关键词： ATF3   c-jun   SCG10   transcription factor   axonal regeneration   thalamus   peripheral nerve implantation   thalamic reticular nucleus  

摘要： The expression of the transcription factor ATF3 in the brain was examined by immunohistochemistry during axonal regeneration induced by the implantation of pieces of peripheral nerve into the thalamus of adult rats. After 3 days, ATF3 immunoreactivity was present in many cells within approximately 500 mu m of the graft, In addition, ATF3-positive cell nuclei were found in the thalamic reticular nucleus (TRN) and medial geniculate nuclear complex (MGN), from which most regenerating axons originate. CNS cells with ATF3-positive nuclei were predominantly neurons and did not show signs of apoptosis. The number of ATF3-positive cells had declined by 7 days and further by 1 month after grafting when most ATF3-positive cells were found in the TRN and MGN. 14 days or more after grafting, some ATF3-positive nuclei were distorted and may have been apoptotic. In some experiments of 1 month duration, neurons which had regenerated axons to the distal ends of grafts were retrogradely labeled with DiAsp. ATF3-positive neurons in these animals were located in regions of the TRN and MGN containing retrogradely labeled neurons and the great majority were also labeled with DiAsp. SCG10 and c-Jun were found in neurons in the same regions as retrogradely labeled and ATF3-positive cells. Thus, ATF3 is transiently upregulated by injured CNS neurons, but prolonged expression is part of the pattern of gene expression associated with axonal regeneration. The co-expression of ATF3 with c-jun suggests that interactions between these transcription factors may be important for controlling the program of gene expression necessary for regeneration. (c) 2004 Elsevier Inc. All rights reserved.

关键词： nerve compression   nerve injury   transcription factor   ATF3   regeneration   tetanic muscle force   muscle  

摘要： Nuclear translocation of activating transcription factor 3 (ATF3), used as a marker for neuronal injury, was studied by immunocytochemistry in sensory neurons in dorsal root ganglia and locally along the sciatic nerve after severe chronic nerve compression in rats. In compressed nerves (application of a narrow silicone tube), ATF3 immunoreactivity was seen in the nucleus of sensory neurons and in Schwann cells below the compression at two and four weeks. Removal of the silicone tube (decompression) at two weeks did not affect the number of ATF3-positive cell nuclei in dorsal root ganglia. No ATF3 immunoreactivity was found in undamaged nerves on the other side. Functional variables (toe spreading and muscle force) were impaired at two weeks, with partial improvement at four weeks. Nerve compression induces nuclear translocation of ATF3, a transcription factor associated with survival and regeneration of sensory neurons. The response is related to duration of compression and partly correlated to function.

关键词： 13C   GDF-15   NAG-1   ATF3   p53 DIM   apoptosis  

摘要： Indole-3-carbinol (13C), present in cruciferous vegetables, and its major in vivo product 3,3'-diindolylmethane (DIM), have been reported to suppress cancer development. However, the responsible molecular mechanisms are not fully understood. Nonsteroidal anti-inflaminatory drug-activated gene-1 (NAG-1) is a TGF-beta superfamily gene associated with pro-apoptotic and anti-tumorigenic activities. The present study was performed to investigate whether 13C and DIM influence NAG-1 expression and to provide the potential molecular mechanism of their effects oil anti-tumorigenesis. The 13C repressed cell proliferation and induced NAG-1 expression in a concentration-dependent manner. In addition, DIM increased the expression of NAG-1 as well as activating transcription factor 3 (ATF3), and the induction of ATF3 was earlier than that of NAG-1. The DIM treatment increased luciferase activity of NAG-1 in HCT-116 cells transfected with NAG-1 promoter construct. The results suggest that 13C represses cell proliferation through up-regulation of NAG-1 and that ATF3 may play a pivotal role in DIM-induced NAG-1 expression ill human colorectal cancer cells. Furthermore, the mixture of 13C with resveratrol enhances NAG-1 expression, suggesting the synergistic effect of these two unrelated compounds on NAG-1 expression. (C) 2005 Elsevier Inc. All rights reserved.

关键词： TGF-beta   Smad   Nrf2   glutathione   ATF3   free radicals  

摘要： This study provides evidence that in mammary epithelial cells the pluripotent cytokine TGF-beta1 repressed expression of multiple gene, involved in Phase II detoxification. GCLC, the gene that encodes the catalytic subunit of the enzyme glutamate cysteine ligase, the rate-limiting enzyme in the biosynthesis of glutathione, was used as a molecular surrogate for investigating the mechanisms by which TGF-beta suppressed Phase II gene expression. TGF-beta was found to suppress luciferase reporter activity mediated by the human GCLC proximal promoter, as well as reporter activity mediated by the GCLC antioxidant response element, ARE4. TGF-beta downregulated expression of endogenous GCLC mRNA and GCLC protein. TGF-beta suppression of the Phase II genes correlated with a decrease in cellular glutathione and an increase in cellular reactive oxygen species. Ectopic expression of constitutively active Smad3E was sufficient to inhibit both reporters in the absence of TGF-beta, whereas dominant negative Smad3A blocked TGF-beta suppression. Smad3E suppressed Nrf2-mediated activation the GCLC reporter. We demonstrate that TGF-beta increased ATF3 protein levels, as did transient overexpresssion of Smad3E. Ectopic expression of ATF3 was sufficient to suppress the GCLC reporter activity, as well as endogenous GCLC expression. These results demonstrate that Smad3-ATF3 signaling mediates TGF-beta1 repression of ARE-dependent Phase II gene expression and potentially provide critical insight into mechanisms underlying TGF-beta1 function in carcinogenesis, tissue repair, and fibrosis. (C) 2004 Elsevier Inc. All rights reserved.

摘要： Currently there are 20 million people diagnosed with diabetes in the United States and the incidence is expected to increase by 42% over the next twenty years. Type 1, or insulin-dependent diabetes, is an autoimmune disorder characterized by infiltration of activated T-lymphocytes into the pancreas. Auto-reactive immune cells initiate β-cell destruction by several mechanisms including secretion of soluble factors (cytokines), direct cell-cell contact, and activation of osmotic lysis signals. Type 2, or insulin-independent diabetes, is characterized by insulin resistance in the peripheral tissues such as the liver, fat, and skeletal muscle. Phosphorylation of key substrates involved in the insulin signal transduction pathway by stress-activated protein kinases contributes to the insulin resistance and prevents the uptake of glucose from the blood. Recent reports suggest that type 2 diabetes is a slower progressing form of type 1 and that β-cell apoptosis contributes to the pathogenesis of both forms. Activating Transcription Factor 3 (ATF3) is a member of the ATF/CREB family of transcription factors which regulate gene expression through their ability to bind a common DNA sequence motif (TGACGTCA). Levels of endogenous ATF3 are extremely low in most tissues or cell types; however, ATF3 has been characterized as an immediate-early gene whose expression is up-regulated during the stress response. Prior to this work and during its undertaking several reports were published which describe the physiological outcomes of ATF3 expression during the stress response. These reports demonstrate a variety roles for ATF3 including protection from stress-induced apoptosis in neurons, promotion of apoptosis in endothelial cells, and enhancement of metastatic potential in colon cancer cells. In addition, transgenic mice which ectopically express ATF3 in endocrine precursor cells during development showed defects in pancreatic islet formation. Based on this information, we set out to

关键词： DRG neuron   axotomy   serpin   protease inhibitor   ATF3   plasminogen activator  

摘要： We have previously found that tissue type and urokinase type plasminogen activators (tPA and uPA) are induced in dorsal root ganglia (DRG) neurons after peripheral axotomy and that tPA plays crucial roles in generating neuropathic pain. Here we examined whether the plasminogen activator inhibitor-1 and -2 (PAI-1 and PAI-2) mRNA, endogenous inhibitors of tPA and uPA, are induced in the DRG following sciatic nerve transection. L4 and L5 DRG sections were examined using in situ hybridization histochemistry. The results showed that both PAI-1 and PAI-2 mRNA were up-regulated in DRG neurons within 1 day, and peaked at 1-3 days, after injury. Reduction of these mRNA was observed from 7 days after injury. The precise expression patterns of PAI-1 and PAI-2 mRNA at 3 days after axotomy revealed that PAI-1 mRNA was observed in predominantly small neurons, while much of the PAI-2 mRNA was expressed in large neurons. Double-labeling analysis of these mRNAs with activated transcription factor 3, known as an injury marker, revealed that most PAI-1 and PAI-2 mRNAs was induced in injured neurons. Co-expression of PAI-1, 2 with tPA and uPA in DRG neurons suggests that these inhibitors may act in an autocrine manner to modulate extracellular proteolytic activity after nerve injury. (c) 2005 IBRO. Published by Elsevier Ltd. All rights reserved.

关键词： DNA-BINDING PROTEINS   ETHYLENE-RESPONSIVE ELEMENT   INDUCED EXPRESSION   ARABIDOPSIS   PATHOGEN   PROMOTER   STRESS   ATF3   HOMEOSTASIS   REVEALS  

摘要： This study investigated the regulatory mechanism of rapid and transient induction of a transcriptional repressor ERF3 gene by wounding in tobacco ( Nicotiana tabacum) leaves. Deletion and mutation analysis of the promoter region have suggested that the proximal W boxes (TGAC(C/T)) and a GCC box, respectively, may be involved in the positive and negative regulation of wound-induced expression of the ERF3 gene. Electrophoretic mobility shift assays indicated that wounding enhanced the specific binding activity of nuclear factors to the W boxes. NtWRKY1, -2, and -4, which are tobacco group I WRKYs, interacted specifically with the W boxes and activated transcription via the W boxes. On the other hand, deletion of the GCC box from NsERF3 promoter-GUS reporter gene caused a delay in down-regulation of transcription after wound induction. In addition, ERF3 repressed transcription via the NsERF3 promoter activated by NtWRKYs. These results suggest the possible involvement of NtWRKYs and autorepression in the rapid and transient expression of the ERF3 gene by wounding.

关键词： DNA-Binding Proteins   Liver   Mitogens   Mitosis   Proto-Oncogene Proteinsc-myc   DNA  

摘要： Several agonists acting on G protein-coupled receptors (GPCR) enhance the mitogenic effect of epidermal growth factor (EGF) in rat hepatocytes, through mechanisms that have only partially been clarified. Results in various cells have led to the idea that a major mechanism for GPCR-mediated stimulation of cell growth is transactivation of receptor tyrosine kinases, particularly the EGF receptor (EGFR), leading to rapid phosphorylation of the EGFR and activation of downstream signaling pathways. In the present study cultured rat hepatocytes were exposed to various GPCR agonists, including vasopressin, angiotensin II (***), norepinephrine, or prostaglandin F-2alpha (PGF(2alpha)). None of these agents increased the phosphorylation of the EGFR or the docking protein Shc. Furthermore, we examined the effect of the GFCR agonists on the expression of two early response genes believed to be involved in growth activation. The GPCR agonists increased the mRNA expression of c-myc, and also of activating transcription factor 3 (ATF3)/liver regeneration factor-1 (LRF-1), which is a novel finding. Finally, the selective EGFR inhibitor AG1478 did not suppress the activation of extracellular signal-regulated kinase 112 (ERK1/2) or the induction of c-myc or ATF3/LRF-1 by the GPCR agonists, and did not prevent the comitogenic effects induced by these agents, while it blocked the effect of EGF on these responses. The results suggest that GPCR agonists induce expression of ATF3/LRF-1 and c-myc and exert comitogenic effects through mechanisms that do not require EGFR transactivation. (C) 2004 Wiley-Liss, Inc.

摘要： Hodgkin and Reed-Sternberg (HRS) cells display aberrant activity of several transcription factors, including nuclear factor kappa B (NF-kB) and members of the activator protein-1 (AP-1) family, that promote cytokine expression, cellular survival and proliferation. Using oligonucleotide microarrays, we set out to identify additional factors which are responsible for the malignant phenotype of HRS cells. Microarray analysis and subsequent Northern and Western blotting revealed that activating transcription factor 3 (ATF3), a member of the CREB/ATF family of transcription factors that is involved in the cellular response to stress signals, shows a strong constitutive expression in Hodgkin-derived cell lines. In contrast, ATF3 expression could not be detected in several Non-Hodgkin cell lines of distinct differentiation stages, ranging from pre-B cell lines to plasma B cell lines. To investigate the expression pattern of ATF3 in primary tumor cells, we performed immunohistochemistry on tissue microarrays. Immunohistochemistry confirmed a strong expression of ATF3 in primary HRS cells with a nuclear staining pattern. ATF3 expression was observed in almost all cases of classical Hodgkin lymphoma examined (69/71), whereas ATF3 expression was not detected in lymphocyte-predominant Hodgkin lymphoma. In addition, a significant number of anaplastic large cell lymphomas revealed a nuclear ATF3 staining pattern. In contrast, among all other B and T cell Non-Hodgkin lymphomas, ATF3 expression was observed only in rare cases (7/244), indicating that ATF3 expression is almost exclusively restricted to classical Hodgkin lymphoma and to a subset of anaplastic large cell lymphomas. To investigate the role of ATF3 for proliferation and survival of HRS cells, we generated vector-based siRNA constructs to downregulate ATF3 expression. Our vector system carries a puromycin-resistance gene thus allowing selection of siRNA expressing cells. Transfection of Hodgkin-derived cell lines with AT