Influenza A virus causes acute respiratory infection in humans, which manifests by varying severity ranging from asymptotic infection to fatal disease. High mutation rates and frequent genetic reassortments of these viruses cause variability of envelope glycoproteins requiring continuous development of new antiviral drugs. The influenza A virus genome is composed of 8 segments of negative-sense, single stranded RNA bound to numerous copies of N-protein. In order to maturate to a functional virus particle, individual ribonucleoprotein (RNP) segments have to package in certain order. Alteration of genome packaging could thus cause alternative strategy for treatment of influenza A virus infections. The topic of the theses is to study the mechanism of genome packaging for individual segments of influenza A virus by combination of molecular biology methods together with structural characterization by electron cryo-microscopy (cryoEM). The selected segments will be tagged with the selected proteins in order to make it distinguishable for cryoEM. In order to observe genome packaging directly inside the eukaryotic cells, the focused ion beam (FIB) will be used to remove the redundant cell material and make the regions of interest transparent for cry-electron tomography experiments.