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1.
J Exp Med ; 164(3): 677-94, 1986 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-3746199

RESUMEN

We have fused an H-2- thymoma (BM5R.9) with an H-2+ thymoma (BW5147) and have found that many of the resulting hybrids exhibit an H-2- phenotype. In several hybrids that were analyzed in detail, this phenotype is related to the absence of steady-state H-2 mRNA and shows some instability, possibly related to the loss of chromosomes in segregants. We conclude from our studies that BM5R.9 cells display a trans-acting mechanism that can repress the expression of H-2 antigens, and that the gene(s) causing the repression are not located on chromosome 17. This mechanism is not sufficient to explain the H-2- phenotype of BM5R.9, for which an additional, cis-acting process, must be postulated. We discuss these results in the context of the regulation of expression of the major class I transplantation antigens.


Asunto(s)
Regulación de la Expresión Génica , Antígenos H-2/genética , Timoma/inmunología , Animales , Fusión Celular , Línea Celular , Antígenos H-2/análisis , Células Híbridas , Ratones , Fenotipo , Timoma/genética , Transcripción Genética
2.
J Exp Med ; 168(6): 2077-90, 1988 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-3264323

RESUMEN

To investigate the requirement for CD2 expression in activation of T lymphocytes via the CD3-Ti antigen/MHC receptor complex, we produced and characterized a series of CD2- Jurkat variants. These mutants lack detectable surface CD2 as determined by indirect immunofluorescence, immunoprecipitation analysis, and specific radiolabeled antibody binding assay, but nevertheless, expressed normal numbers of CD3-Ti receptors. As expected, the combination of anti-CD2 antibodies, termed anti-T112 and anti-T113, which are mitogenic for resting T lymphocytes, failed to stimulate activation of these variants. In contrast, triggering of their CD3-Ti components resulted in the normal set of T lymphocyte-associated activation events, including phosphoinositide turnover, elevation in intracellular free calcium, early gene-induction events, and IL-2 production. Assuming that the Jurkat cell line is representative of normal cycling human T lymphocytes, we conclude that the presence of the CD2 molecule on the plasma membrane is not in itself a requirement for an operational CD3-Ti-alpha/beta receptor.


Asunto(s)
Antígenos de Diferenciación de Linfocitos T , Activación de Linfocitos , Receptores de Antígenos de Linfocitos T , Linfocitos T/inmunología , Northern Blotting , Calcio/metabolismo , Línea Celular , Humanos , Mutación , Fosfatidilinositoles/metabolismo , Biosíntesis de Proteínas , Linfocitos T/metabolismo
3.
J Exp Med ; 166(2): 341-61, 1987 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-3036997

RESUMEN

We have previously described the isolation of pH-2d-37, a cDNA clone that encodes a so far unknown, poorly polymorphic, class I surface molecule. We report here the isolation of the corresponding gene, its nucleotide sequence, and its localization in the Tla region of the murine MHC. Using a RNase mapping assay, we have confirmed that the second domain coding region of the 37 gene displays very limited polymorphism, and that the gene is transcribed in a broad variety of cell types, in contrast to the genes encoding the known Qa and TL antigens. Possible functions are discussed.


Asunto(s)
Genes MHC Clase II , Antígenos H-2/genética , Ratones Endogámicos BALB C/genética , Animales , Secuencia de Bases , Mapeo Cromosómico , Enzimas de Restricción del ADN , Ratones , Polimorfismo Genético , ARN Mensajero/análisis , Distribución Tisular
4.
Oncogene ; 25(40): 5570-4, 2006 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-16619036

RESUMEN

Environmental chemicals such as dioxin adversely affect immune, neurological and reproductive functions and have been implicated in cancer development. However, the mechanisms responsible for dioxin toxicity are still poorly understood. Here, we show that dioxin and related pollutants trigger a marked morphological change in epithelial cells that remodel their cytoskeleton to increase interaction with extra cellular matrix while loosening cell-cell contacts. Furthermore, dioxin-treated cells show increased motility. These dioxin-mediated effects are mimicked by constitutive expression and activation of the intracellular dioxin receptor (aryl hydrocarbon receptor (AhR)). They correlate with activation of the Jun NH2-terminal kinase (JNK) and are reverted by treatment with a JNK inhibitor. Dioxin-induced effects occur 48 h post-treatment initiation, a time scale, which argues for a genomic effect of the AhR, linked to induction of target genes. This novel Ahr action on cell plasticity points to a role in cancer progression.


Asunto(s)
Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Metilcolantreno/toxicidad , Dibenzodioxinas Policloradas/metabolismo , Receptores de Hidrocarburo de Aril/metabolismo , Actinas/metabolismo , Benzo(a)Antracenos/metabolismo , Cadherinas/metabolismo , Diferenciación Celular , Línea Celular Tumoral , Movimiento Celular , Regulación hacia Abajo , Células Epiteliales/citología , Células Epiteliales/metabolismo , Humanos , Ligandos , Metilcolantreno/metabolismo , Dibenzodioxinas Policloradas/toxicidad , Receptores de Hidrocarburo de Aril/genética , Receptores de Estrógenos/metabolismo , Transducción de Señal , Humo , Nicotiana
5.
Mol Cell Biol ; 12(12): 5336-44, 1992 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-1333041

RESUMEN

The woodchuck intronless proto-oncogene N-myc2 was initially discovered as a frequent target site for hepadnavirus integration in hepatocellular carcinoma. N-myc2 possesses characteristics of a functional retroposon derived from the woodchuck N-myc gene. We have investigated the regulatory signals governing N-myc2 expression and found that a short promoter, including a variant TATA box and potential binding sites for several transcription factors, is localized in the N-myc2 sequences homologous to the 5' untranslated region of the second N-myc exon. The corresponding region in the intron-containing woodchuck N-myc gene also exhibited promoter activity in transient transfection assays. The high evolutionary conservation of these sequences in mammalian N-myc genes suggests that they contain a cryptic N-myc promoter which may be unmasked in the particular context provided by the N-myc2 retroposon. Although N-myc2, like the woodchuck N-myc gene, contributes to an extended CpG island and was found constitutively hypomethylated, it presents a highly restricted expression pattern in adult animals. Whereas the intron-containing N-myc gene is expressed at low levels in different tissues, N-myc2 mRNA was detected only in brain tissue, raising questions about the functional significance of the maintenance of a second N-myc gene in the woodchuck genome.


Asunto(s)
Encéfalo/metabolismo , Elementos Transponibles de ADN , Genes myc , Neoplasias Hepáticas/genética , Regiones Promotoras Genéticas , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Línea Celular , ADN/metabolismo , Fosfatos de Dinucleósidos/metabolismo , Regulación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Humanos , Marmota , Metilación , Ratones , Datos de Secuencia Molecular , Especificidad de Órganos/genética , Proto-Oncogenes Mas , Homología de Secuencia de Ácido Nucleico , Regiones Terminadoras Genéticas , Transcripción Genética , Células Tumorales Cultivadas
6.
Mol Cell Biol ; 10(5): 2407-12, 1990 May.
Artículo en Inglés | MEDLINE | ID: mdl-1691441

RESUMEN

A chimeric receptor composed of the extracellular domain of the human T-cell antigen CD2 (T11) joined to the membrane-spanning segment and the intracellular tyrosine kinase domain of the human colony-stimulating factor 1 receptor (CSF-1R) was expressed in murine NIH 3T3 fibroblasts. Stimulation of these cells with monoclonal antibodies to CD2 induced phosphorylation of the chimeric glycoprotein on tyrosine, receptor downmodulation, and mitogenesis. In contrast, neither human CSF-1R nor the chimeric receptor was able to function in interleukin-2-dependent murine T cells. In fibroblasts, then, CSF-1 per se is not required for activation of the receptor kinase or for a biological response, whereas in T cells, CSF-1R may be unable to engage the downstream signal transduction machinery.


Asunto(s)
Antígenos de Diferenciación de Linfocitos T/fisiología , División Celular , Proteínas Proto-Oncogénicas/fisiología , Receptores de Superficie Celular/fisiología , Receptores Inmunológicos/fisiología , Secuencia de Aminoácidos , Anticuerpos Monoclonales/inmunología , Secuencia de Bases , Antígenos CD2 , Regulación hacia Abajo , Epítopos , Datos de Secuencia Molecular , Fosfotirosina , Proteínas Tirosina Quinasas/fisiología , Receptor de Factor Estimulante de Colonias de Macrófagos , Proteínas Recombinantes de Fusión , Mapeo Restrictivo , Transducción de Señal , Tirosina/análogos & derivados , Tirosina/metabolismo
7.
Oncogene ; 14(9): 1067-74, 1997 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-9070655

RESUMEN

In most cases, Acute Promyelocytic Leukemia (APL) is associated with t(15;17) translocation which juxtaposes sequences from PML and retinoic acid receptor alpha (RAR alpha) genes. The generated PML-RAR alpha fusion interferes with wild type RAR alpha-mediated transcription and disrupts subnuclear compartments, known as PML bodies. Both defects are corrected by all trans retinoic acid (ATRA) therapy which induces differentiation of leukemic cells and clinical remission. In a rare APL syndrome associated with t(11;17), fusion of the RAR alpha gene with the PLZF gene, encoding a Zinc-finger protein produces two reciprocal RAR alpha chimeras. Although PLZF-RAR alpha and PML-RAR alpha are similar in their apparent dominant negative effects, t(11;17)-associated APL is refractory to ATRA therapy. In a yeast two-hybrid genetic screening, we isolated clones encoding the GAL4 transactivation domain fused to various parts of PLZF. Using these autonomously transactivating hybrids, similar in structure to the RAR alpha-PLZF fusion, we mapped the DNA-binding domain of PLZF to the last five Zinc-fingers, a region retained in RAR alpha-PLZF chimera and characterized a specific PLZF target sequence. Our data support the hypothesis that RAR alpha-PLZF chimera is not an inert product of reciprocal translocation and may thus contribute to ATRA unresponsiveness of t(11;17)-associated APL.


Asunto(s)
Proteínas de Unión al ADN/metabolismo , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/metabolismo , Receptores de Ácido Retinoico/metabolismo , Proteínas de Saccharomyces cerevisiae , Factores de Transcripción/metabolismo , Secuencia de Bases , Transformación Celular Neoplásica , Proteínas de Unión al ADN/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Humanos , Factores de Transcripción de Tipo Kruppel , Proteína de la Leucemia Promielocítica con Dedos de Zinc , Receptores de Ácido Retinoico/genética , Proteínas Recombinantes/genética , Receptor alfa de Ácido Retinoico , Factores de Transcripción/genética , Activación Transcripcional , Translocación Genética , Levaduras , Dedos de Zinc/genética
8.
Oncogene ; 19(38): 4417-26, 2000 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-10980617

RESUMEN

Mammalian hepatitis B viruses encode a unique regulatory protein termed X, which is essential for infection and likely plays a role in the carcinogenic process associated with hepadnaviral infection. Among the numerous properties ascribed to X protein, two have been widely documented: promiscuous transcriptional transactivation and proapoptosis. However, full understanding of the mechanisms underlying these activities requires the identification of the genuine X partners among the multiple X-binding host proteins. Here we show that (i) mutations in X protein, which markedly alter affinity for the host protein UVDDBp127, inactivate both transactivation and proapoptosis; (ii) ectopic fusion of a functional UVDDB-binding domain to a deficient binding X mutant restored its activity; (iii) in contrast to the loss-of-binding mutants, a mutant with a strong gain-of-binding exerted trans-dominant negative effects on wt X activity and localized in the nucleus and (iv) increase in intracellular UVDDB concentration enhanced both wt X-mediated transactivation and apoptosis. Taken together, our data provide strong evidence for a common upstream step in X mode of action, consisting of its productive interaction with UVDDB, via a structurally and functionally autonomous module. In addition, they underscore a nuclear location step of the viral protein that depends on its ability to bind UVDDB.


Asunto(s)
Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Transactivadores/metabolismo , Apoptosis/fisiología , Transporte Biológico , Línea Celular , Núcleo Celular/metabolismo , Supervivencia Celular , Virus de la Hepatitis B de la Marmota/química , Humanos , Mutación , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Activación Transcripcional , Proteínas Reguladoras y Accesorias Virales
9.
Oncogene ; 12(9): 2011-7, 1996 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-8649862

RESUMEN

Three hepatitis B viruses infecting humans, woodchucks and ground squirrels increase the risk of hepatocellular carcinoma in their respective hosts. The woodchuck hepatitis B virus (WHV), unlike the two other viruses, induces a rapid carcinogenic process characterized by direct activation of myc proto-oncogenes by insertion of viral DNA. The highly preferred target of insertional mutagenesis in woodchucks is N-myc2, an intronless N-myc gene. Strikingly, N-myc2 has no human homolog and the homologous N-myc2 locus previously detected in the ground squirrel genome, remains silent during hepatocarcinogenesis. Therefore, N-myc2 may represent a critical host determinant in the evolution of the disease associated with hepadnavirus infection. To address this question, we performed a structural and functional analysis of the ground squirrel N-myc2 locus. We show that ground squirrel N-myc2 is highly homologous to its woodchuck counterpart and is a functional proto-oncogene. Existence of a functional N-myc2 gene as a potential target for insertional activation by viral DNA is therefore not restricted to the woodchuck species. This suggests that viral rather than host factors determine the higher oncogenic phenotype of WHV as compared to the two other mammalian hepadnaviruses.


Asunto(s)
Genes myc , Hepadnaviridae/patogenicidad , Neoplasias Hepáticas Experimentales/virología , Retroelementos , Sciuridae/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Secuencia Conservada , ADN Viral , Neoplasias Hepáticas Experimentales/genética , Datos de Secuencia Molecular , Proto-Oncogenes Mas , Ratas , Ratas Endogámicas F344 , Homología de Secuencia de Aminoácido , Transcripción Genética
10.
Oncogene ; 19(38): 4427-31, 2000 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-10980618

RESUMEN

A fully effective treatment of chronic human hepatitis B virus (HBV) infection is still missing and HBV remains the first etiological agent of liver cancer. Although the viral regulatory X protein is essential for infection, its mode of action remains obscure, due the lack of an in vitro infection system. In the accompanying study, we showed the functional importance of interaction between X and the host protein UVDDB-p127, in the transactivation and apoptotic properties of the viral protein. Here, we addressed the biological role of X-UVDDB interaction in the infectious process using a genetic approach in the woodchuck virus closely related to HBV. We show that (i) mutations in X, which markedly affect UVDDB-binding, also abolished productive infection in woodchucks, (ii) in the few cases where mutant viruses led to infection, compensatory mutations had occurred in the X gene of the viral progeny, which restored correct UVDDB-binding. We conclude that efficient viral replication in vivo requires proper X-UVDDB interaction. The interaction may thus provide a novel therapeutic target for the treatment of hepatitis


Asunto(s)
Proteínas de Unión al ADN/metabolismo , Virus de la Hepatitis B de la Marmota/genética , Virus de la Hepatitis B de la Marmota/patogenicidad , Transactivadores/metabolismo , Animales , Hepatitis B/veterinaria , Hepatitis B/virología , Virus de la Hepatitis B de la Marmota/metabolismo , Marmota , Mutación , Transactivadores/genética , Proteínas Reguladoras y Accesorias Virales , Replicación Viral/genética
11.
Oncogene ; 18(18): 2860-71, 1999 May 06.
Artículo en Inglés | MEDLINE | ID: mdl-10362257

RESUMEN

The role of hepatitis B virus HBx protein in the carcinogenesis associated with chronic viral infection remains ill-defined. Indeed, pleiotropic effects have been ascribed to HBx: in addition to its well-documented ability to indirectly stimulate transcription, the protein has been reported to affect cell growth, signal transduction, DNA repair and apoptosis. In this work, we generated Chang (CCL-13)-derived cell lines constitutively expressing wild type or mutant HBx, as a model of HBx-host cell interaction closer to the chronic infection setting, than the classically used transient expression systems. We document the potentiation by HBx of the apoptotic cell death pathway in the recipient cells. This effect is unlikely to rely on p53 activity since the protein is functionally inactivated in CCL-13. In addition, antioxidants and cyclosporin A failed to reduce the apoptotic response back to the normal level, suggesting that production of reactive oxygen species and calcineurin activation are not directly involved in the proapoptotic effect of HBx. In contrast, our data show that transactivation and stimulation of apoptosis are tightly linked HBx activities. Finally, expression of transactivation-active protein did not result in detectable change in the pattern of MAP kinases phosphorylation nor did it affect the ability of the host cell to repair in vitro irradiated plasmid DNA.


Asunto(s)
Apoptosis/fisiología , Antígenos de la Hepatitis B/genética , Antígenos de la Hepatitis B/metabolismo , Proteínas Quinasas/genética , Proteínas Quinasas/metabolismo , Transactivadores/genética , Transactivadores/metabolismo , Activación Transcripcional , Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , División Celular/efectos de los fármacos , Línea Celular/efectos de los fármacos , Línea Celular/virología , Ciclosporina/farmacología , Reparación del ADN/genética , Etopósido/farmacología , Humanos , Mutación , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Transfección , Proteínas Reguladoras y Accesorias Virales
12.
Gene ; 61(2): 145-54, 1987.
Artículo en Inglés | MEDLINE | ID: mdl-3443306

RESUMEN

We have studied the pattern of expression of the Q10 gene, a H-2 class-I gene located in the major histocompatibility complex which encodes a soluble class-I molecule, in the mid-gestation mouse embryo, and compared it to those of two other class-I genes, namely Kd and 37, the latter gene located in the thymus leukemia region. We found that the steady-state amount of these different mRNAs gradually increased from day 13 to day 18. By comparison with the level of expression of these genes in adult liver, the increase during gestation was fairly more marked for Q10 mRNA than for the others. Furthermore, we found that the Q10 gene is transiently expressed in the endoderm layer of the visceral yolk sac and in the fetal heart. Expression in the latter tissue decreases abruptly while increasing in the liver. It has been proposed that the Q10 protein is involved in immune tolerance. However, the time course of expression of Q10 mRNA and its tissue distribution during embryogenesis suggest that the Q10 protein could play a role in the differentiation of hematopoietic stem cells.


Asunto(s)
Genes MHC Clase I , Antígenos H-2/genética , Ratones/genética , Animales , Regulación de la Expresión Génica , Hígado/embriología , Ratones/embriología , ARN Mensajero/genética , Distribución Tisular , Saco Vitelino/fisiología
13.
Gene ; 242(1-2): 369-79, 2000 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-10721731

RESUMEN

The hepatitis C virus (HCV) causes severe liver disease, including liver cancer. A vaccine preventing HCV infection has not yet been developed, and, given the increasing number of infected people, this virus is now considered a major public-health problem. The HCV genome is a plus-stranded RNA that encodes a single polyprotein processed into at least 10 mature polypeptides. So far, only the interaction between the protease NS3 and its cofactor, NS4A, which is involved in the processing of the non-structural region, has been extensively studied. Our work was aimed at constructing a protein interaction map of HCV. A classical two-hybrid system failed to detect any interactions between mature HCV polypeptides, suggesting incorrect folding, expression or targetting of these proteins. We therefore developed a two-hybrid strategy, based on exhaustive screens of a random genomic HCV library. Using this method, we found known interactions, such as the capsid homodimer and the protease dimer, NS3-NS4A, as well as several novel interactions such as NS4A-NS2. Thus, our results are consistent with the idea that the use of a random genomic HCV library allows the selection of correctly folded viral protein fragments. Interacting domains of the viral polyprotein are identified, opening the possibility of developing specific anti-viral agents, based on their ability to modulate these interactions.


Asunto(s)
Genoma Viral , Hepacivirus/genética , Proteínas Virales/metabolismo , Glutatión Transferasa/genética , Hepacivirus/metabolismo , Unión Proteica , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Saccharomyces cerevisiae/genética , Técnicas del Sistema de Dos Híbridos , Proteínas no Estructurales Virales/genética , Proteínas no Estructurales Virales/metabolismo , Proteínas Virales/genética
16.
Oncogene ; 28(41): 3642-51, 2009 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-19648964

RESUMEN

Aryl hydrocarbon receptor (AhR), or dioxin receptor, is a transcription factor that induces adaptive metabolic pathways in response to environmental pollutants. Recently, other pathways were found to be altered by AhR and its ligands. Indeed, developmental defects elicited by AhR ligands suggest that additional cellular functions may be targeted by this receptor, including cell migration and plasticity. Here, we show that dioxin-mediated activation of Ahr induces Nedd9/Hef1/Cas-L, a member of the Cas protein family recently identified as a metastasis marker. The Hef1 gene induction is mediated by two xenobiotic responsive elements present in this gene promoter. Moreover, using RNA interference, we show that Nedd9/Hef1/Cas-L mediates the dioxin-elicited changes related to cell plasticity, including alterations of cellular adhesion and shape, cytoskeleton reorganization, and increased cell migration. Furthermore, we show that both E-cadherin repression and Jun N-terminal kinases activation by dioxin and AhR also depend on the expression of Nedd9/Hef1/Cas-L. Our study unveils, for the first time, a link between pollutants exposure and the induced expression of a metastasis marker and shows that cellular migration and plasticity markers are regulated by AhR and its toxic ligands.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Movimiento Celular/efectos de los fármacos , Contaminantes Ambientales/toxicidad , Fosfoproteínas/metabolismo , Proteínas Adaptadoras Transductoras de Señales/deficiencia , Proteínas Adaptadoras Transductoras de Señales/genética , Animales , Línea Celular Tumoral , Dioxinas/toxicidad , Regulación hacia Abajo , Técnicas de Silenciamiento del Gen , Humanos , Fosfoproteínas/deficiencia , Fosfoproteínas/genética , Interferencia de ARN , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptores de Hidrocarburo de Aril/deficiencia , Receptores de Hidrocarburo de Aril/genética , Receptores de Hidrocarburo de Aril/metabolismo , Activación Transcripcional/efectos de los fármacos
17.
J Virol ; 68(8): 5291-5, 1994 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-8035528

RESUMEN

We cloned the integrated ground squirrel hepatitis B virus (GSHV) sequences from two hepatomas showing a single viral insertion. The GSHV inserts shared structural features with integrated DNAs of other hepadnaviruses. Insertional activation of a cellular gene appears unlikely: the integrated GSHV sequences lacked the known viral enhancers and were not expressed in the tumors, and we found no evidence for the presence of a gene at the integration site. Our results, together with those earlier studies, suggest that GSHV does not behave as an extensive insertional mutagen, in sharp contrast with the closely related woodchuck hepatitis virus. GSHV may thus cause carcinogenesis by more indirect mechanisms, as does the human hepatitis B virus.


Asunto(s)
Carcinoma Hepatocelular/microbiología , ADN Viral/análisis , Neoplasias Hepáticas/microbiología , Orthohepadnavirus/genética , Integración Viral , Animales , Secuencia de Bases , Carcinoma Hepatocelular/genética , Humanos , Neoplasias Hepáticas/genética , Datos de Secuencia Molecular , Orthohepadnavirus/aislamiento & purificación , Secuencias Repetitivas de Ácidos Nucleicos , Mapeo Restrictivo , Sciuridae
18.
Nucleic Acids Res ; 25(8): 1476-84, 1997 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-9092652

RESUMEN

HNF1 is a liver enriched atypical homeoprotein isolated from vertebrates which is involved in the transcriptional activation of liver, kidney, intestine and pancreas specific genes. HNF1 contains an N-terminal dimerisation and a POU-like domain both essential together with the homeodomain for DNA specific recognition. Using the yeast two-hybrid system we searched for proteins interacting with HNF1. We repeatedly obtained cDNA clones encoding DCOH/4-alpha-carbinolamine dehydratase, an enzyme involved in the oxidation of aromatic amino acids that was shown to bind to and stabilise HNF1 dimers. Using the yeast system, we show that the enzymatic activity of DCOH is not essential for HNF1 binding and that the HNF1 dimerisation domain is sufficient for DCOH binding. Furthermore we demonstrate that both proteins co-localise in co-transfected cells.


Asunto(s)
Hidroliasas/metabolismo , Hígado/metabolismo , Proteínas Nucleares , Factores de Transcripción/metabolismo , Animales , Secuencia de Bases , Línea Celular , Clonación Molecular , ADN Complementario/química , ADN Complementario/metabolismo , Proteínas de Unión al ADN/metabolismo , Biblioteca de Genes , Factor Nuclear 1 del Hepatocito , Factor Nuclear 1-alfa del Hepatocito , Factor Nuclear 1-beta del Hepatocito , Humanos , Hidroliasas/biosíntesis , Mucosa Intestinal/metabolismo , Riñón/metabolismo , Datos de Secuencia Molecular , Mutagénesis Insercional , Páncreas/metabolismo , Proteínas Recombinantes de Fusión/metabolismo , Saccharomyces cerevisiae , Transfección , Vertebrados
19.
Proc Natl Acad Sci U S A ; 86(18): 7108-12, 1989 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-2528731

RESUMEN

The T-cell receptor (TCR) is a molecular complex comprised of a clonally restricted, immunoglobulin-like heterodimer (Ti), responsible for specific antigen recognition, and a set of monomorphic polypeptide CD3 subunits, termed gamma, delta, epsilon, zeta, and eta, presumed to be involved in transmembrane signaling events. To investigate the role of the CD3 epsilon subunit in signal transduction, we have transfected a murine hybridoma T-cell line with either wild-type or variant human CD3 epsilon cDNA that encodes a protein lacking 49 of the 55 cytoplasmic amino acid residues. Both wild-type and truncated CD3 epsilon human proteins assemble with endogenous murine CD3/Ti subunits to form functional surface TCRs: Anti-human CD3 epsilon monoclonal antibodies bind exclusively to these chimeric TCRs and trigger interleukin 2 production from the murine cells. Thus, the CD3 epsilon cytoplasmic domain is not required for assembly of the multimeric TCR. Furthermore, it is dispensable for the transduction of a stimulus delivered to the external part of the molecule, suggesting that interaction between the transmembrane and/or external regions of the other TCR chains is a prerequisite for transmembrane signaling.


Asunto(s)
Antígenos de Diferenciación de Linfocitos T/genética , Genes , Receptores de Antígenos de Linfocitos T/genética , Linfocitos T/inmunología , Animales , Southern Blotting , Complejo CD3 , Línea Celular , Deleción Cromosómica , Clonación Molecular , ADN/genética , ADN/aislamiento & purificación , Humanos , Sustancias Macromoleculares , Mutación
20.
EMBO J ; 3(10): 2383-6, 1984 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-6094182

RESUMEN

The H-2Kd gene, which encodes a mouse major transplantation antigen, was transfected into L TK- mouse fibroblasts. Two transcripts of the gene were detected by S1 nuclease mapping analysis. They correspond to two previously characterized cDNA clones isolated from DBA/2 mouse liver RNA, leading to the conclusion that the H-2Kd gene gives rise to two distinct transcripts through an alternate use of splicing sites. The non-canonical RNA potentially encodes a so far undescribed H-2Kd-like molecule. It is present in all tissues tested (liver, spleen, thymus, kidney) albeit in lower amounts (approximately 10-fold less) than the canonical RNA coding for H-2Kd.


Asunto(s)
Antígenos H-2/genética , Empalme del ARN , Transcripción Genética , Animales , ADN/análisis , Endonucleasas/metabolismo , Hígado/análisis , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos DBA , Endonucleasas Específicas del ADN y ARN con un Solo Filamento
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