PT  - JOURNAL ARTICLE
AU  - Prichard, Amy
AU  - Sy, Annika
AU  - Meyer, Justin
AU  - Villa, Elizabeth
AU  - Pogliano, Joe
TI  - Asesino: a nucleus-forming phage that lacks PhuZ
AID  - 10.1101/2024.05.10.593592
DP  - 2024 Jan 01
TA  - bioRxiv
PG  - 2024.05.10.593592
4099  - http://biorxiv.org/content/early/2024/05/11/2024.05.10.593592.short
4100  - http://biorxiv.org/content/early/2024/05/11/2024.05.10.593592.full
AB  - As nucleus-forming phages become better characterized, understanding their unifying similarities and unique differences will help us understand how they occupy varied niches and infect diverse hosts. All identified nucleus-forming phages fall within the proposed Chimalliviridae family and share a core genome of 68 unique genes including chimallin, the major nuclear shell protein. A well-studied but non-essential protein encoded by many nucleus-forming phages is PhuZ, a tubulin homolog which aids in capsid migration, nucleus rotation, and nucleus positioning. One clade that represents 24% of all currently known chimalliviruses lacks a PhuZ homolog. Here we show that Erwinia phage Asesino, one member of this PhuZ-less clade, shares a common overall replication mechanism with other characterized nucleus-forming phages despite lacking PhuZ. We show that Asesino replicates via a phage nucleus that encloses phage DNA and partitions proteins in the nuclear compartment and cytoplasm in a manner similar to previously characterized nucleus-forming phages. Consistent with a lack of PhuZ, however, we did not observe active positioning or rotation of the phage nucleus within infected cells. These data show that some nucleus-forming phages have evolved to replicate efficiently without PhuZ, providing an example of a unique variation in the nucleus-based replication pathway.Competing Interest StatementJ.P. has an equity interest in Linnaeus Bioscience Incorporated and receives income. The terms of this arrangement have been reviewed and approved by the University of California, San Diego, in accordance with its conflict-of-interest policies.