text: Modern lacUV5 is seen in the BL21(DE3) strain, which carries both a lac operon with the standard promoter and a lacUV5 operon split by the DE3 prophage (and as a result driving the T7 RNA polymerase instead). The two important mutations are underlined.
   lacUV5  TCACTCATTAGGCACCCCAGGCTTTACACTTTATGCTTCCGGCTCGTATTGTGTGGAATTGTGAGCGGATAACAATTTCACACAGGAAACAGCT
   LacZ    TCACTCATTAGGCACCCCAGGCTTTACACTTTATGCTTCCGGCTCGTATTGTGTGAAATTGTGAGCGGATAACAATTTCACACAGGAAACAGCT
     position                     ^-35                     ^-10       ^+1