Figure 4

BioBrick™ promoters characterization, expressed in Relative Promoter Units, in single chromosomal copy (Ф80 and aspA loci) and in low-copy context (pSB4C5 vector). Promoter activity was measured via the BBa_I13507 (RBS BBa_B0034-mRFP1-double terminator) part. Grey bars represent the average values, computed on at least five clones, and the error bars represent the 95% confidence intervals. For each promoter, statistical analysis was performed via ANOVA test to compare the RPU activities measured in the three different contexts. Conditions showing a statistical difference (P < 0.05) in the mean activities among the three conditions are marked with a ‘+’ sign, while promoters not showing any significant difference (P ≥ 0.05) are marked with a ‘-’ sign. Asterisks represent the post-hoc comparison results. They indicate the individual significantly different condition.