Roles Of GroEL And MreB Of Geobacillus Sp.E263in The Infection Of Thermophilic Bacteriophage GVE2

The life cycle of a bacteriophage has tightly programmed steps to help virus infect its host through the interactions between the bacteriophage and its host proteins. However, bacteriophage-host protein interactions in high temperature environment remain poorly understood. Studies on thermophilic bacteriophage are not only helpful for understanding the control of deep sea hydrothermal vent biological environments, but also of great potential for ocean resource development and exploring the origin of life.To address these issues, the protein interactions between the thermophilic bacteriophage GVE2and its host thermophilic Geobacillus sp. E263from a deep-sea hydrothermal vent was characterized. This investigation showed that the host’s aspartate aminotransferase (AST), chaperone GroEL, and viral capsid protein VP371formed a linearly interacted complex. The results indicated that the VP371-GroEL-AST complex were up-regulated and co-localized in the GVE2infection of Geobacillus sp. E263. It could be inferred that the interaction between the host GroEL and the viral VP371proteins facilitated the synthesis of the major capsid protein VP371in the GVE2bacteriophage life cycle. In addition, GroEL in the host cells could facilitate the correct folding of host AST, which provided more effective amino acid metabolism to ensure the protein synthesis of bacteriophages in high temperature environment.In eukaryotes, the manipulation of the host actin cytoskeleton is a necessary strategy for viral pathogens to invade host cells. Increasing evidence indicates that the actin homolog MreB of bacteria plays key roles in cell shape formation, cell polarity, cell wall biosynthesis, and chromosome segregation. However, the role of bacterial MreB in the bacteriophage infection is not extensively investigated. To address this issue, in this study the MreB of thermophilic Geobacillus sp. E263from a deep-sea hydrothermal field was characterized by inhibiting MreB polymerization and subsequently evaluating the bacteriophage GVE2infection. The results showed that the host MreB played important roles in the bacteriophage infection at high temperature. After the host cells were treated with A22or MP265, the specific inhibitors of MreB, the adsorption of GVE2and the replication of GVE2genome were significantly repressed. The confocal microscopy data revealed that MreB facilitated GVE2infection by inducing the polar distribution of virions during phage infection.Therefore, our study revealed that the phage could use the MreB cytoskeleton system and anti-stress system of its host to protect the virus reproduction in a high-temperature environment for the first time and contributed novel information to understand the molecular events of the host in response to bacteriophage challenge and extended our knowledge about the host-virus interaction in deep-sea vent ecosystems.