RESUMEN
Muscle differentiation is a complex process in which muscle progenitor cells undergo determination and eventually cellular fusion. This process is heavily regulated by such master transcription factors as MYOD and members of the MEF2 family. Here, we show that the transcription factor ZNF148 plays a direct role in human muscle cell differentiation. Downregulation of ZNF148 drives the formation of a muscle phenotype with rapid expression of myosin heavy chain, even in proliferative conditions. This phenotype was most likely mediated by the robust and swift upregulation of MYOD and MEF2C.
Asunto(s)
Diferenciación Celular , Proteínas de Unión al ADN/metabolismo , Regulación de la Expresión Génica , Músculo Esquelético , Mioblastos/citología , Mioblastos/metabolismo , Factores de Transcripción/metabolismo , Diferenciación Celular/genética , Línea Celular , Línea Celular Transformada , Proteínas de Unión al ADN/genética , Perfilación de la Expresión Génica , Técnicas de Silenciamiento del Gen , Humanos , Desarrollo de Músculos/genética , Músculo Esquelético/metabolismo , Proteína MioD/genética , Proteína MioD/metabolismo , Fenotipo , ARN Interferente Pequeño/genética , Factores de Transcripción/genéticaRESUMEN
Nuclear receptor subfamily 4 group A member 2 (NR4A2) is an orphan nuclear receptor that is over-expressed in cancer and promotes cell proliferation, migration, transformation, and chemoresistance. Increased expression and function of NR4A2 have been attributed to various signaling pathways, but little is known about microRNA (miRNA) regulation of NR4A2 in cancer. To investigate the posttranscriptional regulation of NR4A2, we used a 3' untranslated region (UTR) reporter screen and identified miR-34 as a putative regulator of NR4A2. By using computer predictions, we identified and confirmed an miRNA recognition element in the 3' UTR of NR4A2 that was responsible for miR-34-mediated suppression. We next demonstrated that overexpression of exogenous miR-34 or activation of the p53 pathway, which regulates endogenous miR-34 expression, decreased NR4A2 expression. Consistent with previous reports, overexpression of NR4A2 blocked the induction of p53 target genes, including mir-34a. This was a phenotypic effect, as NR4A2 overexpression could rescue cells from p53-induced inhibition of proliferation. In summary, our results are the first characterization of a cancer-related miRNA capable of regulating NR4A2 and suggest a network and possible feedback mechanism involving p53, miR-34, and NR4A2.