Análisis del papel de la proteína hSTAUFEN1 en procesos de la regulación de la traducción, diferenciación neuronal e infección por el virus de la gripe

• Autores: Joan Peredo Hernández
• Directores de la Tesis: Juan Ontín Montón (dir. tes.), Susana de Lucas Arias (dir. tes.)
• Lectura: En la Universidad Autónoma de Madrid ( España ) en 2013
• Idioma: español
• Tribunal Calificador de la Tesis: Juan Antonio García Alvarez (presid.), Marta Nieto López (secret.), Purificación Fortes (voc.), Javier Díaz Nido (voc.), Juana Díez Antón (voc.)
• Materias:
  • Ciencias de la vida
    • Biología molecular
• Enlaces
  • Tesis en acceso abierto en: Biblos-e Archivo
• Resumen

  • Human Staufen1 is a double-stranded RNA-binding protein that forms ribonucleoprotein complexes about 6 to 10 MDa in size and has been involved in the transport and localized translation of mRNAs. Furthermore, it is associated to the rough endoplasmic reticulum and polysomes and interacts with proteins that participate in different pathways of mRNA repression or decay. In the work presented here, we have analysed its implication in the miRNA-mediated repression of translation. hStaufen1 interacts with the AGO family of proteins and their complexes contain not only mRNAs but also a set of 17 miRNAs, which target some of the detected mRNAs. A more efficient association was found for miR-124 both in HEK293T cells and the human neuroblastoma cell line SHSY5Y. The analysis of endogenous hStaufen1 complexes during in vitro differentiation of human neuroblast cells revealed an alteration of the balance between hStaufen1 isoforms and a redistribution of miR-124 to smaller cellular complexes. To analyse the implication of hStaufen1 in neuronal differentiation we have constructed a stable neuroblastoma cell line in which the expression of hStaufen1 protein can be downregulated by adding doxycycline to the media. This biological tool allowed us to demonstrate a role of hStaufen1 in the branching of dendrites during in vitro neuroblastoma cell differentiation. Finally, to analyze the role of hStaufen1 in the infection of influenza virus, we infected human pulmonary epithelial cells in which hStaufen1 was downregulated. The yield of influenza virus infections was reduced more than 10 times in the various hStaufen1-silenced cells as compared to control cells. The expression levels of viral proteins and their nucleo-cytoplasmic transport were not affected upon hStaufen1 silencing but virus particle production, as determined by purification of virions from supernatants, was reduced. Furthermore, at late times in virus infection, hStaufen1 underwent a relocalization into a perinuclear region, close to the MTOC complex and to the endoplasmic reticulum. These results indicate a role for hStaufen1 in late events of the influenza virus infection, possibly in the vRNP transport to the plasma membrane.