Figure 2.

Characterization of yeast constitutive promoters. (A) Five promoter regions cloned from the yeast genome give consistent expression of two fluorescent reporters. (B) Twenty-four random nucleotides are fused to the 5′ end of YFP. Notably, sequence 7 has an in-frame stop codon and a second start codon; sequence 8 has an in-frame stop codon. (C) Random nucleotide sequences do not appreciably alter YFP fluorescence (compare all bars of a single color). Additionally, the rank order of promoter strengths for a given coding sequence is maintained (compare all sets of bars for a given peptide). (D) Combinatorial assembly of promoter libraries: five promoters are combinatorially cloned in front of RFP, YFP and CFP separately (red, yellow and blue); RFP, YFP and CFP libraries are combinatorially assembled (green); empty vector (black). Error bars in panels (A) and (C) indicate s.e.m; n = 8.