sentence: We used lacZ as a reporter gene , to measure the activity of M. tuberculosis promoters thought to be regulated by PhoP in M. smegmatis , a non pathogenic and fast-growing mycobacterial species.Several fragments corresponding to upstream and structural gene regions of pks2 ( − 86 , +60 ) , msl3 ( − 282 , +28 ) and fadD21 ( − 198 , +10 ) were generated ( Table 1 ) .