Studies on gene control regions. 2. Enzymic joining of chemically synthesized lactose operator deoxyribonucleic acid segments

Abstract
The [phage] T4 polynucleotide ligase catalyzed joining of 6 chemically synthesized deoxypolynucleotides corresponding to lactose operator DNA [of Escherichia coli] investigated. Joining was studied using various combinations of segments. Joining reactions involving multiple sites and the formation of duplex operator DNA were complete in a few hours. Joining reactions involving a single site and the formation of only 1 strand of operator DNA required several days and repeated annealing in order to go to completion. These studies permitted the synthesis on a preparative scale (several nanomoles) of operator duplexes and operator single strands.