RESUMEN
Pleiomorphic adenoma of the salivary glands is a benign epithelial tumour occurring primarily in the major and minor salivary glands. It is by far the most common type of salivary gland tumour. Microscopically, pleiomorphic adenomas show a marked histological diversity with epithelial, myoepithelial and mesenchymal components in a variety of patterns. In addition to a cytogenetic subgroup with normal karyotypes, pleiomorphic adenomas are characterized by recurrent chromosome rearrangements, particularly reciprocal translocations, with breakpoints at 8q12, 3p21, and 12q13-15, in that order of frequency. The most common abnormality is a reciprocal t(3;8)(p21;q12). We here demonstrate that the t(3;8)(p21;q12) results in promoter swapping between PLAG1, a novel, developmentally regulated zinc finger gene at 8q12, and the constitutively expressed gene for beta-catenin (CTNNB1), a protein interface functioning in the WG/WNT signalling pathway and specification of cell fate during embryogenesis. Fusions occur in the 5'-non-coding regions of both genes, exchanging regulatory control elements while preserving the coding sequences. Due to the t(3;8)(p21;q12), PLAG1 is activated and expression levels of CTNNB1 are reduced. Activation of PLAG1 was also observed in an adenoma with a variant translocation t(8;15)(q12;q14). Our results indicate that PLAG1 activation due to promoter swapping is a crucial event in salivary gland tumourigenesis.
Asunto(s)
Adenoma Pleomórfico/genética , Cromosomas Humanos Par 3/genética , Cromosomas Humanos Par 8/genética , Proteínas del Citoesqueleto/genética , Proteínas de Unión al ADN/genética , Genes , Proteínas de Fusión Oncogénica/genética , Regiones Promotoras Genéticas , Neoplasias de las Glándulas Salivales/genética , Transactivadores , Translocación Genética/genética , Dedos de Zinc/genética , Adenoma Pleomórfico/patología , Secuencia de Aminoácidos , Secuencia de Bases , Paseo de Cromosoma , Cromosomas Artificiales de Levadura/genética , Cromosomas Humanos Par 3/ultraestructura , Cromosomas Humanos Par 8/ultraestructura , Humanos , Datos de Secuencia Molecular , Neoplasias de las Glándulas Salivales/patología , Alineación de Secuencia , Homología de Secuencia de Aminoácido , beta CateninaAsunto(s)
Personas con Discapacidad , Educación , Legislación como Asunto , Pediatría , Niño , Comunicación , Humanos , Relaciones Interprofesionales , Estados UnidosAsunto(s)
Curriculum , Educación de las Personas con Discapacidad Intelectual , Adolescente , Factores de Edad , Niño , Cognición , Femenino , Humanos , MasculinoAsunto(s)
Educación de las Personas con Discapacidad Intelectual , Educación Especial , Inteligencia , Adolescente , Adulto , Actitud , Niño , Preescolar , Cultura , Humanos , Discapacidad Intelectual/epidemiología , Discapacidad Intelectual/rehabilitación , Política , Educación Compensatoria , Clase Social , Estados UnidosRESUMEN
In our effort to characterize a gene at chromosome 11q13 involved in a t(11;17)(q13;q21) translocation in B-non-Hodgkin lymphoma, we have identified a novel human gene, NOF (Neighbour of FAU). It maps right next to FAU in a head to head configuration separated by a maximum of 146 nucleotides. cDNA clones representing NOF hybridized to a 2. 2-kb mRNA present in all tissues tested. The largest open reading frame appeared to contain 166 amino acids and is proline rich, and the sequence shows no homology with any known gene in the public databases. The NOF gene consists of 4 exons and 3 introns spanning approximately 5 kb, and the boundaries between exons and introns follow the GT/AG rule. The NOF locus is conserved during evolution, with the predicted protein having over 80% identity to three translated mouse and rat ESTs of unknown function. Moreover, the mouse ESTs map in the same organization, closely linked to the FAU gene, in the mouse genome. NOF, however, is not affected by the t(11;17)(q13;q21) chromosomal translocation.
Asunto(s)
Cromosomas Humanos Par 11 , Proteínas/genética , Proteínas Ribosómicas/genética , Transcripción Genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Mapeo Cromosómico , Cromosomas Humanos Par 17 , Clonación Molecular , Secuencia Conservada , ADN Complementario , Exones , Humanos , Intrones , Linfoma de Células B/genética , Ratones , Proteínas Mitocondriales , Datos de Secuencia Molecular , Biosíntesis de Proteínas , ARN Mensajero/biosíntesis , Ratas , Proteínas Ribosómicas/biosíntesis , Homología de Secuencia de Aminoácido , Translocación GenéticaRESUMEN
We have isolated and characterized two novel cDNAs encoding C2H2 zinc finger proteins showing high sequence homology to PLAG1, a protein ectopically activated by promoter swapping or promoter substitution in pleomorphic adenomas with chromosomal abnormalities at chromosome 8q12. PLAG1 and the two new PLAG1 family members (PLAGL1 and PLAGL2) constitute a novel subfamily of zinc finger proteins that recognize DNA and/or RNA. To examine the potential of the three human proteins to modulate transcription, we constructed several PLAG/GAL4 DNA binding domain fusion proteins and measured their ability to activate transcription of a reporter gene construct in different mammalian cell lines and in yeast. Although the carboxyl-terminal part of PLAGL1 shows strong overall transcriptional activity in mesenchymal (COS-1) and epithelial cells (293), both PLAG1 and PLAGL2 transactivate in mesenchymal cells only if depleted from a repressing region. This effect is less profound in epithelial cells. These data suggest that the activation in pleomorphic adenomas of PLAG1 most likely results in uncontrolled activation of downstream target genes.
Asunto(s)
Proteínas de Ciclo Celular , Proteínas de Unión al ADN/genética , Genes Supresores de Tumor , Proteínas de Unión al ARN/genética , Transactivadores/genética , Factores de Transcripción , Dedos de Zinc/genética , Secuencia de Aminoácidos , Animales , Células COS , Clonación Molecular , Secuencia Conservada , Análisis Mutacional de ADN , ADN Complementario/genética , Genes Reporteros , Humanos , Datos de Secuencia Molecular , Familia de Multigenes , Saccharomyces cerevisiae/genética , Análisis de Secuencia de ADN , Eliminación de Secuencia , Homología de Secuencia de Aminoácido , Activación Transcripcional , Proteínas Supresoras de TumorRESUMEN
Pleomorphic adenomas are benign epithelial tumors originating from the major and minor salivary glands. Extensive cytogenetic studies have demonstrated that they frequently show chromosome abnormalities involving chromosome 8, with consistent breakpoints at 8q12. In previous studies, we have shown that these breakpoints are located in a 9-cM interval between MOS/D8S285 and D8S260. Here, we describe directional chromosome walking studies starting from D8S260 as well as D8S285. Using the CEPH and ICRF YAC libraries, these studies resulted in the construction of two nonoverlapping YAC contigs of about 2 and 5 Mb, respectively. Initial fluorescence in situ hybridization (FISH) analysis suggested that the majority of 8q12 breakpoints clustered within the 2-Mb contig, which was mapped to the centromeric part of chromosome band 8q12. This contig has at least double coverage and consists of 34 overlapping YAC clones. The localization of the YACs was confirmed by FISH analysis. On the basis of mapping data of landmarks with an average spacing of 65 kb as well as restriction enzyme analysis, a long-range physical map was established for the chromosome region spanned by the 2-Mb contig. The relative positions of various known genes and expressed sequence tags within this contig were also determined. Subsequent FISH analyses of pleomorphic adenomas using YACs as well as cosmids revealed that all but two of the 8q12 breakpoints in the primary tumors tested mapped within a 300-kb interval between the MOS proto-oncogene and STS EM156. The target gene affected by the chromosome aberrations mapping within this interval was recently shown to be the PLAG1 gene, which encodes a novel zinc finger protein.
Asunto(s)
Adenoma Pleomórfico/genética , Fragilidad Cromosómica , Cromosomas Artificiales de Levadura/genética , Cromosomas Humanos Par 8/genética , Familia de Multigenes/genética , Mapeo Restrictivo , Neoplasias de las Glándulas Salivales/genética , Centrómero/genética , Mapeo Cromosómico , Paseo de Cromosoma/métodos , Islas de CpG/genética , Genes/genética , Genes/fisiología , Marcadores Genéticos/genética , Humanos , Hibridación Fluorescente in Situ , Datos de Secuencia Molecular , Polimorfismo Genético , Proto-Oncogenes Mas , Mapeo Restrictivo/métodos , Glándulas Salivales/química , Glándulas Salivales/patología , Lugares Marcados de SecuenciaRESUMEN
The gene for human Krüppel-related protein 4, (HKR4, gene symbol GLI4), a zinc finger protein of unknown function, has been localized by fluorescence in situ hybridization to chromosome 8q24.3, distal to c-MYC.
Asunto(s)
Cromosomas Humanos Par 4/genética , Proteínas de Unión al ADN/genética , Proteínas Represoras , Factores de Transcripción/genética , Dedos de Zinc/genética , Secuencia de Bases , Mapeo Cromosómico , Cósmidos , Cartilla de ADN/genética , Humanos , Hibridación Fluorescente in Situ , Factores de Transcripción de Tipo Kruppel , Datos de Secuencia MolecularRESUMEN
Cytogenetic aberrations involving 12q13-15 are frequently observed in a variety of benign solid tumors. Using a chromosome walking approach combined with fluorescence in situ hybridization analysis, we were able to show that the chromosome 12 breakpoints involved in uterine leiomyoma, pleomorphic adenoma of the salivary gland, and lipoma cluster to the same chromosomal region, which we therefore designated MAR (multiple-aberration region). By comparing the G-banding pattern of prometaphase chromosomes of amniotic fluid cells and lymphocytes to the position of hybridization signals obtained with a cosmid pool encompassing this breakpoint hot spot region, MAR was assigned to 12q15. We conclude that, despite the cytogenetic breakpoint assignment to the three bands 12q13-15 in individual uterine leiomyomas, lipomas, and pleomorphic adenomas of the salivary glands in the past, most likely 12q15 is the only 12q breakpoint site in these three distinct solid tumor types.
Asunto(s)
Adenoma Pleomórfico/genética , Aberraciones Cromosómicas , Cromosomas Humanos Par 12 , Leiomioma/genética , Lipoma/genética , Neoplasias de las Glándulas Salivales/genética , Neoplasias Uterinas/genética , Paseo de Cromosoma , Femenino , HumanosRESUMEN
The tumour suppressor gene causing multiple endocrine neoplasia type 1 (MEN1) encodes a 610 amino acid protein, menin. In order to identify menin-interacting proteins we used a yeast two-hybrid assay to screen a 12.5-dpc mouse embryo library with partial menin encompassing amino acids 278 to 476. This identified a homeobox containing protein encoded by a placenta and embryonic expression gene, referred to as Pem. GST-pull-down and coimmunoprecipitation experiments confirmed the interaction. Both proteins colocalised predominantly in the nucleus but were occasionally also found in the cytoplasm. Furthermore, in situ hybridisation studies revealed similarities in their expression patterns in mouse embryos and adult tissues. In adult mice both Men1 and Pem yielded strong signals in testis, Sertoli cells and particularly in seminiferous tubules. Thus, our study has identified that menin interacts with Pem, and the high expression of these proteins in the testis suggests a role in spermatogenesis.