Mapping of transcription start site (TSS) in mce1 operon. A -Line diagram indicating the position of primers used for mapping TSS by primer extension. The numbers in parenthesis indicate the map position on the reference sequence of M.tubersulosis H37Rv. Filled boxes indicate non-coding regions, filled arrowheads indicate translation start site, tsp1 is HEX-labeled primer beginning at 195092, tsp2 is FAM-labeled primer beginning at 196960. P1 and P2 represent the TSS detected. B-E show Genescan analysis of the products of primer extension reactions on mRNA from M.tuberculosis H37Rv (B, D) and VPCI591 (C, E) with fluorescence labeled primers is shown in A. The peak at 165 bp position is transcript from P1 promoter and the peak at 156 position transcript from P2 promoter.