Similarity of the putative promoters regions of sigN Group 2 genes. A. The sequences of the putative promoters of sigN Group 2 genes, considered as the upstream regions from the initiation codon to the closest gene-coding region, were compared and the alignment of the regions containing putative regulatory sites is shown. The boxes in the figure indicate the possible binding sites for the transcription factor GBF (G-box Binding Factor). Pairs of contiguous binding sites have been grouped and labelled as regulatory regions A and B. Identical nucleotides are indicated in green. The level of identity between nucleotides of the different genes is represented as bars (conservation). B. Phylogenetic tree calculated from the nucleotides alignments shown in panel A using the Clustal W program. C. Schematic representation of the location of conserved, potential regulatory regions (A and B) present in the intergenic region between each pair of inverted genes, represented as rounded boxes. Coding regions are represented as boxes and intron and untranslated regions as lines. The direction of transcription of each gene is represented by arrow heads.