Base pair requirement in gal promoters. (a) The DNA sequence from −25 to +1 and a summary of the effect of base pair change from +1 to −25 on P1 transcription. (b) The DNA sequence from −20 to +6 and a summary of the effect of base pair change from −20 to +6 on P2 transcription. (c) Consensus promoter region of P1 and P2 derived from (a) and (B). R = A or G, N = any nucleotide. Base pair is in red if it is unique for promoter function, green if it improves promoter function, and black if it is degenerate. The symbol “>>>>” in vertical shapes represents 4.1-fold or more difference in promoter function from the wild type; “>>>”, 3.1 to 4-fold; “>>”, 2 to 3-fold; “>” less than 2-fold; “=“ indicates equal.