FIG. 3.
Effects of heterologous and homologous RepA-CIS combinations and C-terminal deletions in RepA on the copy number of oriB and oriL plasmids. Copy number was determined by assaying the CAT activity of E. coli strain JP3438 carrying the ori plasmids, in the absence of IPTG. The values shown are the average of at least six independent determinations. NR, ori plasmid unable to replicate without the induction of the pAM34 replicon; H, copy number too high to be determined accurately; →, RNA transcript.