The proteomics of the giant cedratvirus particles reveals unique and shared features with pitho-like viruses

Cedratvirus is a giant virus belonging to the order Pimascovirales, a group that includes other viruses such as pithoviruses and orpheoviruses. Cedratviruses infect Acanthamoeba castellanii and have a genome of ~600 kb, encoding ~800 predicted proteins. In this study, we performed, for the first time to our knowledge, a proteomic analysis of purified cedratvirus particles, identifying 266 proteins associated with the virus. These proteins were involved in a variety of cellular processes, including signal transduction regulation, transcription, RNA processing, DNA replication, recombination, and repair, among others. Additionally, we identified in cedratvirus particles 172 host-associated proteins. A comparative analysis of the cedratvirus proteome with that of pithovirus sibericum revealed that 89 proteins are shared between the two viruses, while 96 proteins are unique to cedratvirus. These findings provide the first comprehensive proteomic characterization of a cedratvirus, advancing our understanding of its molecular biology and highlighting both conserved and unique features within the pimascoviruses, which may inform future studies on viral evolution and host-virus interactions.

There are still only a few studies on the proteomics of giant viruses. Research published to date has revealed the presence of several proteins involved in processes such as transcription (including RNA polymerase subunits, helicases, and transcription factors), DNA topology regulation (e.g., topoisomerases), and metabolic pathways (e.g., enzymes that help the virus cope with host oxidative stress). Proteomic studies of giant viruses are important, as understanding the role of these proteins can provide information about viral biology, host-virus interactions, and viral evolution. Here, we present, for the first time to our knowledge, a proteomic analysis of a cedratvirus, highlighting unique and shared features with pithovirus, a relative.