Extracellular Contractile Injection Systems (eCIS) - Characterization of Conserved Phage Tail-like Structures in Streptomyces

Extracellular contractile injection systems (eCIS) are bacteriophage tail-like structures produced by bacteria that have been implicated in diverse interactions with eukaryotic cells. Despite their distribution across many bacteria and archaea they have been relatively understudied and are often misclassified as other secretion systems or tailocins. In this work I performed a comprehensive analysis of eCIS across bacterial genomes. I show that all eCIS are comprised of nine core protein families and are closely related to contractile phage tails, a relationship emphasized by the discovery of rare eCIS-like prophages that are the likely evolutionary link between the two. I classify eCIS into six distinct groups and show that group 1 eCIS are ubiquitous in the Streptomyces genus, where their production is linked to the developmental program of these complex filamentous bacteria. The eCIS of Streptomyces coelicolor are natively produced as intracellular phage tail-like structures. Mutations that abrogate eCIS formation cause developmental defects and reduced levels of hyphal cell death at specific times during differentiation that correlate with maximal eCIS production, suggesting a potential role in programmed cell death.

Department dc:contributor.department

Biochemistry

Year dc:date.issued

2021

Author dc:creator

• Vladimirov, Maria

Advisor dc:contributor.advisor

• Davidson, Alan AD

• phage
• programmed cell death
• secretion system
• Streptomyces
• tape measure protein

Handle dc:identifier.uri

http://hdl.handle.net/1807/106318

OAI identifier oai:identifier

oai:utoronto.scholaris.ca:1807/106318