Human papillomavirus and human cytomegalovirus: evasion from the cellular antiviral response

• Autor(a) principal: Ramalho, Ana Catarina Campos
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/25694
• topic: Human papillomavirus; Human cytomegalovirus; Viral infection; Peroxisomes; Innate immunity; MAVS; E5; vMIA

Upon viral infection, the host cells recognize the pathogen and activate their immune system to attempt its elimination. The Human papillomavirus (HPV) and Human cytomegalovirus (HCMV) encode several proteins, among which E5 and vMIA, respectively, which affect or even inhibit the host immune response. In this work, our main goal was to further examine their influence on the peroxisome-dependent antiviral signalling. HCMV vMIA is a protein with anti-apoptotic activity, which has also been shown to suppress the MAVS-mediated antiviral signalling at the peroxisomes and mitochondria and to induce fragmentation of both organelles. In the present work, we proposed to analyse the domains of vMIA responsible for the inhibition, complementing previous studies showing that the deletion mutants Δ2-23, Δ23-34, Δ115-130 and Δ131-147 inhibited signalling in a similar way as the wild-type. Our results indicate that vMIA Δ35-109 also suppresses the peroxisome-dependent antiviral pathway, which suggests that distinct domains act independently on the pathway or that either one of the segments maintained in all mutants (aa 110 to 114 and 148 to 163) are responsible for this role of vMIA. In addition, we have optimized a protocol for the analysis of MAVS oligomerization using semi-denaturing detergent agarose gel electrophoresis (SDD-AGE) and non-reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). These analyses would indicate whether the vMIA mutants block MAVS oligomerization, which occurs upon stimulation of the antiviral pathway. Regarding HPV, a recent study suggesting an interaction between the E5 protein and MAVS led us to direct our practical research towards the examination of their relationship. For our studies, we developed a plasmid encoding HPV16 E5 with a FLAG tag. However, regardless of our efforts it has not been possible to detect its transfection thus far, which has hindered the possibility of performing the studies proposed