TABLE 5.

1925 and 1926 are lost more rapidly from 143/EBNA-1 cells than is oriP-Backbone over a 12-day time course

Days postelectroporation	% Relative to oriP-Backbone on day 8a
	oriP-Backbone	1925	1926
8	100 ± 31	100 ± 59	100 ± 44
12	63 ± 40	55 ± 40	40 ± 26
16	62 ± 28	18 ± 7.7	17 ± 8.0
20	48 ± 17	11 ± 1.9	14 ± 3.6

^a10 μg of each DNA (oriP-Backbone, 1925, or 1926) and oriP-minus were introduced into 10⁷ 143/EBNA-1 cells by electroporation. Low-molecular-weight DNA was isolated at 8, 12, 16, and 20 days postelectroporation, and the number of DpnI-resistant plasmids per transfected cell was determined by quantitative competitive PCR and was corrected for the transfection efficiency of 143/EBNA-1 cells as described in Materials and Methods. The efficiency of replication of each reporter is expressed as a percentage of the amount of DpnI-resistant DNA per transfected cell relative to that present at day 8 for each reporter construct. For oriP-Backbone, 1925, and 1926, 100% = 12, 2.2, and 2.5 copies of DpnI-resistant DNA per transfected cell, respectively. The level of DpnI-resistant oriP-minus DNA was less than the smallest amount used for the competitor DNA for all samples (less than 0.20 copies per transfected cell). Data represent an average of three experiments for each time point ± standard deviation.