RESUMO
RNA-binding proteins (RBPs) are essential regulators controlling both the cellular transcriptome and translatome. These processes enable cellular plasticity, an important prerequisite for growth. Cellular growth is a complex, tightly controlled process. Using cancer cells as model, we looked for RBPs displaying strong expression in published transcriptome datasets. Interestingly, we found the Pumilio (Pum) protein family to be highly expressed in all these cells. Moreover, we observed that Pum2 is regulated by basic fibroblast growth factor (bFGF). bFGF selectively enhances protein levels of Pum2 and the eukaryotic initiation factor 4E (eIF4E). Exploiting atomic force microscopy and in vitro pulldown assays, we show that Pum2 selects for eIF4E mRNA binding. Loss of Pum2 reduces eIF4E translation. Accordingly, depletion of Pum2 led to decreased soma size and dendritic branching of mature neurons, which was accompanied by a reduction in essential growth factors. In conclusion, we identify Pum2 as an important growth factor for mature neurons. Consequently, it is tempting to speculate that Pum2 may promote cancer growth.
Assuntos
Fator de Iniciação 4E em Eucariotos/metabolismo , Neurônios/metabolismo , Proteínas de Ligação a RNA/metabolismo , Animais , Fator de Iniciação 4E em Eucariotos/genética , Feminino , Fator 2 de Crescimento de Fibroblastos/metabolismo , Expressão Gênica/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microscopia de Força Atômica/métodos , Neurogênese/fisiologia , Ligação Proteica/fisiologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/genética , Transcriptoma/genéticaRESUMO
Today, DNA nanotechnology is one of the methods of choice to achieve spatiotemporal control of matter at the nanoscale. By combining the peculiar spatial addressability of DNA origami structures with the switchable mechanical movement of small DNA motifs, we constructed reconfigurable DNA nanochambers as dynamic compartmentalization systems. The reversible extension and contraction of the inner cavity of the structures was used to control the distance-dependent energy transfer between two preloaded fluorophores. Interestingly, single-molecule FRET studies revealed that the kinetics of the process are strongly affected by the choice of the switchable motifs and/or actuator sequences, thus offering a valid method for fine-tuning the dynamic properties of large DNA nanostructures. We envisage that the proposed DNA nanochambers may function as model structures for artificial biomimetic compartments and transport systems.