TABLE 3.

Analyses of JZ442 PPT + 3′ Hyg on D17 cells^a

Clone	No. colonies			Rate of mutation (%)	Titer
	Green	Clear	Mix colored
Clone 1	431	1	2	0.7	0.18 × 105
Clone 2	487	1	1	0.4	1 × 105
Clone 3	761	8	1	1.2	0.25 × 105
Clone 4	782	8	5	1.6	0.27 × 105
Clone 5	564	3	1	0.7	1.2 × 105
Clone 6	172	2	0	1.2	0.34 × 105
Clone 7	289	1	0	0.5	0.57 × 105
Total	3,486	24	10	0.9 ± 0.4b	(0.54 × 105) ± (0.40 × 105)c

^aViruses from step 2 PG13 cells, which contain a gfp gene, were used to infect D17 cells. Infected D17 cells were selected for hygromycin resistance. Each hygromycin-resistant colony was analyzed under a fluorescence microscope.

^bThe rate of deletion of JZ442+3′ Hyg was 62%, whereas the rate mutation of JZ442 was 1% (24).

^cThe titer of viruses released from JZ442+3′Hyg was (0.86 × 10⁵) ± (0.38 × 10⁵) (24).