[1] LacUV5 is among the most commonly used promoters in molecular biology because it requires no additional activators and it drives high levels of gene expression.
[3]: 4b Due to this, lacUV5 recruits RNA Polymerase more effectively, thus leading to higher transcription of target genes.
[2] While no activators are required, lacUV5 promoter expression can be regulated by the LacI repressor and can be induced with IPTG, which is an effective inducer of protein expression when used in the concentration range of 100 μM to 1.5 mM.
[citation needed] The lacUV5 mutation was first identified in 1970 in a study of lac promoter mutants that produce higher yields.
[4] Development into cloning vectors is known since 1982, when a UV5-carrying phage known as "λ h80 lacUV5 cI857" has its genome spliced with the HaeIII restriction enzyme to make plasmids carrying the fragment with UV5.