RESUMO
In wild-type Caenorhabditis elegans, six cells develop as receptors for gentle touch. In egl-44 and egl-46 mutants, two other neurons, the FLP cells, express touch receptor-like features. egl-44 and egl-46 also affect the differentiation of other neurons including the HSN neurons, two cells needed for egg laying. egl-44 encodes a member of the transcription enhancer factor family. The product of the egl-46 gene, two Drosophila proteins, and two proteins in human and mice define a new family of zinc finger proteins. Both egl-44 and egl-46 are expressed in FLP and HSN neurons (and other cells); expression of egl-46 is dependent on egl-44 in the FLP cells but not in the HSN cells. Wild-type touch cells express egl-46 but not egl-44. Moreover, ectopic expression of egl-44 in the touch cells prevents touch cell differentiation in an egl-46-dependent manner. The sequences of these genes and their nuclear location as seen with GFP fusions indicate that they repress transcription of touch cell characteristics in the FLP cells.
Assuntos
Caenorhabditis elegans/embriologia , Caenorhabditis elegans/genética , Proteínas de Drosophila , Proteínas de Insetos/genética , Mutação , Tato/genética , Alelos , Sequência de Aminoácidos , Animais , Linhagem da Célula , Clonagem Molecular , DNA Complementar/metabolismo , Drosophila , Elementos Facilitadores Genéticos , Biblioteca Gênica , Genes Reporter , Proteínas de Fluorescência Verde , Humanos , Proteínas Luminescentes/metabolismo , Camundongos , Dados de Sequência Molecular , Neurônios/metabolismo , Fenótipo , RNA Mensageiro/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Homologia de Sequência de Aminoácidos , Fatores de Transcrição/metabolismo , Transcrição GênicaRESUMO
Several bioluminescent coelenterates use a secondary fluorescent protein, the green fluorescent protein (GFP), in an energy transfer reaction to produce green light. The most studied of these proteins have been the GFPs from the jellyfish Aequorea victoria and the sea pansy Renilla reniformis. Although the proteins from these organisms are not identical, they are thought to have the same chromophore, which is derived from the primary amino acid sequence of GFP. The differences are thought to be due to changes in the protein environment of the chromophore. Recent interest in these molecules has arisen from the cloning of the Aequorea gfp cDNA and the demonstration that its expression in the absence of other Aequorea proteins results in a fluorescent product. This demonstration indicated that GFP could be used as a marker of gene expression and protein localization in living and fixed tissues. Bacterial, plant and animal (including mammalian) cells all express GFP. The heterologous expression of the gfp cDNA has also meant that it could be mutated to produce proteins with different fluorescent properties. Variants with more intense fluorescence or alterations in the excitation and emission spectra have been produced.