RESUMEN
Activating transcription factor 3 (ATF3) is a stress-responsive factor that belongs to the activator protein 1 (AP-1) family of transcription factors. ATF3 expression is stimulated by various factors such as hypoxia, cytokines, and chemotherapeutic and DNA damaging agents. Upon stimulation, ATF3 can form homodimers or heterodimers with other members of the AP-1 family to repress or activate transcription. Under physiological conditions, ATF3 expression is transient and plays a pivotal role in controlling the expression of cell-cycle regulators and tumor suppressor, DNA repair, and apoptosis genes. However, under pathological conditions such as those during breast cancer, a sustained and prolonged expression of ATF3 has been observed. In this review, the structure and function of ATF3, its posttranslational modifications (PTM), and its interacting proteins are discussed with a special emphasis on breast cancer metastasis.
Asunto(s)
Factor de Transcripción Activador 3/metabolismo , Neoplasias de la Mama/metabolismo , Regulación Neoplásica de la Expresión Génica , Proteínas de Neoplasias/metabolismo , Multimerización de Proteína , Procesamiento Proteico-Postraduccional , Factor de Transcripción Activador 3/química , Factor de Transcripción Activador 3/genética , Animales , Apoptosis , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Ciclo Celular , Reparación del ADN , Femenino , Humanos , Masculino , Metástasis de la Neoplasia , Proteínas de Neoplasias/genética , Relación Estructura-ActividadRESUMEN
Leptin acts via its receptor (LepRb) to modulate gene expression in hypothalamic LepRb-expressing neurons, thereby controlling energy balance and glucose homeostasis. Despite the importance of the control of gene expression in hypothalamic LepRb neurons for leptin action, the transcriptional targets of LepRb signaling have remained undefined because LepRb cells contribute a small fraction to the aggregate transcriptome of the brain regions in which they reside. We thus employed translating ribosome affinity purification followed by RNA sequencing to isolate and analyze mRNA from the hypothalamic LepRb neurons of wild-type or leptin-deficient (Lepob/ob) mice treated with vehicle or exogenous leptin. Although the expression of most of the genes encoding the neuropeptides commonly considered to represent the main targets of leptin action were altered only following chronic leptin deprivation, our analysis revealed other transcripts that were coordinately regulated by leptin under multiple treatment conditions. Among these, acute leptin treatment increased expression of the transcription factor Atf3 in LepRb neurons. Furthermore, ablation of Atf3 from LepRb neurons (Atf3LepRbKO mice) decreased leptin efficacy and promoted positive energy balance in mice. Thus, this analysis revealed the gene targets of leptin action, including Atf3, which represents a cellular mediator of leptin action.
Asunto(s)
Factor de Transcripción Activador 3/agonistas , Regulación de la Expresión Génica , Hipotálamo/metabolismo , Leptina/metabolismo , Neuronas/metabolismo , Receptores de Leptina/agonistas , Transducción de Señal , Factor de Transcripción Activador 3/química , Factor de Transcripción Activador 3/genética , Factor de Transcripción Activador 3/metabolismo , Animales , Cruzamientos Genéticos , Diabetes Mellitus/tratamiento farmacológico , Diabetes Mellitus/metabolismo , Diabetes Mellitus/patología , Metabolismo Energético/efectos de los fármacos , Femenino , Perfilación de la Expresión Génica , Regulación de la Expresión Génica/efectos de los fármacos , Hipoglucemiantes/farmacología , Hipoglucemiantes/uso terapéutico , Hipotálamo/citología , Hipotálamo/efectos de los fármacos , Hipotálamo/patología , Leptina/análogos & derivados , Leptina/farmacología , Leptina/uso terapéutico , Lipotrópicos/farmacología , Lipotrópicos/uso terapéutico , Masculino , Ratones Noqueados , Ratones Mutantes , Ratones Transgénicos , Proteínas del Tejido Nervioso/agonistas , Proteínas del Tejido Nervioso/química , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Neuronas/citología , Neuronas/efectos de los fármacos , Neuronas/patología , Obesidad/tratamiento farmacológico , Obesidad/metabolismo , Obesidad/patología , ARN Mensajero/química , ARN Mensajero/metabolismo , Receptores de Leptina/genética , Receptores de Leptina/metabolismo , Análisis de Secuencia de ARN , Transducción de Señal/efectos de los fármacosRESUMEN
Persistent DNA damage induces profound alterations in gene expression that, in turn, influence tissue homeostasis, tumorigenesis, and cancer treatment outcome. However, the underlying mechanism for gene expression reprogramming induced by persistent DNA damage remains poorly understood. Here, using a highly effective bioluminescence-based reporter system and other tools, we report that persistent DNA damage inhibits nonsense-mediated RNA decay (NMD), an RNA surveillance and gene-regulatory pathway, in noncycling cells. NMD suppression by persistent DNA damage required the activity of the p38α MAPK. Activating transcription factor 3 (ATF3), an NMD target and a key stress-inducible transcription factor, was stabilized in a p38α- and NMD-dependent manner following persistent DNA damage. Our results reveal a novel p38α-dependent pathway that regulates NMD activity in response to persistent DNA damage, which, in turn, controls ATF3 expression in affected cells.
Asunto(s)
Factor de Transcripción Activador 3/metabolismo , Daño del ADN , Regulación de la Expresión Génica , Proteína Quinasa 14 Activada por Mitógenos/metabolismo , Degradación de ARNm Mediada por Codón sin Sentido , ARN Mensajero/metabolismo , Factor de Transcripción Activador 3/química , Factor de Transcripción Activador 3/genética , Biomarcadores/metabolismo , Bleomicina/toxicidad , Células Cultivadas , Senescencia Celular , Activación Enzimática/efectos de los fármacos , Activación Enzimática/efectos de la radiación , Rayos gamma/efectos adversos , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/efectos de la radiación , Genes Reporteros/efectos de los fármacos , Genes Reporteros/efectos de la radiación , Células HEK293 , Humanos , Mediciones Luminiscentes , Proteína Quinasa 14 Activada por Mitógenos/antagonistas & inhibidores , Proteína Quinasa 14 Activada por Mitógenos/genética , Mutágenos/toxicidad , Degradación de ARNm Mediada por Codón sin Sentido/efectos de los fármacos , Degradación de ARNm Mediada por Codón sin Sentido/efectos de la radiación , Estrés Oxidativo , Estabilidad Proteica/efectos de los fármacos , Estabilidad Proteica/efectos de la radiación , Interferencia de ARN , Estabilidad del ARN/efectos de los fármacos , Estabilidad del ARN/efectos de la radiación , ARN Mensajero/químicaRESUMEN
Satellite cells are skeletal muscle stem cells that provide myonuclei for postnatal muscle growth, maintenance, and repair/regeneration in adults. Normally, satellite cells are mitotically quiescent, but they are activated in response to muscle injury, in which case they proliferate extensively and exhibit up-regulated expression of the transcription factor MyoD, a master regulator of myogenesis. MyoD forms a heterodimer with E proteins through their basic helix-loop-helix domain, binds to E boxes in the genome and thereby activates transcription at muscle-specific promoters. The central role of MyoD in muscle differentiation has increased interest in finding potential MyoD regulators. Here we identified transducin-like enhancer of split (TLE3), one of the Groucho/TLE family members, as a regulator of MyoD function during myogenesis. TLE3 was expressed in activated and proliferative satellite cells in which increased TLE3 levels suppressed myogenic differentiation, and, conversely, reduced TLE3 levels promoted myogenesis with a concomitant increase in proliferation. We found that, via its glutamine- and serine/proline-rich domains, TLE3 interferes with MyoD function by disrupting the association between the basic helix-loop-helix domain of MyoD and E proteins. Our findings indicate that TLE3 participates in skeletal muscle homeostasis by dampening satellite cell differentiation via repression of MyoD transcriptional activity.
Asunto(s)
Proteínas Co-Represoras/metabolismo , Regulación del Desarrollo de la Expresión Génica , Desarrollo de Músculos , Fibras Musculares Esqueléticas/metabolismo , Proteína MioD/antagonistas & inhibidores , Mioblastos/metabolismo , Células Satélite del Músculo Esquelético/metabolismo , Factor de Transcripción Activador 3/química , Factor de Transcripción Activador 3/genética , Factor de Transcripción Activador 3/metabolismo , Animales , Proliferación Celular , Células Cultivadas , Proteínas Co-Represoras/antagonistas & inhibidores , Proteínas Co-Represoras/química , Proteínas Co-Represoras/genética , Eliminación de Gen , Secuencias Hélice-Asa-Hélice , Masculino , Ratones , Ratones Endogámicos C57BL , Fibras Musculares Esqueléticas/citología , Proteína MioD/química , Proteína MioD/genética , Proteína MioD/metabolismo , Mioblastos/citología , Fragmentos de Péptidos/antagonistas & inhibidores , Fragmentos de Péptidos/química , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/metabolismo , Dominios y Motivos de Interacción de Proteínas , Multimerización de Proteína , Interferencia de ARN , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Células Satélite del Músculo Esquelético/citologíaRESUMEN
BACKGROUND: Dysregulation of the common stress responsive transcription factor ATF3 has been causally linked to many important human diseases such as cancer, atherosclerosis, infections, and hypospadias. Although it is believed that the ATF3 transcription activity is central to its cellular functions, how ATF3 regulates gene expression remains largely unknown. Here, we employed ATF3 wild-type and knockout isogenic cell lines to carry out the first comprehensive analysis of global ATF3-binding profiles in the human genome under basal and stressed (DNA damage) conditions. RESULTS: Although expressed at a low basal level, ATF3 was found to bind a large number of genomic sites that are often associated with genes involved in cellular stress responses. Interestingly, ATF3 appears to bind a large portion of genomic sites distal to transcription start sites and enriched with p300 and H3K27ac. Global gene expression profiling analysis indicates that genes proximal to these genomic sites were often regulated by ATF3. While DNA damage elicited by camptothecin dramatically altered the ATF3 binding profile, most of the genes regulated by ATF3 upon DNA damage were pre-bound by ATF3 before the stress. Moreover, we demonstrated that ATF3 was co-localized with the major stress responder p53 at genomic sites, thereby collaborating with p53 to regulate p53 target gene expression upon DNA damage. CONCLUSIONS: These results suggest that ATF3 likely bookmarks genomic sites and interacts with other transcription regulators to control gene expression.
Asunto(s)
Factor de Transcripción Activador 3/genética , Factor de Transcripción Activador 3/metabolismo , ADN/metabolismo , Histonas/metabolismo , Factores de Transcripción p300-CBP/metabolismo , Factor de Transcripción Activador 3/química , Sitios de Unión/efectos de los fármacos , Camptotecina/farmacología , Línea Celular Tumoral , Perfilación de la Expresión Génica , Regulación de la Expresión Génica/efectos de los fármacos , Técnicas de Inactivación de Genes , Células HCT116 , Células HEK293 , Humanos , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
Abstract Regulatory single nucleotide polymorphisms (rSNPs) which change the transcriptional factor binding sites (TFBS) for transcriptional factors (TFs) to bind DNA were reviewed for the ADRBK1 (GRK2), AKT3, ATF3, DIO2, TBXA2R and VEGFA genes. Changes in the TFBS where TFs attach to regulate these genes may result in human sickness and disease. The highlights of this previous work were reviewed for these genes.
Asunto(s)
Polimorfismo de Nucleótido Simple , Factores de Transcripción/metabolismo , Factor de Transcripción Activador 3/química , Factor de Transcripción Activador 3/genética , Factor de Transcripción Activador 3/metabolismo , Sitios de Unión , Quinasa 2 del Receptor Acoplado a Proteína-G/química , Quinasa 2 del Receptor Acoplado a Proteína-G/genética , Quinasa 2 del Receptor Acoplado a Proteína-G/metabolismo , Estudio de Asociación del Genoma Completo , Humanos , Yoduro Peroxidasa/química , Yoduro Peroxidasa/genética , Yoduro Peroxidasa/metabolismo , Proteínas Proto-Oncogénicas c-akt/química , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Receptores de Tromboxano A2 y Prostaglandina H2/genética , Factores de Transcripción/química , Factores de Transcripción/genética , Regiones no Traducidas , Factor A de Crecimiento Endotelial Vascular/química , Factor A de Crecimiento Endotelial Vascular/genética , Factor A de Crecimiento Endotelial Vascular/metabolismo , Yodotironina Deyodinasa Tipo IIRESUMEN
SUMOylation plays an important role in regulating a wide range of cellular processes. Previously, we showed that ATF3, a stress response mediator, can be SUMOylated and lysine 42 is the major SUMO site. However, the significance of ATF3 SUMOylation in biological processes is still poorly understood. In the present study, we investigated the role of ATF3 SUMOylation on CCND activity and cellular proliferation in human prostate cancer cells. First, we showed that ATF3 can be SUMOylated endogenously in the overexpression system, and lysine 42 is the major SUMO site. Unlike normal prostate tissue and androgen-responsive LNCaP cancer cells, androgen-independent PC3 and DU145 cancer cells did not express ATF3 endogenously. Overexpression of ATF3 increased CCND1/2 expression in PC3 and DU145 cancer cells. Interestingly, we observed that SUMOylation is essential for ATF3-mediated CCND1/2 activation. Finally, we observed that SUMOylation plays a functional role in ATF3-mediated cellular proliferation in PC3 and DU145 cells. Taken together, our results demonstrate that SUMO modification of ATF3 influences CCND1/2 activity and cellular proliferation of prostate cancer PC3 and DU145 cells and explains at least in part how ATF3 functions to regulate cancer development.
Asunto(s)
Factor de Transcripción Activador 3/metabolismo , Ciclina D1/metabolismo , Ciclina D2/metabolismo , Neoplasias de la Próstata/metabolismo , Factor de Transcripción Activador 3/química , Factor de Transcripción Activador 3/genética , Sustitución de Aminoácidos , Andrógenos/metabolismo , Línea Celular Tumoral , Proliferación Celular , Ciclina D1/genética , Ciclina D2/genética , Humanos , Lisina/química , Masculino , Mutagénesis Sitio-Dirigida , Neoplasias Hormono-Dependientes/genética , Neoplasias Hormono-Dependientes/metabolismo , Neoplasias Hormono-Dependientes/patología , Próstata/metabolismo , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/patología , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN Neoplásico/genética , ARN Neoplásico/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Sumoilación , TransfecciónRESUMEN
The utility of antibody reagents for the detection of specific cellular targets for both research and diagnostic applications is widespread and continually expanding. Often it is useful to develop specific antibodies as reagent pairs that distinguish different epitopes of the target such that sandwich enzyme-linked immunosorbent assay can be used for selective and specific detection. However, the identification of pairing antibodies is often cumbersome and labor-intensive even with the use of designed peptide-specific epitopes as antigens. We have developed a robust and high-throughput method for identifying pairing complementary antibodies derived either from commercial sources or during a rabbit hybridoma monoclonal screening and selection process using protein A capture with the AlphaScreen bead-based assay format. We demonstrate the value and effectiveness of this assay with three protein targets: Akt2, ATF3, and NAEß (the ß-subunit of the neddylation activation enzyme).
Asunto(s)
Anticuerpos/química , Inmunoensayo/métodos , Proteína Estafilocócica A/química , Factor de Transcripción Activador 3/química , Factor de Transcripción Activador 3/inmunología , Animales , Anticuerpos/inmunología , Anticuerpos Monoclonales/química , Anticuerpos Monoclonales/inmunología , Anticuerpos Monoclonales/metabolismo , Epítopos/inmunología , Hibridomas/metabolismo , Péptidos/inmunología , Proteínas Proto-Oncogénicas c-akt/química , Proteínas Proto-Oncogénicas c-akt/inmunología , ConejosRESUMEN
Activating transcription factor 3 (ATF3) gene encodes a member of the ATF family of transcription factors and is induced by various stress signals. All members of this family share the basic region-leucine zipper (bZip) DNA binding motif and bind to the consensus sequence TGACGTCA in vitro. Previous reviews and an Internet source have covered the following topics: the nomenclature of ATF proteins, the history of their discovery, the potential interplays between ATFs and other bZip proteins, ATF3-interacting proteins, ATF3 target genes, and the emerging roles of ATF3 in cancer and immunity (see footnote 1). In this review, we present evidence and clues that prompted us to put forth the idea that ATF3 functions as a "hub" of the cellular adaptive-response network. We will then focus on the roles of ATF3 in modulating inflammatory response. Inflammation is increasingly recognized to play an important role for the development of many diseases. Putting this in the context of the hub idea, we propose that modulation of inflammation by ATF3 is a unifying theme for the potential involvement of ATF3 in various diseases.
Asunto(s)
Factor de Transcripción Activador 3/metabolismo , Adaptación Fisiológica , Inflamación/etiología , Inflamación/metabolismo , Transducción de Señal , Factor de Transcripción Activador 3/química , Factor de Transcripción Activador 3/genética , Secuencia de Aminoácidos , Animales , Humanos , Inflamación/genética , Datos de Secuencia Molecular , Procesamiento Proteico-PostraduccionalRESUMEN
To understand pathways mediating the inflammatory responses of human aortic endothelial cells to oxidized phospholipids, we previously used a combination of genetics and genomics to model a coexpression network encompassing >1000 genes. CHAC1 (cation transport regulator-like protein 1), a novel gene regulated by ox-PAPC (oxidized 1-palmitoyl-2-arachidonyl-sn-3-glycero-phosphorylcholine), was identified in a co-regulated group of genes enriched for components of the ATF4 (activating transcription factor 4) arm of the unfolded protein response pathway. Herein, we characterize the role of CHAC1 and validate the network model. We first define the activation of CHAC1 mRNA by chemical unfolded protein response-inducers, but not other cell stressors. We then define activation of CHAC1 by the ATF4-ATF3-CHOP (C/EBP homologous protein), and not parallel XBP1 (X box-binding protein 1) or ATF6 pathways, using siRNA and/or overexpression plasmids. To examine the subset of genes downstream of CHAC1, we used expression microarray analysis to identify a list of 227 differentially regulated genes. We validated the activation of TNFRSF6B (tumor necrosis factor receptor superfamily, member 6b), a FASL decoy receptor, in cells treated with CHAC1 small interfering RNA. Finally, we showed that CHAC1 overexpression enhanced apoptosis, while CHAC1 small interfering RNA suppressed apoptosis, as determined by TUNEL, PARP (poly(ADP-ribose) polymerase) cleavage, and AIF (apoptosis-inducing factor) nuclear translocation.
Asunto(s)
Factor de Transcripción Activador 3/química , Factor de Transcripción Activador 4/química , Proteínas Reguladoras de la Apoptosis/química , Pliegue de Proteína , Transducción de Señal/efectos de los fármacos , Transducción de Señal/inmunología , Factor de Transcripción CHOP/química , Proteínas de Transporte Vesicular/química , Factor de Transcripción Activador 3/genética , Factor Inductor de la Apoptosis/fisiología , Proteínas Reguladoras de la Apoptosis/fisiología , Ditiotreitol/farmacología , Perfilación de la Expresión Génica , Células HeLa , Humanos , Análisis de Secuencia por Matrices de Oligonucleótidos , Fosfatidilcolinas/farmacología , Poli(ADP-Ribosa) Polimerasas/fisiología , Factor de Transcripción CHOP/genética , Tunicamicina/farmacología , Proteínas de Transporte Vesicular/biosíntesis , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/fisiologíaRESUMEN
INTRODUCTION: Hypospadias is a common inborn error of the genital development, whose complex etiology remains elusive. Defects of the androgen metabolism and activity have been found in a subset of boys with hypospadias. Moreover, the balance between androgens and estrogens seems to be important to the proper male genital development. Activating transcription factor 3 (ATF3), an estrogen responsive gene, has been reported to be expressed during sexual development and up-regulated in hypospadic genital skin. We investigated ATF3 as a candidate gene for hypospadias. MATERIAL AND METHODS: Genotyping of eight-tagged single nucleotide polymorphisms (SNP)s was performed in 330 boys with hypospadias and in 380 healthy controls. Screening for mutations in ATF3 was conducted in a subset of boys with hypospadias. ATF3 expression was evaluated in the foreskin of boys with hypospadias and in healthy controls and in the human fetal genitalia by immunohistochemistry. RESULTS: Three common SNPs, spanning a region of about 16 kb in intron 1 of ATF3, are associated with hypospadias. These SNPs are not linked and their effects are independent. The combination of the three risk SNPs yields the highest significance. Mutation screening identified the gene variant c536A>G in one patient and c817C>T in the 3'-UTR in two other patients. ATF3 expression was evidenced in the developing male urethra. CONCLUSIONS: ATF3 gene variants influence the risk of hypospadias. Its hormonal responsiveness may underlie this risk effect. But also other ATF3-dependent biological aspects, such as cell survival and death, response to stress stimuli, or the control of epithelial-mesenchymal interactions, may be of importance.
Asunto(s)
Factor de Transcripción Activador 3/genética , Genitales Masculinos/anomalías , Genitales Masculinos/fisiología , Hipospadias/etiología , Hipospadias/genética , Factor de Transcripción Activador 3/química , Factor de Transcripción Activador 3/metabolismo , Secuencia de Bases , Niño , Análisis Mutacional de ADN , Femenino , Feto , Predisposición Genética a la Enfermedad/epidemiología , Genitales Femeninos/fisiología , Haplotipos , Humanos , Hipospadias/epidemiología , Inmunohistoquímica , Intrones , Modelos Logísticos , Masculino , Datos de Secuencia Molecular , Polimorfismo de Nucleótido Simple , Estructura Cuaternaria de Proteína , Factores de RiesgoRESUMEN
ATF3 is a stress-inducible gene that encodes a member of the ATF/CREB family of transcription factors. Current literature indicates that ATF3 affects cell death and cell cycle progression. However, controversies exist, because it has been demonstrated to be a negative or positive regulator of these processes. We sought to study the roles of ATF3 in both cell death and cell cycle regulation in the same cell type using mouse fibroblasts. We show that ATF3 promotes apoptosis and cell cycle arrest. Fibroblasts deficient in ATF3 (ATF3(-/-)) were partially protected from UV-induced apoptosis, and fibroblasts ectopically expressing ATF3(-/-) under the tet-off system exhibited features characteristic of apoptosis upon ATF3 induction. Furthermore, ATF3(-/-) fibroblasts transitioned from G(2) to S phase more efficiently than the ATF3(+/+) fibroblasts, suggesting a growth arrest role of ATF3. Consistent with the growth arrest and pro-apoptotic roles of ATF3, ATF3(-) fibroblasts upon Ras transformation exhibited higher growth rate, produced more colonies in soft agar, and formed larger tumor upon xenograft injection than the ATF3(+/+) counterparts. ATF3(-/-) cells, either with or without Ras transformation, had increased Rb phosphorylation and higher levels of various cyclins. Significantly, ATF3 bound to the cyclin D1 promoter as shown by chromatin immunoprecipitation (ChIP) assay and repressed its transcription by a transcription assay. Taken together, our results indicate that ATF3 promotes cell death and cell arrest, and suppresses Ras-mediated tumorigenesis. Potential explanations for the controversy about the roles of ATF3 in cell cycle and cell death are discussed.
Asunto(s)
Factor de Transcripción Activador 3/fisiología , Neoplasias/metabolismo , Proteínas ras/metabolismo , Factor de Transcripción Activador 3/química , Animales , Apoptosis , Bromodesoxiuridina/farmacología , Ciclo Celular , Muerte Celular , Proliferación Celular , Supervivencia Celular , Transformación Celular Neoplásica , Inmunoprecipitación de Cromatina , Ciclina D1/metabolismo , Relación Dosis-Respuesta a Droga , Fibroblastos/metabolismo , Fase G1 , Regulación Neoplásica de la Expresión Génica , Humanos , Immunoblotting , Inmunohistoquímica , MAP Quinasa Quinasa 4/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Trasplante de Neoplasias , Fosforilación , Plásmidos/metabolismo , Proteína de Retinoblastoma/metabolismo , Retroviridae/genética , Fase S , Factores de Tiempo , Transcripción Genética , Rayos UltravioletaRESUMEN
Activating transcription factor 3 (ATF3), a member of the activating transcription factor/cAMP responsive element binding protein (ATF/CREB) family of transcription factors, is induced by many physiological stresses. To investigate the activity of ATF/CREB in cells with physiological stresses, we developed a practical reporter vector, the plasmid pATF/CRE-luc, bearing activating transcription factor/cAMP responsive element (ATF/CRE) binding sites. This plasmid was constructed by inserting three repeats of the ATF/CRE binding element into the plasmid pG5luc, replacing the GAL-4 binding sites. The plasmids pACT/ATF3 and pATF/CRE-luc were transfected into HeLa and NIH3T3 cells, respectively, and the results showed that the expression of luciferase was increased in a dose-dependent manner on plasmid pACT/ATF3. The data suggested that the plasmid pATF/CRE-luc could be used as a sensitive and convenient reporter system of ATF3 activity.