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

The T4 polynucleotide ligase catalyzed joining of six chemically synthesized deoxypolynucleotides corresponding to lactose operator DNA has been 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 one strand of operator DNA required several days and repeated annealing in order to go to completion. These studies have permitted the synthesis on a preparative scale (several nanomoles) of operator duplexes and operator single strands.