A Phage Tubulin Assembles Dynamic Filaments by an Atypical Mechanism to Center Viral DNA within the Host Cell

• Published in: Cell Vol. 149; no. 7; pp. 1488 - 1499
• Main Authors: Kraemer, James A., Erb, Marcella L., Waddling, Christopher A., Montabana, Elizabeth A., Zehr, Elena A., Wang, Hannah, Nguyen, Katrina, Pham, Duy Stephen L., Agard, David A., Pogliano, Joe
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 22.06.2012
• Subjects: Amino Acid Sequence; bacteria; bacteriophages; Bacteriophages - physiology; cytoskeleton; Cytoskeleton - metabolism; DNA; DNA, Viral - metabolism; eukaryotic cells; Guanosine Diphosphate - metabolism; Models, Molecular; Molecular Sequence Data; polymerization; Pseudomonas - cytology; Pseudomonas - virology; reproduction; Sequence Alignment; tubulin; Tubulin - chemistry; Tubulin - genetics; Tubulin - metabolism; Viral Proteins - chemistry; Viral Proteins - genetics; Viral Proteins - metabolism
• ISSN: 0092-8674; 1097-4172
• DOI: 10.1016/j.cell.2012.04.034

Tubulins are essential for the reproduction of many eukaryotic viruses, but historically, bacteriophage were assumed not to require a cytoskeleton. Here, we identify a tubulin-like protein, PhuZ, from bacteriophage 201φ2-1 and show that it forms filaments in vivo and in vitro. The PhuZ structure has a conserved tubulin fold, with an unusual, extended C terminus that we demonstrate to be critical for polymerization in vitro and in vivo. Longitudinal packing in the crystal lattice mimics packing observed by EM of in-vitro-formed filaments, indicating how interactions between the C terminus and the following monomer drive polymerization. PhuZ forms a filamentous array that is required for positioning phage DNA within the bacterial cell. Correct positioning to the cell center and optimal phage reproduction only occur when the PhuZ filament is dynamic. Thus, we show that PhuZ assembles a spindle-like array that functions analogously to the microtubule-based spindles of eukaryotes. [Display omitted] ► Identification of a family of tubulins, PhuZ, encoded by bacteriophage ► PhuZ forms a spindle-like structure that centers phage DNA and optimizes phage production ► PhuZ crystal structure reveals an extended C terminus and lack of conserved helix 6 ► PhuZ C-terminal interactions are required for polymerization in vivo and in vitro A tubulin-like protein found in a bacteriophage virus forms long filaments that center phage DNA within infected bacterial cells. Loss of these filaments, which are reminiscent of a eukaryotic spindle, reduces phage burst size, suggesting that localized production of virus improves its fitness/infectivity.