<i>clpP1</i> and <i>clpP2</i> are co-transcribed as an operon.

<p>A) Chromosomal organisation of <i>clpP1</i> and <i>clpP2</i>. Regions amplified for RT-PCR are marked. B) Limiting dilution semi-quantitiative RT-PCR. RNA was extracted from <i>M. tuberculosis</i> grown to late exponential phase in liquid cultures and cDNA was synthesised from 1 µg of RNA. Serial 4- fold dilutions of cDNA were used as a template for PCR using primers specific for <i>clpP1</i> (P1), <i>clpP2</i> (P2), the <i>clpP1</i>-<i>clpP2</i> junction (P1P2) and <i>sigA</i>. C: no RT control; B: no template blank, M: markers.