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1.
Proc Natl Acad Sci U S A ; 115(28): 7356-7361, 2018 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-29941555

RESUMO

Derangement of cellular differentiation because of mutation or inappropriate expression of specific genes is a common feature in tumors. Here, we show that the expression of ZNF281, a zinc finger factor involved in several cellular processes, decreases during terminal differentiation of murine cortical neurons and in retinoic acid-induced differentiation of neuroblastoma (NB) cells. The ectopic expression of ZNF281 inhibits the neuronal differentiation of murine cortical neurons and NB cells, whereas its silencing causes the opposite effect. Furthermore, TAp73 inhibits the expression of ZNF281 through miR34a. Conversely, MYCN promotes the expression of ZNF281 at least in part by inhibiting miR34a. These findings imply a functional network that includes p73, MYCN, and ZNF281 in NB cells, where ZNF281 acts by negatively affecting neuronal differentiation. Array analysis of NB cells silenced for ZNF281 expression identified GDNF and NRP2 as two transcriptional targets inhibited by ZNF281. Binding of ZNF281 to the promoters of these genes suggests a direct mechanism of repression. Bioinformatic analysis of NB datasets indicates that ZNF281 expression is higher in aggressive, undifferentiated stage 4 than in localized stage 1 tumors supporting a central role of ZNF281 in affecting the differentiation of NB. Furthermore, patients with NB with high expression of ZNF281 have a poor clinical outcome compared with low-expressors. These observations suggest that ZNF281 is a controller of neuronal differentiation that should be evaluated as a prognostic marker in NB.


Assuntos
Biomarcadores Tumorais/biossíntese , Diferenciação Celular , Proteínas de Neoplasias/biossíntese , Neuroblastoma/metabolismo , Neurônios/metabolismo , Transativadores/biossíntese , Fatores de Transcrição/biossíntese , Animais , Biomarcadores Tumorais/genética , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos , Proteínas de Neoplasias/genética , Neuroblastoma/diagnóstico , Neuroblastoma/genética , Neuroblastoma/patologia , Neurônios/patologia , Prognóstico , Proteínas Repressoras , Transativadores/genética , Fatores de Transcrição/genética
2.
Genes Dev ; 25(19): 2031-40, 2011 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-21979916

RESUMO

DNA-dependent protein kinase (DNA-PK) is a central regulator of DNA double-strand break (DSB) repair; however, the identity of relevant DNA-PK substrates has remained elusive. NR4A nuclear orphan receptors function as sequence-specific DNA-binding transcription factors that participate in adaptive and stress-related cell responses. We show here that NR4A proteins interact with the DNA-PK catalytic subunit and, upon exposure to DNA damage, translocate to DSB foci by a mechanism requiring the activity of poly(ADP-ribose) polymerase-1 (PARP-1). At DNA repair foci, NR4A is phosphorylated by DNA-PK and promotes DSB repair. Notably, NR4A transcriptional activity is entirely dispensable in this function, and core components of the DNA repair machinery are not transcriptionally regulated by NR4A. Instead, NR4A functions directly at DNA repair sites by a process that requires phosphorylation by DNA-PK. Furthermore, a severe combined immunodeficiency (SCID)-causing mutation in the human gene encoding the DNA-PK catalytic subunit impairs the interaction and phosphorylation of NR4A at DSBs. Thus, NR4As represent an entirely novel component of DNA damage response and are substrates of DNA-PK in the process of DSB repair.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Quebras de DNA de Cadeia Dupla , Reparo do DNA , Proteína Quinase Ativada por DNA/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas Nucleares/metabolismo , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Animais , Linhagem Celular , Células Cultivadas , Técnicas de Inativação de Genes , Humanos , Camundongos , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Fosforilação , Transporte Proteico , Imunodeficiência Combinada Severa/genética , Imunodeficiência Combinada Severa/fisiopatologia
3.
Exp Cell Res ; 329(1): 94-100, 2014 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-25173987

RESUMO

Cellular systems for DNA repair ensure prompt removal of DNA lesions that threaten the genomic stability of the cell. Transcription factors (TFs) have long been known to facilitate DNA repair via transcriptional regulation of specific target genes encoding key DNA repair proteins. However, recent findings identified TFs as DNA repair components acting directly at the DNA lesions in a transcription-independent fashion. Together this recent progress is consistent with the hypothesis that TFs have acquired the ability to localize DNA lesions and function by facilitating chromatin remodeling at sites of damaged DNA. Here we review these recent findings and discuss how TFs may function in DNA repair.


Assuntos
Montagem e Desmontagem da Cromatina , Dano ao DNA/genética , Reparo do DNA/genética , Fatores de Transcrição/metabolismo , Animais , Humanos
4.
J Pharmacol Toxicol Methods ; 108: 106956, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33609731

RESUMO

Göttingen Minipigs show several anatomical, physiological, and pathogenetical similarities to humans and serve an important role in translational studies for example as large animal models of disease. In recent years, the number of transgenic Göttingen Minipigs models has increased, as advanced genetic techniques simplify the generation of animals with precisely tailored modifications. These modifications are designed to replicate genetic alterations responsible for human disease. In addition to serving as valuable large animal disease models, transgenic Göttingen Minipigs are also considered promising donors for xenotransplantation. Current technologies for generation of transgenic minipigs demand a long development and production time of typically 2-3 years. To overcome this limitation and expand the use of Göttingen Minipigs for disease modelling and drug testing, we developed the GENISYST (Genomics Integrated Systems Transgenesis) technology platform for rapid and efficient generation of minipigs based transgenic disease models. As proof of concept, we report the successful generation of transgenic minipigs expressing green fluorescent protein (GFP) in multiple disease-relevant tissues including liver, heart, kidney, lungs, and the central nervous system (CNS). Our data demonstrates the feasibility, efficiency, and utility of GENISYST for rapid one-step generation of transgenic minipigs for human disease modelling in drug discovery and development.


Assuntos
Mutação com Ganho de Função , Genômica , Animais , Modelos Animais de Doenças , Técnicas de Transferência de Genes , Humanos , Suínos/genética , Porco Miniatura
5.
Oncogene ; 39(4): 754-766, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31570788

RESUMO

Efficient repair of DNA double-strand breaks (DSBs) is of critical importance for cell survival. Although non-homologous end joining (NHEJ) is the most used DSBs repair pathway in the cells, how NHEJ factors are sequentially recruited to damaged chromatin remains unclear. Here, we identify a novel role for the zinc-finger protein ZNF281 in participating in the ordered recruitment of the NHEJ repair factor XRCC4 at damage sites. ZNF281 is recruited to DNA lesions within seconds after DNA damage through a mechanism dependent on its DNA binding domain and, at least in part, on poly-ADP ribose polymerase (PARP) activity. ZNF281 binds XRCC4 through its zinc-finger domain and facilitates its recruitment to damaged sites. Consequently, depletion of ZNF281 impairs the efficiency of the NHEJ repair pathway and decreases cell viability upon DNA damage. Survival analyses from datasets of commonly occurring human cancers show that higher levels of ZNF281 correlate with poor prognosis of patients treated with DNA-damaging therapies. Thus, our results define a late ZNF281-dependent regulatory step of NHEJ complex assembly at DNA lesions and suggest additional possibilities for cancer patients' stratification and for the development of personalised therapeutic strategies.


Assuntos
Quebras de DNA de Cadeia Dupla , Reparo do DNA por Junção de Extremidades , Neoplasias/genética , Neoplasias/patologia , Proteínas Repressoras/metabolismo , Sistemas CRISPR-Cas , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/metabolismo , Bases de Dados Genéticas , Humanos , Neoplasias/metabolismo , Poli(ADP-Ribose) Polimerase-1/genética , Poli(ADP-Ribose) Polimerase-1/metabolismo , Prognóstico , Proteínas Repressoras/genética , Taxa de Sobrevida
6.
Trends Cell Biol ; 14(7): 369-76, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15246430

RESUMO

Nuclear receptors comprise a large family of proteins that shares a common structure and mechanism of action. Members of this family, first cloned 20 years ago, are regulated by small lipophilic signaling molecules such as steroid hormones, retinoids and thyroid hormone. More recently, the characterization of proteins that resemble nuclear receptors (referred to as orphan receptors) has resulted in the determination of novel signaling pathways. However, many orphan-receptor ligands remain unidentified, and recent structural studies of the binding domains for orphan-receptor ligands suggest that not all of these receptors use ligand binding in a classical way. Notably, it is now evident that some orphan receptors lack the capacity for ligand binding, which suggests that they are regulated by alternative, ligand-independent mechanisms.


Assuntos
Receptores Citoplasmáticos e Nucleares/química , Receptores Citoplasmáticos e Nucleares/metabolismo , Animais , Sítios de Ligação/fisiologia , Ligantes , Modelos Moleculares , Estrutura Terciária de Proteína
7.
Cell Cycle ; 18(9): 963-975, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30973299

RESUMO

Common hallmarks of cancer include the dysregulation of cell cycle progression and the acquisition of genome instability. In tumors, G1 cell cycle checkpoint induction is often lost. This increases the reliance on a functional G2/M checkpoint to prevent progression through mitosis with damaged DNA, avoiding the introduction of potentially aberrant genetic alterations. Treatment of tumors with ionizing radiation (IR) utilizes this dependence on the G2/M checkpoint. Therefore, identification of factors which regulate this process could yield important biomarkers for refining this widely used cancer therapy. Leucine zipper and ICAT domain containing (LZIC) downregulation has been associated with the development of IR-induced tumors. However, despite LZIC being highly conserved, it has no known molecular function. We demonstrate that LZIC knockout (KO) cell lines show a dysregulated G2/M cell cycle checkpoint following IR treatment. In addition, we show that LZIC deficient cells competently activate the G1 and early G2/M checkpoint but fail to maintain the late G2/M checkpoint after IR exposure. Specifically, this defect was found to occur downstream of PIKK signaling. The LZIC KO cells demonstrated severe aneuploidy indicative of genomic instability. In addition, analysis of data from cancer patient databases uncovered a strong correlation between LZIC expression and poor prognosis in several cancers. Our findings suggest that LZIC is functionally involved in cellular response to IR, and its expression level could serve as a biomarker for patient stratification in clinical cancer practice.


Assuntos
Carcinoma de Células Renais/genética , Pontos de Checagem da Fase G2 do Ciclo Celular/genética , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos da radiação , Peptídeos e Proteínas de Sinalização Intracelular/genética , Neoplasias Renais/genética , Radiação Ionizante , Aneuploidia , Carcinoma de Células Renais/mortalidade , Sobrevivência Celular/genética , Sobrevivência Celular/efeitos da radiação , Quinase 1 do Ponto de Checagem/metabolismo , Dano ao DNA/genética , Dano ao DNA/efeitos da radiação , Bases de Dados Genéticas , Expressão Gênica , Técnicas de Inativação de Genes , Instabilidade Genômica/genética , Células HEK293 , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Neoplasias Renais/mortalidade , Prognóstico , Transdução de Sinais/genética , Transdução de Sinais/efeitos da radiação , Taxa de Sobrevida , Transfecção
8.
Cell Rep ; 26(8): 2028-2036.e6, 2019 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-30784586

RESUMO

Although poly-ADP-ribosylation (PARylation) of DNA repair factors had been well documented, its role in the repair of DNA double-strand breaks (DSBs) is poorly understood. NR4A nuclear orphan receptors were previously linked to DSB repair; however, their function in the process remains elusive. Classically, NR4As function as transcription factors using a specialized tandem zinc-finger DNA-binding domain (DBD) for target gene induction. Here, we show that NR4A DBD is bi-functional and can bind poly-ADP-ribose (PAR) through a pocket localized in the second zinc finger. Separation-of-function mutants demonstrate that NR4A PAR binding, while dispensable for transcriptional activity, facilitates repair of radiation-induced DNA double-strand breaks in G1. Moreover, we define DNA-PKcs protein as a prominent target of ionizing radiation-induced PARylation. Mechanistically, NR4As function by directly targeting poly-ADP-ribosylated DNA-PKcs to facilitate its autophosphorylation-promoting DNA-PK kinase assembly at DNA lesions. Selective targeting of the PAR-binding pocket of NR4A presents an opportunity for cancer therapy.


Assuntos
Reparo do DNA , Proteína Quinase Ativada por DNA/metabolismo , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Sítios de Ligação , Linhagem Celular Tumoral , Proteína Quinase Ativada por DNA/química , Células HEK293 , Humanos , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/química , Poli ADP Ribosilação , Poli Adenosina Difosfato Ribose/química , Poli Adenosina Difosfato Ribose/metabolismo , Ligação Proteica , Dedos de Zinco
9.
Nat Commun ; 9(1): 3877, 2018 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-30250067

RESUMO

PAXX is a recently identified component of the nonhomologous end joining (NHEJ) DNA repair pathway. The molecular mechanisms of PAXX action remain largely unclear. Here we characterise the interactomes of PAXX and its paralogs, XLF and XRCC4, to show that these factors share the ability to interact with DNA polymerase λ (Pol λ), stimulate its activity and are required for recruitment of Pol λ to laser-induced DNA damage sites. Stimulation of Pol λ activity by XRCC4 paralogs requires a direct interaction between the SP/8 kDa domain of Pol λ and their N-terminal head domains to facilitate recognition of the 5' end of substrate gaps. Furthermore, PAXX and XLF collaborate with Pol λ to promote joining of incompatible DNA ends and are redundant in supporting Pol λ function in vivo. Our findings identify Pol λ as a novel downstream effector of PAXX function and show XRCC4 paralogs act in synergy to regulate polymerase activity in NHEJ.


Assuntos
Reparo do DNA por Junção de Extremidades/fisiologia , Enzimas Reparadoras do DNA/metabolismo , Proteínas de Ligação a DNA/metabolismo , DNA Polimerase Dirigida por DNA/metabolismo , Linhagem Celular Tumoral , Cromatografia Líquida de Alta Pressão , Quebras de DNA de Cadeia Dupla/efeitos da radiação , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/isolamento & purificação , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/isolamento & purificação , DNA Polimerase Dirigida por DNA/genética , DNA Polimerase Dirigida por DNA/isolamento & purificação , Células HEK293 , Humanos , Lasers/efeitos adversos , Mutagênese Sítio-Dirigida , Ligação Proteica/fisiologia , Domínios Proteicos/fisiologia , Mapeamento de Interação de Proteínas/métodos , Mapas de Interação de Proteínas/fisiologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Espectrometria de Massas em Tandem/métodos
10.
Nat Commun ; 9(1): 532, 2018 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-29416038

RESUMO

The error-free and efficient repair of DNA double-stranded breaks (DSBs) is extremely important for cell survival. RNA has been implicated in the resolution of DNA damage but the mechanism remains poorly understood. Here, we show that miRNA biogenesis enzymes, Drosha and Dicer, control the recruitment of repair factors from multiple pathways to sites of damage. Depletion of Drosha significantly reduces DNA repair by both homologous recombination (HR) and non-homologous end joining (NHEJ). Drosha is required within minutes of break induction, suggesting a central and early role for RNA processing in DNA repair. Sequencing of DNA:RNA hybrids reveals RNA invasion around DNA break sites in a Drosha-dependent manner. Removal of the RNA component of these structures results in impaired repair. These results show how RNA can be a direct and critical mediator of DNA damage repair in human cells.


Assuntos
Dano ao DNA , Reparo do DNA , DNA/metabolismo , RNA/metabolismo , Ribonuclease III/metabolismo , Células A549 , Linhagem Celular Tumoral , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , DNA/genética , Quebras de DNA de Cadeia Dupla , Reparo do DNA por Junção de Extremidades , Perfilação da Expressão Gênica , Recombinação Homóloga , Humanos , RNA/genética , Interferência de RNA , Ribonuclease III/genética
11.
Cell Death Discov ; 3: 17071, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29152378

RESUMO

Zinc-finger proteins (ZNFs) are one of the most abundant groups of proteins and have a wide range of molecular functions. Given the wide variety of zinc-finger domains, ZNFs are able to interact with DNA, RNA, PAR (poly-ADP-ribose) and other proteins. Thus, ZNFs are involved in the regulation of several cellular processes. In fact, ZNFs are implicated in transcriptional regulation, ubiquitin-mediated protein degradation, signal transduction, actin targeting, DNA repair, cell migration, and numerous other processes. The aim of this review is to provide a comprehensive summary of the current state of knowledge of this class of proteins. Firstly, we describe the actual classification of ZNFs, their structure and functions. Secondly, we focus on the biological role of ZNFs in the development of organisms under normal physiological and pathological conditions.

12.
J Mol Endocrinol ; 37(2): 317-26, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17032747

RESUMO

The recently solved crystal structure of the orphan nuclear receptor (NR) Nurr1 ligand-binding domain (LBD) showed that Nurr1 lacks a cavity for ligand binding and a canonical NR co-activator-binding site. Computer modeling of the Nurr1 LBD structure identified a hydrophobic region on the surface of the Nurr1 LBD that was positioned on the opposite side from the classical co-activator-binding site. Site-directed mutagenesis demonstrated that this region is critical for the activity of the Nurr1 LBD. Most mutations introduced in this region reduced or abolished transcriptional activity of the Nurr1 LBD, but mutation at lysine (K577) resulted in a drastically increased activity. Moreover, the activity of the Nurr1 LBD was shown to correlate with a propensity for proteasome-dependent degradation revealing a close association between activity and Nurr1 protein turnover. These data provide novel insights into the mechanisms of transcription via the Nurr1 LBD and identify an alternative co-activator-binding surface that is unique to the NR4A family of NRs.


Assuntos
Proteínas de Transporte/metabolismo , Proteínas de Ligação a DNA/química , Ligantes , Fatores de Transcrição/química , Sítios de Ligação , Células Cultivadas , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Dimerização , Humanos , Modelos Moleculares , Mutação , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares , Especificidade de Órgãos , Ligação Proteica , Desnaturação Proteica/fisiologia , Estrutura Terciária de Proteína , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores X de Retinoides/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Ativação Transcricional , Transfecção
14.
Development ; 135(10): 1843-51, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18417619

RESUMO

The preservation of a pool of neural precursors is a prerequisite for proper establishment and maintenance of a functional central nervous system (CNS). Both Notch signaling and SoxB1 transcription factors have been ascribed key roles during this process, but whether these factors use common or distinct mechanisms to control progenitor maintenance is unsettled. Here, we report that the capacity of Notch to maintain neural cells in an undifferentiated state requires the activity of SoxB1 proteins, whereas the mechanism by which SoxB1 block neurogenesis is independent of Notch signaling. A common feature of Notch signaling and SoxB1 proteins is their ability to inhibit the activity of proneural bHLH proteins. Notch represses the transcription of proneural bHLH genes, while SoxB1 proteins block their neurogenic capacity. Moreover, E-proteins act as functional partners of proneural proteins and the suppression of E-protein expression is an important mechanism by which Notch counteracts neurogenesis. Interestingly, in contrast to the Hes-dependent repression of proneural genes, suppression of E-protein occurs in a Hes-independent fashion. Together, these data reveal that Notch signaling and SoxB1 transcription factors use distinct regulatory mechanisms to control proneural protein function and to preserve neural cells as undifferentiated precursors.


Assuntos
Sistema Nervoso Central/citologia , Tubo Neural/citologia , Neurônios/fisiologia , Células-Tronco/fisiologia , Fatores de Transcrição/fisiologia , Animais , Diferenciação Celular/fisiologia , Sistema Nervoso Central/embriologia , Sistema Nervoso Central/metabolismo , Embrião de Galinha , Regulação da Expressão Gênica no Desenvolvimento , Morfogênese/fisiologia , Tubo Neural/metabolismo , Neurônios/metabolismo , Receptores Notch/fisiologia , Transdução de Sinais , Células-Tronco/metabolismo
15.
Genes Dev ; 20(24): 3475-86, 2006 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-17182872

RESUMO

The progression of neurogenesis relies on proneural basic helix-loop-helix (bHLH) transcription factors. These factors operate in undifferentiated neural stem cells and induce cell cycle exit and the initiation of a neurogenic program. However, the transient expression of proneural bHLH proteins in neural progenitors indicates that expression of neuronal traits must rely on previously unexplored mechanisms operating downstream from proneural bHLH proteins. Here we show that the HMG-box transcription factors Sox4 and Sox11 are of critical importance, downstream from proneural bHLH proteins, for the establishment of pan-neuronal protein expression. Examination of a neuronal gene promoter reveals that Sox4 and Sox11 exert their functions as transcriptional activators. Interestingly, the capacity of Sox4 and Sox11 to induce the expression of neuronal traits is independent of mechanisms regulating the exit of neural progenitors from the cell cycle. The transcriptional repressor protein REST/NRSF has been demonstrated to block neuronal gene expression in undifferentiated neural cells. We now show that REST/NRSF restricts the expression of Sox4 and Sox11, explaining how REST/NRSF can prevent precocious expression of neuronal proteins. Together, these findings demonstrate a central regulatory role of Sox4 and Sox11 during neuronal maturation and mechanistically separate cell cycle withdrawal from the establishment of neuronal properties.


Assuntos
Proteínas Aviárias/fisiologia , Fatores de Transcrição Hélice-Alça-Hélice Básicos/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Proteínas HMGB/fisiologia , Neurônios/citologia , Ativação Transcricional , Animais , Proteínas Aviárias/genética , Diferenciação Celular , Embrião de Galinha , Proteínas HMGB/genética , Camundongos , Neurônios/metabolismo , Regiões Promotoras Genéticas
16.
J Biol Chem ; 278(35): 32825-33, 2003 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-12813034

RESUMO

Activation-induced cell death (AICD), a term originally coined for the anti-CD3-induced apoptosis of T cell hybridomas and thymocytes, is predominantly driven by death receptors and has been involved in the control of autoreactive T cells in the periphery. In the Do-11.10 T cell hybridoma model of AICD, activation of the T cell receptor (TCR) results in Fas-dependent apoptosis. Here, we show that inhibition of the transcription factor nuclear factor kappa B (NF kappa B) in Do-11.10 cells resulted in increased sensitivity to TCR-mediated apoptosis, correlating with defective induction of the anti-apoptotic NF kappa B target gene A20. Stable expression of the zinc finger protein A20 in NF kappa B-negative Do-11.10 cells rescued the phenotype. TCR activation in NF kappa B-deficient Do-11.10 cells resulted predominantly in tumor necrosis factor (TNF) receptor 2 (TNFR2)-dependent bystander cell death rather than classical Fas-dependent AICD. Strikingly, A20 blocked TNF-mediated apoptosis and simultaneously restored TCR-induced Fas-dependent AICD. In addition, NF kappa B downstream of TNFR was required for up-regulation of Fas expression by endogenous TNF secreted in response to TCR stimulation. Together, these results suggest that NF kappa B can play both pro- and anti-apoptotic roles during AICD. We propose that NF kappa B controls the balance between Fas and TNF cell death pathways during AICD via the expression of the zinc finger protein A20.


Assuntos
NF-kappa B/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Animais , Apoptose , Western Blotting , Complexo CD3/metabolismo , Morte Celular , Dimerização , Proteína Ligante Fas , Citometria de Fluxo , Vetores Genéticos , Hibridomas/metabolismo , Glicoproteínas de Membrana/metabolismo , Camundongos , Modelos Biológicos , Fenótipo , Plasmídeos/metabolismo , RNA Mensageiro/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Retroviridae/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Linfócitos T/metabolismo , Fatores de Tempo , Transfecção , Regulação para Cima , Dedos de Zinco , Receptor fas/metabolismo
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