Project Details
Projekt
Regulation of host protein synthesis by jumbo phage proteins
Applicant
Professor Dr. Jörg Vogel
Subject Area
Medical Microbiology and Mycology, Hygiene, Molecular Infection Biology
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 465133664
Phages with large genomes and complex lifestyles represent exciting opportunities to discover new molecular factors and principles of host manipulation. Most of the proteins encoded by these phage genomes have no matches in the current sequence databases, promising a vast untapped discovery space for new proteins with specialized functions. The functional analysis of phage proteins and host defence systems has already provided invaluable molecular tools such as T7 polymerases, T4 kinases, restriction enzymes, phage display and CRISPR-Cas technology. Moreover, the analysis of phage-host interactions on the molecular level has led to a better understanding of the basic principles of gene expression. Finally, phages represent a resource for the discovery of novel bactericidal proteins that could be used as antibiotics to control multidrug-resistant human pathogens. Our model system is the jumbo phage ΦKZ that infects Pseudomonads. Its 280-kB genome encodes for >369 annotated open reading frames of which most remain uncharacterised. We established an integrative high-throughput approach called Grad-seq to uncover phage-encoded proteins that target the gene expression machinery of Pseudomonas aeruginosa upon infection with ΦKZ. Strikingly, we found many phage proteins that associate with large protein complexes in the host, e.g. the RNA polymerase or ribosomes. Through biochemical, genetic, and structural analyses, we identified the abundant and conserved phage protein ΦKZ014 and showed that it directly targets translating ribosomes. ΦKZ014 is among the earliest ΦKZ proteins expressed after infection. We have also identified specific Pseudomonas strains in which ΦKZ014 is essential for productive phage replication. These strains lend themselves as genetic systems for the functional dissection of ΦKZ014. We aim to characterize the molecular mechanisms employed by ΦKZ to manipulate the host translation machinery and to promote viral replication. In addition, we want to identify the anti-phage defence system that is bypassed by ΦKZ014. Overall, our analysis will provide us with a better understanding of how phages take control of the bacterial host cell at the level of translation and how bacteria fight back, allowing us to establish a new link between translation and bacterial immunity.
DFG Programme
Priority Programmes
