Virophages are small dsDNA viruses that were first isolated in association with some giant viruses (GVs), and then found in metagenomics samples. They encode about 20⁻34 proteins. Some virophages share protein similarity with Maverick/Polinton transposons or are considered as a provirophage, whereas about half of the protein's repertoire remain of unknown function. In this review, we aim to highlight the current understanding of the biology of virophages, as well as their interactions with giant viruses and host cells. Additionally, the virophage proteomes were analyzed to find the functional domains that distinguish each virophage. This bioinformatics analysis will benefit further experimental investigations to understand the protein-protein interactions between virophages, giant viruses, and host cells.
Keywords: giant viruses; nucleocytoplasmic large DNA viruses (NCLDVs); post translational modifications; protein-protein interactions; virophage.