MtbRho is specific to <i>M. tuberculosis.</i>

<p>(A) Complementation of <i>E.coli</i> AMO14 strain attempted with Mtb <i>rho</i>. Transformants harbouring pTrc99C or pTrc99C-<i>Mtbrho</i> were grown to OD₆₀₀ 0.6 at 30°C, streaked on IPTG- containing plates and incubated at permissive (30°C) or non-permissive (42°C) temperature. Untransformed cells(1,4); transformants with pTrc99C (2,5); transformants with pTrc99C-<i>Mtbrho</i>(3,6).(B) Expression of MtbRho and ΔNTS-MtbRho in <i>E.coli</i> AMO14 transformants when induced with 0.3 mM IPTG at permissible temperature. (C) MtbRho terminates transcription by <i>E. coli</i> RNAP <i>in vitro</i>. Run-off transcript (RO) was reduced and several smaller transcripts appeared when transcription was done in presence of MtbRho (Mtb; lane 2) compared to that in absence of MtbRho (C; lane 1). The effect was reversed when MtbRho has been pre-incubated with 400 or 500 µM bicyclomycin (400,500; lanes 3, 4). EcRho also caused termination (Ec; lane 5), at a different region of transcript. The terminated transcripts are indicated with dashed lines.