| Abstract: | With unprecedented particle and genome sizes, the recently discovered virus Mimivirus is by far the largest virus heretofore identified, blurring the established division between viruses and single-cell organisms. Such unusual parameters raise fundamental questions related to physical and biophysical aspects of viral infection. These include the mechanisms that promote entry of viral genomes into host cells and trafficking within the highly crowded host cytoplasm, virion assembly and genome packaging. Our structural studies indicate that in contrast to all other DNA viruses, the Mimivirus releases its genome into the host cytoplasm in a single step that is promoted by a large-scale conformational change of the viral capsid. This process is followed by the assembly of a highly-ordered viral factory, within which multiple progeny are rapidly generated. The various transactions that occur in the viral factory are exquisitely coordinated in time and space, thus providing an exciting case study in self-assembly. The physical and evolutionary implications of these findings will be discussed. |
