RESUMEN
The homeodomain transcription factor Nanog has been implicated in inhibiting differentiation and controlling pluripotency of embryonic stem (ES) cells. We used ectopic expression of Nanog in the myogenic committed C2 cells to dissect these properties. Expression of Nanog in C2 cells does not alter terminal muscle differentiation but has a profound effect on their switch to differentiate along the osteogenic lineage upon BMP treatment. Gene expression profiling revealed that ERK 1/2 phosphorylation, alkaline-phosphatase activity and osteocalcin expression were induced to much lower extent and remained suppressed even after 96h. in Nanog expressing C2 cells, compared to control C2 cells. Hence, Nanog does not inhibit terminal differentiation of committed cells but it is an inhibitor of trans-differentiation that is dependent on de-novo activation of gene transcription.
Asunto(s)
Proteínas de Unión al ADN/metabolismo , Proteínas de Homeodominio/metabolismo , Mioblastos/citología , Mioblastos/metabolismo , Osteoblastos/citología , Osteoblastos/metabolismo , Osteogénesis/fisiología , Diferenciación Celular , Línea Celular , Células Madre Embrionarias/citología , Células Madre Embrionarias/metabolismo , Regulación del Desarrollo de la Expresión Génica/fisiología , Humanos , Proteína Homeótica NanogRESUMEN
The transcription factor Nanog is uniquely expressed in embryonic stem (ES) cells and in germ cell tumors and is important for self-renewal. To understand the relation between this and cell transformation, we expressed Nanog in NIH3T3 cells, and these cells showed an increased growth rate and a transformed phenotype as demonstrated by foci formation and colony growth in soft agar. This suggests that Nanog possesses an oncogenic potential that may be related to the role it plays in germ cell tumors and to its function in self renewal of ES cells. We studied the transcription targets of Nanog using microarrays to identify Nanog regulated genes. The list of genes regulated by Nanog was unique for each cell type and more than 10% of the Nanog regulated genes, including transcription factors, are primary Nanog targets since their promoters bind Nanog in ES cells. Some of these target genes can explain the transformation of NIH3T3.
Asunto(s)
Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Proteínas de Unión al ADN/metabolismo , Regulación de la Expresión Génica , Proteínas de Homeodominio/metabolismo , Animales , Diferenciación Celular/genética , Núcleo Celular/química , Proteínas de Unión al ADN/análisis , Proteínas de Unión al ADN/genética , Genes/genética , Proteínas de Homeodominio/análisis , Proteínas de Homeodominio/genética , Humanos , Ratones , Células 3T3 NIH , Proteína Homeótica Nanog , Análisis de Secuencia por Matrices de Oligonucleótidos , Regiones Promotoras Genéticas , Factores de Transcripción/genéticaRESUMEN
For centuries, rose has been the most important crop in the floriculture industry; its economic importance also lies in the use of its petals as a source of natural fragrances. Here, we used genomics approaches to identify novel scent-related genes, using rose flowers from tetraploid scented and nonscented cultivars. An annotated petal EST database of approximately 2100 unique genes from both cultivars was created, and DNA chips were prepared and used for expression analyses of selected clones. Detailed chemical analysis of volatile composition in the two cultivars, together with the identification of secondary metabolism-related genes whose expression coincides with scent production, led to the discovery of several novel flower scent-related candidate genes. The function of some of these genes, including a germacrene D synthase, was biochemically determined using an Escherichia coli expression system. This work demonstrates the advantages of using the high-throughput approaches of genomics to detail traits of interest expressed in a cultivar-specific manner in nonmodel plants. EST sequences were submitted to the GenBank database (accession numbers BQ 103855 to BQ 106728).
