RESUMO
Our understanding of Ewing's sarcoma development mediated by the EWS/FLI fusion protein has been limited by a lack of knowledge regarding the tumor cell of origin. To circumvent this, we analyzed the function of EWS/FLI in Ewing's sarcoma itself. By combining retroviral-mediated RNA interference with reexpression studies, we show that ongoing EWS/FLI expression is required for the tumorigenic phenotype of Ewing's sarcoma. We used this system to define the full complement of EWS/FLI-regulated genes in Ewing's sarcoma. Functional analysis revealed that NKX2.2 is an EWS/FLI-regulated gene that is necessary for oncogenic transformation in this tumor. Thus, we developed a highly validated transcriptional profile for the EWS/FLI fusion protein and identified a critical target gene in Ewing's sarcoma development.
Assuntos
Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica/genética , Genes Neoplásicos/genética , Proteínas de Homeodomínio/genética , Proteínas de Fusão Oncogênica/genética , Sarcoma de Ewing/genética , Fatores de Transcrição/genética , Animais , Transformação Celular Neoplásica , Proteína Homeobox Nkx-2.2 , Humanos , Camundongos , Camundongos Nus , Análise em Microsséries , Proteínas Nucleares , Proteína Proto-Oncogênica c-fli-1 , Interferência de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteína EWS de Ligação a RNA , Retroviridae/genética , Transcrição Gênica , Proteínas de Peixe-ZebraRESUMO
The molecular etiology of obesity predisposition is largely unknown. Here, we present evidence that genetic variation in TBC1D1 confers risk for severe obesity in females. We identified a coding variant (R125W) in TBC1D1 that segregated with the disease in 4p15-14-linked obesity pedigrees. In cases derived from pedigrees with the strongest linkage evidence, the variant was significantly associated with obesity (P=0.000007) and chromosomes carrying R125W accounted for the majority of the evidence that originally linked 4p15-14 with the disease. In addition, by selecting families that segregated R125W with obesity, we were able to generate highly significant linkage evidence for an obesity predisposition locus at 4q34-35. This result provides additional and confirming evidence that R125W affects obesity susceptibility, delimits the location of an obesity gene at 4q34-35 and identifies a gene/gene interaction that influences the risk for obesity predisposition. Finally, although the function of TBC1D1 is unknown, the protein is structurally similar to a known regulator of insulin-mediated Glut4 translocation.