Figure 6

Base composition around transcription start sites. The proportions of bases from 100 bp upstream to 25 bp downstream of putative 4637 ‘tight’ transcription start sites (100-200 bp upstream shows no perturbation from the 25% expected by chance and is not shown). The region is enriched for C from approximately position -75 and for C and T from approximately position -50. A peak of A and T is seen in the region -45 to -30, which may indicate putative TATA box motifs. Nucleotide C peaks at position -1 and nucleotide A at the transcription start site, followed by C.