First evidence of host range expansion in virophages and its potential impact on giant viruses and host cells

Said Mougari; Nisrine Chelkha; Dehia Sahmi-Bounsiar; Fabrizio Di Pinto; Philippe Colson; Jonatas Abrahao; Bernard La Scola

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/780841 doi: bioRxiv preprint virophage. Host acquisition was associated with the emergence of a new genotype of Guarani that showed deletion of an 81-nucleotide long sequence from ORF8 that encodes a collagen repeat-containing protein. We found that despite this deletion, the virophage was still able to replicate with its previous virus hosts without any fitness change (Fig. 3c) . One might suppose that this replication has been observed because of the presence of a background of wild-type virophage. However, almost pure mutant Guarani (isolated from passage 5 with Tupanvirus as shown in Fig. 4a) Therefore, it is possible that the mutant genotype was already present in the Guarani population that seemed not able to replicate with Tupanvirus. However, its concentration was probably under the limit of detection of our systems. Then, Tupanvirus allowed the selection of the mutant in coinfected cells. The presence of a very low amount of the mutant virophage after the first passage with Tupanvirus probably supports this hypothesis (Fig. 4a, arrow) .