The addition of Gene 7.5 to the Genome of ThreerngTarjay

Craig, Griffin, Jones Marcel, Stephanie B. Conant, Jonathan S. Finkel, and Jacob D. Kagey

Bacteriophages have the potential to be used in phage therapy to treat diseases caused by bacteria. This is an improvement over antibiotics, as bacteriophages target bacteria with a high specificity while antibiotics kill bacteria indiscriminately, including those that are beneficial to humans. Additionally, bacteria are becoming increasingly resistant to antibiotics, making an alternative method to combat common diseases necessary. Phages that infect the mycobacterium smegmatis are sequenced often in order to help determine the functions of their genes and how different phages are related. M. smegmatis is used because of its close relation to the mycobacterium tuberculosis. This research could help to develop a phage therapy that is effective against tuberculosis, saving many lives. The mycobacteriophage ThreeRngTarjay was isolated from a soil sample, purified, and then sequenced so that more could be learned about it. ThreeRngTarjay was chosen for sequencing because it switches between lytic and lysogenic life cycles, causing it to form unique target shaped plaques. Determining which gene causes ThreeRngTarjay to switch between lytic and lysogenic lifecycles would be useful, as lysogenic phages are unsuitable for phage therapy due to the amount of time they can take to kill bacteria. This would make the creation of phage therapies simpler. ThreeRngTarjay was annotated using the program DNA master. During the annotation process it was discovered that DNA master had failed to identify a gene. While programs like DNA master are immensely useful in speeding up the annotation process, they occasionally make mistakes, necessitating manual annotation. The discovered gene was found by the protein BLAST program to be present in other closely related bacteriophages. Discovering the presence of this gene is important, as it could be responsible for ThreeRngTarjay alternating between lytic and lysogenic life cycles, or be vital to ThreeRngTarjay’s survival.