Faculty Bibliography

Up-regulation of the c-jun gene is a critical event in the retinoic acid (RA)-mediated differentiation of embryonal carcinoma F9 cells. Activation transcription factor-2 (ATF-2), adenovirus E1A associated p300 protein (p300) and Jun dimerization protein (JDP2) cooperate in the regulation of transcription of the c-jun gene. ATF-2 was found to be a novel histone acetyltransferase (HAT) and it acetylated specifically both histone H2B and histone H4. Motif A, of the HAT domain, was responsible for stimulation of the transcription of c-jun gene, in conjunction with HAT of p300. By contrast, JDP2 served as a repressor of AP-1 and inhibited the transactivation of the c-jun gene by p300/ATF-2, by recruitment of histone deacetylase complex (HDAC3), thereby repressing the RA-induced transcription of the c-jun gene and then inhibiting the RA-mediated differentiation of F9 cells. These results suggest that HDAC3/JDP2 and p300/ATF-2 complex play a critical role in controlling the differentiation of F9 cells, in response to RA. $$:

Up-regulation of the c-jun gene is a critical event in the retinoic acid (RA)-mediated differentiation of embryonal carcinoma F9 cells. Activating transcription factor 2 (ATF-2) and p300 cooperate in the activation of transcription of the c-jun gene during the differentiation of F9 cells. We show here that the overexpression of Jun dimerization protein 2 (JDP2), a repressor of AP-1, inhibits the transactivation of the c-jun gene by ATF-2 and p300 by recruitment of the histone deacetylase 3 (HDAC3) complex, thereby repressing the RA-induced transcription of the c-jun gene and inhibiting the RA-mediated differentiation of F9 cells. Moreover, chromatin immunoprecipitation assays showed that the JDP2/HDAC3 complex, which binds to the differentiation response element within the c-jun promoter in undifferentiated F9 cells, was replaced by the p300 complex in response to RA, with an accompanying change in the histone acetylation status of the chromatin, the initiation of transcription of the c-jun gene, and the subsequent differentiation of F9 cells. These results suggest that JDP2 may be a key factor that controls the commitment of F9 cells to differentiation and shed new light on the mechanism by which an AP-1 repressor functions

ATF-2 and p300 cooperate in the activation of transcription of the c-jun gene during the differentiation of F9 cells. We show here that a repressor of AP-1, JDP2 (Jun dimerization protein 2), inhibits the transactivation of the c-jun gene by ATF-2 and p300, by recruitment of a histone deacetylase complex, thereby repressing the retinoic acid (RA)-induced transcription of the c-jun gene and inhibiting the RA-mediated differentiation of F9 cells. Furthermore, JDP2/HDAC complex was replaced by p300 complex on the DRE (differentiation response element) of the c-jun promoter within 24 h after the start of exposure of cells to RA, with an accompanying change in the histone-acetylation status of the chromatin, indicating that the initiation of transcription of the c-jun gene was controled by sequential action of HDAC(s) and HAT(s) on c-jun promoter

A mouse cDNA that encodes a DNA-binding protein was identified by yeast two-hybrid screening, using activating transcription factor-2 (ATF-2) as the bait. The protein contained a bZIP (basic amino acid-leucine zipper region) domain and its amino acid sequence was almost identical to that of rat Jun dimerization protein 2 (JDP2). Mouse JDP2 interacted with ATF-2 both in vitro and in vivo via its bZIP domain. It was encoded by a single gene and various transcripts were expressed in all tested tissues of adult mice, as well as in embryos, albeit at different levels in various tissues. Furthermore, mouse JDP2 bound to the cAMP-response element (CRE) as a homodimer or as a heterodimer with ATF-2, and repressed CRE-dependent transcription that was mediated by ATF-2. JDP2 was identified as a novel repressor protein that affects ATF-2-mediated transcription

Rat pheochromocytoma PC12 cells undergo neuronal differentiation in response to nerve growth factor (NGF). The differentiation involves protein kinase cascades that include the kinases MEK and ERK, as well as activation of the transcription factors c-Jun and c-Fos. We show here, that exposure of PC12 cells to mannosylerythritol lipid (MEL), a yeast extracellular glycolipid, enhances the activity of acetylcholinesterase and interrupts the cell cycle at the G1 phase, with resulting outgrowth of neurites and partial cellular differentiation. Treatment with MEL stimulates the phosphorylation of ERK to a similar extent as treatment with NGF, although, the appearance of phosphorylated ERK is somewhat delayed. Both the MEL-induced outgrowth of neurites and the increase in the activity of acetylcholinesterase are prevented by PD98059, a specific inhibitor of MEK. Northern blotting analysis of c-jun transcripts and analysis of transcription in PC12 cells of a c-jun/CAT reporter construct demonstrated a significant increase in the rate of transcription of the c-jun gene upon treatment with MEL. The sequence elements required for the MEL-mediated activation of transcription of the c-jun gene are located between nucleotides -126 and -79 in the 5' flanking region. Our results suggest that MEL induces characteristics of neuronal differentiation in PC12 cells, with transactivation of the c-jun gene, via an ERK-related signal cascade that is partially overlapping the pathways activated in response to NGF. These results might provide the groundwork for the use of microbial extracellular glycolipids as novel reagents for the treatment of cancer cells

Interferon gamma (IFN gamma) is an important immunoreguratory protein and is secreted from CD4+, CD8+ T cells and NK cells. Expression of IFN gamma gene is regulated by either DNA-methylation or cis-elements of transcriptional factors such as AP-1, NFAT, AP-4, YY-1, ATF and GATA. At a putative ATF binding site in a promoter region of IFN gamma gene, the position from -59 to -43, is important for the IFN gamma promoter activity. Our gel-shift competition studies demonstrated that addition of antibodies against ATF-2 caused super-shifts of DNA-protein complexes. In addition, it was clarified that p300 was involved in DNA-protein complexes by in vitro 'pull-down' experiments. Moreover, a co-expression of p300 and ATF-2 enhanced the promoter activity of IFN gamma gene. Thus, these results indicate that p300 and ATF-2 play critical rules in a basal transcription of IFN gamma gene in Jurkat T cells

Four analogs of succinoyl trehalose lipid-3 (STL-3)with saturated even-number or odd-number carbonchains, and unsaturated or halogenated fatty acidswere examined for their ability to inhibit the growthand induce the differentiation of HL-60 humanpromyelocytic leukemia cells. The optimalconcentration of STL-3 at which such activities wererecognized was closed to the critical micelleconcentration of STL-3. Analog of STL-3 witheven-number or odd-number carbon chain and unsaturatedfatty acids strongly inhibited growth and induced thedifferentiation of HL-60 cells, as evaluated in termsof nitroblue tetrazilium-reducing activity and theappearance of the CD36 antigen. An analog of STL-3with halogenated fatty acids significantly inhibitedproliferation but only induced the differentiation ofHL-60 cells. Our results indicate that the effects ofSTL-3 and its analogs on HL-60 cells depend on thestructure of the hydrophobic moiety of STL-3

We report here that a microbial extracellular glycolipid,mannosylerythritol lipid (MEL), induces the outgrowth ofneurites from and enhances the activity of acetylcholinesterase(AChE) in PC12 pheochromocytoma cells. Furthermore, treatment ofPC12 cells with MEL increased levels of galactosylceramide(Galbeta1-1'Cer; GalCer). Exposure of PC12 cells to exogenous GalCer caused the dose-dependent outgrowth ofneurites. By contrast, treatment of PC12 cells with nerve growthfactor (NGF) did not increase the level of GalCer in the cells. The neurite-related morphological changes induced by GalCerdifferend from those induced by NGF, indicating differencesbetween the signal transduction pathways triggered by NGF and by GalCer