A phage-encoded metallophosphoesterase determines the viral host range and is essential for escaping the anti-phage defense of Mycobacterium tuberculosis

The molecular mechanism by which a mycobacterial virus escapes the host bacterial defense and kills the human pathogen Mycobacterium tuberculosis is greatly unclear. Here we report that the gene gp48 of mycobacteriophage A4ZJ24, encoding a metallophosphoesterase-like protein, is required for the killing of M. tuberculosis, but not for M. smegmatis. Gp48 is expressed in the early stage of phage infection and disrupts the mycobacterial chromosomal DNA, and thus silences the expression of multiple anti-phage defensive genes, which only exist in the genome of M. tuberculosis but not in M. smegmatis. The gp48-deleted phage can normally adsorp and invade into M. tuberculosis, however, it does not prevent from activating anti-phage genes, resulting in a loss of its genome DNA replication ability in M. tuberculosis. This study identifies a phage's metallophosphoesterase as a new determinant of the viral host range and discovered a previously unknown molecular mechanism for mycobacteriophages to kill M. tuberculosis. Our study fills a major gap in current knowledge of the interaction between mycobacterial viruses and M. tuberculosis. Overall design: To investigate the changes in gene expression levels of mycobacterium tuberculosis during infection with A4ZJ24 phage and gp48-deleted mutant phage, we used two mycobacteriophage to infect M. tuberculosis, and the samples were taken at 1h or 10h after infection. We then performed gene expression profiling analysis using data obtained from RNA-seq of 2 samples at two different time points. Comparative gene expression profiling analysis of RNA-seq data for A4ZJ24 WT and A4ZJ24 ?gp48.