Global expression analysis of two-component system regulator genes during Mycobacterium tuberculosis growth in human macrophages

In the Mycobacterium tuberculosis H37Rv genome, there are 11 paired two-component regulatory system genes, two orphan histidine kinase genes, and six orphan response regulator genes. Expression of the 17 response regulator genes and the two orphan histidine kinase genes during growth of M. tuberculosis in human peripheral blood monocyte-derived macrophages has been analyzed by using cDNA mixtures prepared by the selective capture of transcribed sequences (SCOTS) technique. SCOTS probes were prepared from cDNA obtained from M. tuberculosis grown for 18, 48, and 110 h in human macrophages. Based on expression profiles, the regulatory genes were assigned to three categories: (i) constitutively expressed during growth in macrophages (three genes); (ii) differentially expressed during growth in macrophages (nine genes) and (iii) no detectable expression during growth in macrophages (seven genes).