TABLE 2

Experiment	Cell strain	UDSa	Range of relative rateb (%)
I	XP43TO/Mori	16.0  0.3/18.1  0.3 c	85–92
	XP82TO/Mori	15.4  0.4/20.4  0.4c	75–80
	XP89TO/Mori	6.8  0.2/24.0  0.5c	27–30
	XP24KO/Mori	14.0  0.3/11.7  0.3c	114–125
	GM02415B/Mori	23.9  0.4/26.6  0.4c	87–93
II	XP82TO/Turu	26.6  0.3/22.0  0.3c	118–124
	GM02415B/Turu	30.4  0.4/27.7  0.4c	120–125
III	Turu/Mori	23.2  0.3/25.9  0.3c	87–92
	Sono/Mori	18.8  0.3/15.6  0.2c	110–113
IV	Goryo/Mori	11.6  0.2/11.8  0.3d	94–103
	Umi/Mori	8.3  0.2/11.2  0.3c	70–78
	Mura/Mori	12.5  0.3/17.6  0.2c	69–73
V	XP24KO/Morie	15.3  0.3/13.6  0.2c	109–116
VIf	Ops2 (XPA)/Mori	2.9  0.8/35.7  2.6c	5–11
	Ops3 (XPA)/Mori	2.2  0.4/26.8  1.7c	6–10
	Ops12 (XPA)/Mori	2.9  0.4/30.1  1.0c	8–11
	Ops24 (XPA)/Mori	4.5  0.5/24.5  1.2c	16–21
	Ops34 (XPA)/Mori	3.8  0.5/40.6  1.7c	8–11
	Ops35 (XPA)/Mori	1.4  0.3/28.8  1.1c	4–6

^a To measure UDS (unscheduled DNA synthesis), cells were irradiated with UV at a dose of 30 J per m², and then immediately labeled with [³H]thymidine (50 Ci per ml) for 2.5 h. Exposure time was 24 h. UDS is given in grains per nucleus. Data are mean  SEM of 300 determinations except for experiment VI (50 determinations).

^b Range of relative rate is the range of UDS values (grain-numbers) of cell strains tested compared with those of the normal control (mori or Turu) cells.

^c p < 0.001.

^d p > 0.1.

^e This experiment was performed at a dose of 10 J per m^2.

^f These experiments were control experiments using XPA cells. All cell strains were assigned to XPA by the Kumamoto laboratory. Ops2, Ops3, and Ops24 have homozygous G to C substitution at the 3' splice acceptor site in intron 3 of XPA gene (Itoh and Yamaizumi, unpublished data).