Mycobacteriophage are viruses that infect Mycobacterium, including nonpathogenic M. smegmatis and pathogenic M. tuberculosis (1). Their genomes are diverse and the majority of their genes have no known function (1). Mycobacteriophage Ukulele was isolated from soil in Old Orchard Beach, Maine. Ukulele is temperate, carrying out both lysogenic and lytic lifestyles (8). Temperate phage typically encode integrase, excise, and repressor proteins, which regulate the change from lysogenic to lytic growth (10). Ukulele gp49 has been identified as the integrase but repressor and excise proteins have not been identified (8). Ukulele gp52 was previously proposed as a candidate repressor, predicted to encode a DNA binding domain and upstream of the integrase (8). Analyzing Ukulele-M. smegmatis lysogen gene expression profiles suggests that gp52 does not serve as the repressor, and is more likely excise or a Cro-like protein. Transcriptome analysis also revealed that the lytic growth is highly induced during lysogeny, many lytic genes present in the Ukulele lysogen expression profile; which is also evidenced by the high titer 1E10 PFUs/ml for Ukulele M. smegmatis lysogens when incubated at 37 oC (8). To confirm the function of gp52, a strain of M. smegmatis will be created that over expresses Ukulele gp52. If gp52 has Cro or excise function, overexpression of gp52 in Ukulele-infected M. smegmatis cells will alter Ukulele plaque morphology. It is also recommended that RNA be isolated from Ukulele M. smegmatis lysogens at a lower temperature to increase lysogen stability (8), and reduce lytic induction.
Soohey, Robert Levi, "Identifying Genes Essential for Lysogeny in Cluster E Mycobacteriophage Ukulele" (2017). Honors College. 262.