Fig. 1.

Primer extension to identify a transcription start point for the cold shock gene cspA. a The lanes for each of the specific nucleotide bases of the cspA sequence are labeled G, A, T, C. P Ex identifies the primer extension fragments. The putative transcription start points, P1 (−112 bp), P2 (−88) and P3 (−51) are labeled with bold letters and numbers. Brackets indicate the cDNA primer extension fragments. b The 238 bp sequence used to identify the locations for the P1 (−112 bp), P2 (−88) and P3 (−51) TSP. Each proposed TSP is labeled and the corresponding nucleotide is in bold red and underlined. The 5′ and 3′ primers are in capital letters and underlined. The translation start codon for cspA is in bold green and a ribosomal binding site is in bold blue. The putative −10 and −35 RNA polymerase binding sites are labeled and the sequence is in bold black and underlined. The proposed binding sites, CCAAT and TTTTTT, for a cold shock protein are labeled in bold purple and bold orange, respectively and underlined. c The putative promoter sequences for each of the putative TSPs. Each sequence is identified by P1, P2 and P3 on the left, the putative TSP in bold red at the 3′ end, and sequence location in parentheses at the right. The putative −35 and −10 sequences are labeled and in bold black underlined letters. Space has been added in the P1 and P2 sequences to align the −10 sites