RESUMEN
Ectomesenchymoma is a rare mesenchymal malignancy occurring mainly in the pediatric population. The hallmark diagnostic features are a combination of sarcoma, usually rhabdomyosarcoma (RMS) with admixed ganglion cells. The lesion arises either in soft tissues or the cranial cavity, and outcomes vary considerably. Current knowledge about the genetics and biology of ectomesenchymoma is extremely limited with only 4 published karyotypes, showing overlaps only in trisomies 2, 8, and 11. Here, we describe a case with genetic findings that, in conjunction with preexisting observations, offer some additional insights into the genetic aberrations of ectomesenchymoma.
Asunto(s)
Cromosomas Humanos Par 12 , Cromosomas Humanos Par 1 , Reordenamiento Génico , Mesenquimoma/patología , Neoplasias Primarias Secundarias/patología , Proteínas Proto-Oncogénicas c-ets/genética , Proteínas Represoras/genética , Rabdomiosarcoma Embrionario/patología , Neoplasias de los Tejidos Blandos/patología , Resultado Fatal , Femenino , Humanos , Lactante , Mesenquimoma/genética , Neoplasias Primarias Secundarias/genética , Rabdomiosarcoma Embrionario/genética , Neoplasias de los Tejidos Blandos/genética , Translocación Genética , Proteína ETS de Variante de Translocación 6RESUMEN
A zebrafish ortholog of human lengsin was identified by EST analysis of an adult lens cDNA library. During zebrafish development, lengsin transcription is first detected at 24 h post-fertilization (hpf). Immunolocalization, using polyclonal antiserum generated against a Lengsin bacterial fusion protein, detects lens-specific protein in whole-mount embryos at 30 hpf. Lengsin expression in zebrafish follows the temporal expression of the alphaA- alphaB1- and betaB1-crystallin proteins in the lens. At 72 hpf, Lengsin is localized to a subpopulation of differentiating secondary fiber cells, while no expression is detected in the lens epithelial cells or central lens fibers. In the adult lens, Lengsin is restricted to a narrow band of cortical fibers and co-localizes with actin at the lateral faces of these interdigitating cells. Stable transgenic lines, using a 3 kb lengsin genomic fragment to regulate EGFP expression, recapitulate the Lengsin temporal and spatial expression patterns. Lengsin function in zebrafish lens formation was examined by antisense morpholino-mediated translation and mRNA splice inhibition. At 72 hpf, the lengsin morphant lenses are reduced in size and exhibit separations within the cortex due to defects in secondary fiber morphogenesis. The location of the morphant lens defects correlates with the Lengsin protein localization at this age. These results demonstrate Lengsin is required for proper fiber cell differentiation by playing roles in either cell elongation or the establishment of cell interactions.
Asunto(s)
Regulación del Desarrollo de la Expresión Génica , Glutamato-Amoníaco Ligasa/fisiología , Cristalino/crecimiento & desarrollo , Cristalino/metabolismo , Pez Cebra/metabolismo , Animales , Diferenciación Celular , Embrión de Pollo , Cristalinas/metabolismo , ADN Complementario/genética , Colorantes Fluorescentes , Glutamato-Amoníaco Ligasa/genética , Glutamato-Amoníaco Ligasa/metabolismo , Proteínas Fluorescentes Verdes/metabolismo , Humanos , Cristalino/embriología , Cristalino/ultraestructura , Ratones , Microscopía Electrónica , Oligonucleótidos Antisentido , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Especificidad de la Especie , Transgenes , Pez Cebra/embriología , Pez Cebra/crecimiento & desarrolloRESUMEN
Foxe3 is a winged helix/forkhead domain transcription factor necessary for mammalian and amphibian lens development. Human FOXE3 mutations cause anterior segment dysgenesis and cataracts. The zebrafish foxe3 cDNA was PCR amplified from 24 h post-fertilization (hpf) embryo cDNA. The zebrafish foxe3 gene consists of a single exon on chromosome 8 and encodes a 422 amino acid protein. This protein possesses 44% and 67% amino acid identity with the human FOXE3 and Xenopus FoxE4 proteins, respectively. A polyclonal antiserum was generated against a bacterial fusion protein containing the Foxe3 carboxyl terminus. The purified antiserum detects zebrafish Foxe3 on immunoblots, in embryo wholemounts, and frozen tissue sections. The zebrafish Foxe3 protein is first detected in the lens at 31hpf and is restricted to the nucleated cell population, including the epithelial and elongating fiber cells. Knockdown of Foxe3 protein using an antisense morpholino results in small lenses with multilayered epithelial cells and fiber cell dysmorphogenesis. The morphants posses normal retinas, although retinal cell proteins, including rhodopsin, are abnormally expressed in the morphant lens tissue. Functional interactions between foxe3 and pitx3 during lens development were assessed by RT-PCR and comparison of Foxe3 and Pitx3 protein expression in both foxe3 and pitx3 morphants. Immunoblots and immunohistochemistry reveal Pitx3 is expressed in the foxe3 morphant lens, while Pitx3 knockdown results in the elimination of Foxe3 expression. These data demonstrate that Foxe3 is necessary for lens development in zebrafish and that foxe3 lies genetically downstream of pitx3 in a zebrafish lens development pathway.