Horbach E, Müller-Hill B
Institut für Genetik der Universität zu Köln, F.R.G.
J Mol Biol. 1988 Jul 5;202(1):157-60. doi: 10.1016/0022-2836(88)90527-x.
Plasmids that contain a d(pCpG)13.d(pCpG)13 insert instead of a lac operator show a 34-fold decrease of beta-galactosidase synthesis. The same sequence causes a 24-fold decrease when inserted between codons 5 and 6 of the lacZ gene. In such constructs with d(pCpG)n.d(pCpG)n inserts, beta-galactosidase activity decreases approximately 1.6-fold per d(pCpG).d(pCpG) unit when n ranges from 5 to 16.