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-Structure paper
Title | Identifying the core genome of the nucleus-forming bacteriophage family and characterization of phage RAY. |
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Journal, issue, pages | bioRxiv, Year 2023 |
Publish date | Feb 25, 2023 |
PubMed Abstract | We recently discovered that some bacteriophages establish a nucleus-like replication compartment (phage nucleus), but the core genes that define nucleus-based phage replication and their phylogenetic ...We recently discovered that some bacteriophages establish a nucleus-like replication compartment (phage nucleus), but the core genes that define nucleus-based phage replication and their phylogenetic distribution were unknown. By studying phages that encode the major phage nucleus protein chimallin, including previously sequenced yet uncharacterized phages, we discovered that chimallin-encoding phages share a set of 72 highly conserved genes encoded within seven distinct gene blocks. Of these, 21 core genes are unique to this group, and all but one of these unique genes encode proteins of unknown function. We propose that phages with this core genome comprise a novel viral family we term Chimalliviridae. Fluorescence microscopy and cryo-electron tomography studies of phage vB_EamM_RAY confirm that many of the key steps of nucleus-based replication encoded in the core genome are conserved among diverse chimalliviruses, and reveal that non-core components can confer intriguing variations on this replication mechanism. For instance, unlike previously studied nucleus-forming phages, RAY doesn't degrade the host genome, and its PhuZ homolog appears to form a five-stranded filament with a lumen. This work expands our understanding of phage nucleus and PhuZ spindle diversity and function, providing a roadmap for identifying key mechanisms underlying nucleus-based phage replication. |
External links | bioRxiv / PubMed:36865095 / PubMed Central |
Methods | EM (subtomogram averaging) |
Resolution | 8.9 - 38.0 Å |
Structure data | EMDB-27973: Erwinia amylovora 70S Ribosome EMDB-27993: Erwinia amlyavora 50S ribosome EMDB-28003: Erwinia phage vB_EamM_RAY (RAY) Capsid Vertex EMDB-28004: Erwinia phage vB_EamM_RAY (RAY) Capsid Collar EMDB-28005: Erwinia phage vB_EamM_RAY (RAY) Tail Sheath EMDB-28006: Erwinia phage vB_EamM_RAY (RAY) Baseplate EMDB-28007: Erwinia phage vB_EamM_RAY (RAY) Chimallin EMDB-28008: Erwinia phage vB_EamM_RAY (RAY) Putative PhuZ Filament EMDB-28009: Pseudomonas chlororaphis phage 201phi2-1 PhuZ Filament EMDB-28010: Pseudomonas phage phiKZ PhuZ Filament |
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