关键词： ATF3   congenital anomaly   endocrine disruptor   hypospadias   steroid  

摘要： The molecular events that lead to isolated hypospadias remain largely unknown, and the etiology of this common congenital anomaly seems to be multifactorial. We have explored the response of several candidate genes to environmental agents that cause hypospadias in a mouse model. Here, we provide an overview of current findings in relation to candidate genes and their response to environmental agents, including the results of genomic analyses of both mouse and human tissues. In addition to steroid-hormone receptors, one gene of specific interest is activating transcription factor 3 (ATF3). We hypothesize a potential mechanism of action for ATF3 and other identified genes, including TGF-B.

关键词： 转录激活因子3   转录调控   细胞凋亡  

摘要： 转录激活因子3(activating transcription factor3,ATF3)属含亮氨酸拉链结构的转录因子ATF/CREB家族成员,分子量21ku,在大部分正常细胞中呈低浓度稳态表达。ATF3是个应激早期快反应基因,体内外可被一系列损伤性应激信号快速诱导表达。ATF3不仅在应激反应中是个关键性的调控因子,还广泛参与了机体稳态维持、创伤愈合、细胞黏附、肿瘤形成、凋亡以及信号传导等生理和病理过程。ATF3与细胞生存和凋亡有关,但在不同的细胞状态下发挥不同甚至相反的作用。

关键词： lipopolysaccharide   chemokine   gene expression   MIP-1 beta   inflammation  

摘要： Acute expression of macrophage inflammatory protein-1 beta (also known as CCL4) promotes beneficial leukocyte recruitment to infected tissues, but chronic expression of this chemokine contributes to inflammatory disease. CCL4 expression is controlled largely at the transcriptional level and an ATF/CRE sequence located in the promoter (-104 to -97 bp, relative to the transcriptional start site) has been identified as a critical cis-acting element. The trans-acting binding proteins that influence CCL4 transcription via this site are largely unknown. We investigated whether activating transcription factor 3 (ATF3), a member of the ATF/CREB family of transcription factors, binds to the CCL4 ATF/CRE site in macrophages. Using the electrophoretic mobility shift assay and the chromatin immunoprecipitation assay, we found that ATF3 binds to the ATF/CRE site within the CCL4 promoter in untreated and lipopolysaccharide (LPS)-stimulated macrophages. Quantitative RT-PCR analysis showed that CCL4 mRNA levels in elicited peritoneal macrophages from ATF3(-/-) mice are significantly higher than in congenic ATF3(+/+) macrophages under both unstimulated and LPS-stimulated conditions, suggesting that ATF3 represses transcription of the CCL4 gene. Consistent with the higher gene expression, ATF3-deficient macrophages secreted more CCL4 protein than ATF(+/+) macrophages. Similar results were obtained in bone-marrow-derived macrophages treated with Toll-like receptor 2, 3, 4 and 5 agonists. Thus, we conclude that ATF3 constitutively binds to the ATF/CRE site in the CCL4 promoter where it represses basal and pathogen-associated molecular pattern (PAMP)-stimulated transcription. Consequently, ATF3 appears to be part of a control mechanism that limits the amount of CCL4 released by macrophages, preventing excessive inflammation. (c) 2006 Elsevier Ltd. All rights reserved.

关键词： activating transcription factor 3 (ATF3)   mitogen activated protein kinase (MAPK)   MAPK kinase (MKK)   p38   stress kinase   stress response  

摘要： ATF3 (activating transcription factor 3) gene encodes a member of the ATF/CREB (cAMP-response-element-binding protein) family of transcription factors. Its expression is induced by a wide range of signals, including stress signals and signals that promote cell proliferation and motility. Thus the ATF3 gene can be characterized as an 'adaptive response' gene for the cells to cope with extra- and/or intra-cellular changes. In the present study, we demonstrate that the p38 signalling pathway is involved in the induction of ATF3 by stress signals. Ectopic expression of CA (constitutively active) MKK6 [MAPK (mitogen-activated protein kinase) kinase 6], a kinase upstream of p38, indicated that activation of the p38 pathway is sufficient to induce the expression of the ATF3 gene. Inhibition of the pathway indicated that the p38 pathway is necessary for various signals to induce ATF3, including anisomycin, IL-1 beta (interleukin 1 beta), TNF alpha (tumour necrosis factor alpha) and H2O2. Analysis of the endogenous ATF3 gene indicates that the regulation is at least in part at the transcription level. Specifically, CREB, a transcription factor known to be phosphorylated by p38, plays a role in this induction. Interestingly, the ERK (extracellular-signal-regulated kinase) and JNK (c-Jun N-terminal kinase)/SAPK (stress-activated protein kinase) signalling pathways are neither necessary nor sufficient to induce ATF3 in the anisomycin stress paradigm. Furthermore, analysis of caspase 3 activation indicated that knocking down ATF3 reduced the ability of MKK6(CA) to exert its pro-apoptotic effect. Taken together, our results indicate that a major signalling pathway, the p38 pathway, plays a critical role in the induction of ATF3 by stress signals, and that ATF3 is functionally important to mediate the pro-apoptotic effects of p38.

关键词： amino acid response element (AARE)   amino acid-sensing   activating transcription factor 3 (ATF3)   CCAAT/enhancer-binding protein (C/EBP)   histone acetylation   transcription regulation  

摘要： Expression of ATF3 (activating transcription factor 3) is induced by a variety of environmental stress conditions, including nutrient limitation. In the present study, we demonstrate that the increase in ATF3 mRNA content following amino acid limitation of human HepG2 hepatoma cells is dependent on transcriptional activation of the ATF3 gene, through a highly coordinated amino acid-responsive programme of transcription factor synthesis and action. Studies using transient overexpression and knockout fibroblasts showed that several ATF and C/EBP (CCAAT/enhancer-binding protein) family members contribute to ATF3 regulation. Promoter analysis showed that a C/EBP-ATF composite site at -23 to -15 bp relative to the transcription start site of the ATF3 gene functions as an AARE (amino acid response element). Chromatin immunoprecipitation demonstrated that amino acid limitation increased ATF4, ATF3, and C/EBP beta binding to the ATF3 promoter, but the kinetics of each was markedly different. Immediately following histidine removal, there was a rapid increase in histone H3 acetylation prior to an enhancement in ATF4 binding and in histone H4 acetylation. These latter changes closely paralleled the initial increase in RNA pol II (RNA polymerase II) binding to the promoter and in the transcription rate from the ATF3 gene. The increase in ATF3 and C/EBP beta binding was considerably slower and more closely correlated with a decline in transcription rate. A comparison of the recruitment patterns between ATF and C/EBP transcription factors and RNA polymerase II at the AARE of several amino acid-responsive genes revealed that a highly co-ordinated response programme controls the transcriptional activation of these genes following amino acid limitation.

关键词： 3D reconstruction   ATF3   BBB   NeuN   neuronal survival   p-c-Jun  

摘要： Studies of spinal cord injury using contusion (impact) injury paradigms have shown that neuronal death is an acute event that is largely over within 24 h. However, much less is known about cell death following compression injury, despite compression being a key component of natural spinal injuries. We have therefore used neuronal nuclei (NeuN) immunostaining to examine the spatiotemporal pattern of neuronal loss after static compression injury in adult rats. 3D reconstruction was used to reveal the full effect of the injury. Neuronal loss at the injury epicentre, assessed by NeuN immunostaining, amounted to 44% at 1 day but increased to 73% at 3 days and 81% at 1 month. Neuronal loss was also seen 5 mm rostral and caudal to the epicentre, but was not significant until 3 days. NeuN loss was greatest in the ventral horns and in the intermediate grey matter, with the lateral dorsal horns relatively spared. Cystic cavities formed after injury, but were not evident until 4 weeks and were small in size. In contrast to the slow profile of neuronal loss, the compression injury also evoked a transient expression of activating transcription factor-3 (ATF3) and activated c-Jun in neurons. ATF3 expression peaked at 3 days and declined at 7 days. Our spatiotemporal analysis of compression injury shows that neuronal loss is much more protracted than in contusion injury, and highlights the potential for neuroprotective strategies. This study is also the first indication of ATF3 involvement in spinal cord injury.

关键词： ATF3   hypoxia   anoxia   HIF   p53   MKK7/JNK  

摘要： Solid tumors often have an inadequate blood supply, which results in large regions that are subjected to hypoxic or anoxic stress. Hypoxia-inducible factor-1 (HIF-1) is a transcription factor that regulates much of the transcriptional response of cells to hypoxia. Activating transcription factor 3 (ATF3) is another transcription factor that responds to a variety of stresses and is often upregulated in cancer. We investigated the regulation of ATF3 by oxygen deprivation. ATF3 induction occurred most robustly under anoxia, is common, and it is not dependent on presence of HIF-1 or p53, but is sensitive to the inhibition of c-Jun NH2-terminal kinase activation and the antioxidant N-acetylcystein. ATF3 could also be induced by desferrioxamine but not by the mitochondrial poison cyanide or the nonspecific 2-oxoglutarate dioxygenase inhibitor dimethyloxalylglycine. We also show that anoxic ATF3 mRNA is more stable than normoxic mRNA providing a mechanism for this induction. Thus, this study demonstrates that the regulation of ATF3 under anoxia is independent of 2-oxoglutarate dioxygenase, HIF-1 and p53, presumably involving multiple regulatory pathways.

关键词： 前列腺癌   激活转录因子3   免疫组织化学   Western Blot  

摘要： 目的：检测激活转录因子3(ATF3)在正常前列腺、前列腺增生和前列腺癌组织中的表达情况，初步探讨ATF3在前列腺癌的发生、发展、转移中的作用，并分析ATF3表达与前列腺癌临床病理特征的关系。 方法：采用免疫组织化学S-P法和Western Blot检测正常前列腺、良性前列腺增生及前列腺癌组织中ATF3的表达，对比其表达的差异，并分析其表达水平与前列腺癌临床病理参数的关系。 结果：免疫组化显示：ATF3在正常前列腺组织中无阳性表达，良性前列腺增生组织中阳性表达率为13.04％，在前列腺癌组织中阳性表达率为58.70％，ATF3在前列腺癌组织中的表达明显高于正常前列腺组织和良性前列腺增生组织(P＜0.01)。在不同病理分级前列腺癌组织中，高分化组ATF3的表达明显低于于中分化组和低分化组(P＜0.05)，中分化组ATF3的表达明显低于低分化组(P＜0.05)。ATF3在Whitmore-Jewett分期C+D期组的表达明显高于A+B组(P＜0.05)。ATF3在转移性前列腺癌组织中的表达明显高于无转移组(P＜0.05)。ATF3在前列腺癌组织中的表达与术前PSA水平无相关性。Western Blot结果显示：ATF3在前列腺癌组织中的表达较正常前列腺组织和前列腺增生组织高(P＜0.05)。 结论：ATF3在前列腺癌组织的表达高于正常前列腺组织和良性前列腺增生组织。ATF3的表达与临床分期、病理分级、是否伴有转移有关。ATF3表达与术前血清PSA水平无相关性。ATF3可能与前列腺癌的发生、发展、侵袭和转移有关。ATF3可以作为预测前列腺癌的恶性程度和预后的指标。进一步研究前列腺癌中ATF3产生的分子机制和ATF3相关的信号传导通路，有可能揭示前列腺癌的发生机制。

关键词： end-to-side repair   transcription factor   ATF3   cell activation   nerve injury  

摘要： We wanted to find out if any of three different types of manipulations: a piece of muscle or nerve put parallel to a nerve;an epineurial window made, or sutures inserted into a nerve, or both;or pieces of nerve sutured to an epineurial window end-to-side to the musculocutaneous or sciatic nerve, resulted in activation of activating transcription factor 3 ( ATF3) in neurons and in non-neuronal cells. ATF3, a marker of cell activation, was investigated by immunocytochemistry one week after manipulation. A piece of nerve or muscle parallel to a nerve did not induce ATF3 locally in the nerve and induced ATF3 only rarely in neurons. In contrast, an epineurial window or insertion of sutures, or both, with or without attachment of a piece of nerve placed end-to-side, induced robust ATF3 expression. We conclude that an injury to a peripheral nerve trunk associated with end-to-side nerve repair, activates neurons and non-neuronal cells and may contribute to sprouting of axons into the nerve attached end-to-side.