The effects of SARS-CoV-2 protein Nsp1 on translation in human cells

Severe acture respiratory syndrome coronavirus 2 (SARS-CoV-2) je koronavirus koji uzrokuje teške respiratorne probleme kod ljudske populacije i uzrok je trenutne pandemije. Zbog toga postoji potreba za istraživanjem mehanizma infekcije virusa kako bi se mogle utvrditi potencijalne mete terapeutika. U ovom radu istražena je uloga proteina Nsp1 virusa SARS-CoV-2 korištenjem dvostrukog sustava proteina reportera luciferaze. Protein Nsp1 je jedan od proteina koji su eksprimirani u najranijim fazama infekcije virusom te se pretpostavlja kako ima ulogu u inhibiciji translacije. Ovaj rad pokazuje da protein Nsp1 ima sposobnost selektivnog odabira virusnih transkripata od staničnih te samo za njih omogućuje translaciju, dok za stanične transkripte istu inhibira. Također, pokazano je da je za proces prepoznavanja bitna uloga 5' vodeće virusne sekvence i da su aminokiseline na mjestima RK124 i KH164 esencijalne za funkcionalnost proteina. Nadalje, ovaj rad pokazuje da postoji očuvanje funkcije između proteina Nsp1 virusa SARS-CoV-2 i homolognog proteina virusa SARS-CoV-1 (severe acture respiratory syndrome 1). Zajedno ovi rezultati ukazuju na važnost proteina Nsp1 u virusnoj infekciji i naglašavaju ulogu u progresiji bolesti.Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a coronavirus that causes severe respiratory issues in the human population and is the reason behind the ongoing pandemic. Because of that, there is a worldwide need to decipher its mechanisms of infection in order to be able to determine potential therapeutics targets. In this thesis, the role of the SARS-CoV-2 protein Nsp1 is explored using a dual luciferase reporter assay approach. Nsp1 is one of the earliest viral proteins expressed upon infection and it is presumed to have a role in inhibiting translation. This thesis shows that Nsp1 selects and allows translation of viral transcripts and blocks translation of cellular transcripts. Another finding is that the 5’ viral leader sequence is essential for this recognition process and that the amino acid sites RK124 and KH164 are essential for the protein’s functionality. In addition, it is shown that there is conservation of function between SARS-CoV-2 Nsp1 and its homolog from SARS-CoV-1 (severe acture respiratory syndrome coronavirus 1). Together, the results indicate the importance of Nsp1 in viral infection and emphasise its role in disease progression