Determination of ftsZ, ftsA and ftsQ RNA 5’ ends by primer extension (PE) in B. mycoides SIN (S) and DX (D). 5’ 32P-labeled primers were hybridized to total RNA, extended by reverse transcriptase and the cDNAs separated by 6% urea-PAGE electrophoresis. The numbers on the right side of the autoradiograms indicate the position of the cDNA 3’ ends relative to the ORF first nucleotide (+1). The thick lateral bar indicates the approximate position in the gel of the next upstream gene. A) PE from primer ZB annealing to ftsZ RNA at +103; B) PE from primer Arev annealing to ftsA RNA at +80; C) PE from primer Qrev annealing to ftsQ RNA at +52 (Table 1). Here two different SIN cDNA preparations were loaded on the gel. A schematic view of the major cDNA products is shown in the inset. M = MW marker 32P-labeled DNAs. GATC = 35S-dATP labeled M13mp18 ladder.