Cedratvirus getuliensis replication cycle: an in-depth morphological analysis

The giant viruses are the largest and most complex viruses in the virosphere. In the last decade, new members have constantly been added to this group. Here, we provide an in-depth descriptive analysis of the replication cycle of Cedratvirus getuliensis, one of the largest viruses known to date. We tracked the virion entry, the early steps of virus factory and particles morphogenesis, and during this phase, we observed a complex and unique sequential organization of immature particle elements, including horseshoe and rectangular compartments, revealed by transverse and longitudinal sections, respectively, until the formation of the final ovoid-shaped striped virion. The genome and virion proteins are incorporated through a longitudinal opening in the immature virion, followed by the incorporation of the second cork and thickening of the capsid well. Moreover, many cell modifications occur during viral infection, including intense membrane trafficking important to viral morphogenesis and release, as evidenced by treatment using brefeldin A. Finally, we observed that Cedratvirus getuliensis particles are released after cellular lysis, although we obtained microscopic evidence that some particles are released by exocytosis. The present study provides new information on the unexplored steps in the life cycle of cedratviruses.