Identification of differentially expressed genes during its intracellular growth in .

grows intracellularly in free-living amoeba as well as in mammalian macrophages. Until now, the overall gene expression pattern of intracellular in was not fully explained. Intracellular bacteria are capable of not only altering the gene expression of its host, but it can also regulate the expression of its own genes for survival. In this study, differentially expressed genes within during the 24 h intracellular growth period were investigated for comparative analysis. RNA sequencing analysis revealed 3,003 genes from the intracellular . Among them, 115 genes were upregulated and 1,676 genes were downregulated more than 2 fold compared to the free . Gene ontology (GO) analysis revealed the suppression of multiple genes within the intracellular , which were categorized under 'ATP binding' and 'DNA binding' in the molecular function domain. Gene expression of alkylhydroperoxidase, an enzyme involved in virulence and anti-oxidative stress response, was strongly enhanced 24 h post-intracellular growth. Amino acid ABC transporter substrate-binding protein that utilizes energy generation was also highly expressed. Genes associated with alkylhydroperoxidase, glucose pathway, and Dot/Icm type IV secretion system were shown to be differentially expressed. These results contribute to a better understanding of the survival strategies of intracellular within .