cre sequence alignment. (A) Structure of the groESL and dnaK promoter regions. The positions of the putative cre sequences upstream of the promoters are shown. (B) Comparison of cre box consensus sequence  with dnaK and groESL putative cre box sequences. Symbols for nucleotides in the consensus sequence: W (A or T); R (A or G); N (A, G, C or T).