in the CRE region. In DNase I footprint analysis, all three proteins protected the 21 bp sequences in the LTR; however, the patterns were not identical to each other. TREB7 and TREB36 protected all three repeats of the 21 bp, but TREB5 protected only the second repeat. TREB7 and TREB36 protected the 5' and middle portions of the 21 bp which are essential for p40tax-mediated trans-activation, whereas TREB5 and CREB1 protected a narrower part of the middle region of the second 21 bp repeat containing the CRE consensus sequence. These structural features and DNA binding properties suggest that TREB proteins are members of a CREB protein family and that some of them (i.e., TREB7 and TREB36) may be involved in p40tax-mediated trans-activation. PMID: 2196176 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 9: Science. 1990 Mar 30;247(4950):1581-4. A new member of the leucine zipper class of proteins that binds to the HLA DR alpha promoter. Liou HC, Boothby MR, Finn PW, Davidon R, Nabavi N, Zeleznik-Le NJ, Ting JP, Glimcher LH. Department of Cancer Biology, Harvard School of Public Health, Boston, MA 02115. Several mutants derived from transformed human B cell lines are defective in expressing major histocompatibility complex (MHC) class II genes. The failure to express a class II gene in at least one such mutant line has been mapped to the MHC class II X box, a conserved transcriptional element in the promoter region. A complementary DNA encoding a DNA-binding protein (human X box binding protein, hXBP-1) whose target is the human DR alpha X box and the 3' flanking region has now been cloned. This complementary DNA encoded a protein with structural similarities to the c-jun proto-oncogene product, and its target sequence was closely related to the palindromic target sequence of c-jun. Mutation of the hXBP-1 DNA target sequence decreased DR alpha promoter activity in vivo. These studies suggest that the hXBP-1 protein acts as a transcription factor in B cells. PMID: 2321018 [PubMed - indexed for MEDLINE] ---------------------------------------------------------------