A Toxic Ride Through the Pumpkin Patch: Identification of Cytotoxic Genes in Mycobacteriophage Pumpkin

Student Author(s)

Eric Cox

Faculty Mentor(s)

Dr. Joseph Stukey; Dr. Virginia McDonough

Document Type


Event Date



Mycobacteriophages are viruses that infect mycobacterium host cells. With more than 200 mycobacteriophage genomes sequenced and available in GenBank, they represent the largest collection of sequenced phages that infect a single host (Mycobacterium smegmatis). Surprisingly however, they are genetically diverse and contain many genes of unknown function. This fact begs the question of how the different mycobacteriophages accomplish the host-cell takeover that supports infection and phage propagation. One way to tackle this problem is to first identify phage genes that are cytotoxic when expressed individually in the host cell. We hypothesize that cytotoxic phage genes will encode proteins that interact with and affect the function of critical host cell proteins. We are using this approach on a mycobacteriophage called Pumpkin, which was isolated at Hope College in 2008. We have identified a small genomic region, encompassing genes gp115-120 that is cytotoxic to M. smegmatis. Subsequent division of this region further identified gp115 and the region gp117-120, possibly centered on gp119, as possessing cytotoxic activity. Neither gp115 nor gp119 from mycobacteriophage Pumpkin have assigned functions and appear to only match other mycobacteriophage proteins. Future work will include further testing of individual genes in this region.

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