The lytic bacteriophage T4 employs multiple phage-encoded early proteins to takeover the host. However， the functions of many of these proteins are not known. In this study， we have characterized the T4 early gene ， located in a dispensable region of the T4 genome. We show that heterologous production of MotB is highly toxic to ， resulting in cell death or growth arrest depending on the strain and that the presence of increases T4 burst size 2-fold. Previous work suggested that affects middle gene expression， but our transcriptome analyses of T4 vs. T4 wt infections reveal that only a few late genes are mildly impaired at 5 min post-infection， and expression of early and middle genes is unaffect... More
The lytic bacteriophage T4 employs multiple phage-encoded early proteins to takeover the host. However， the functions of many of these proteins are not known. In this study， we have characterized the T4 early gene ， located in a dispensable region of the T4 genome. We show that heterologous production of MotB is highly toxic to ， resulting in cell death or growth arrest depending on the strain and that the presence of increases T4 burst size 2-fold. Previous work suggested that affects middle gene expression， but our transcriptome analyses of T4 vs. T4 wt infections reveal that only a few late genes are mildly impaired at 5 min post-infection， and expression of early and middle genes is unaffected. We find that MotB is a DNA-binding protein that binds both unmodified host and T4 modified [(glucosylated， hydroxymethylated-5 cytosine， (GHme-C)] DNA with no detectable sequence specificity. Interestingly， MotB copurifies with the host histone-like proteins， H-NS and StpA， either directly or through cobinding to DNA. We show that H-NS also binds modified T4 DNA and speculate that MotB may alter how H-NS interacts with T4 DNA， host DNA， or both， thereby improving the growth of the phage.
