Table 1.

Features of Nrl^–/– Photoreceptors Compared with Those of WT Mouse Rods and Cones

Feature	Nrl–/– Photoreceptors	WT Cones	WT Rods	Figure (Current Study)
Ultrastructure
OS length (μm)	7.3 ± 1.3 (21)	13.4 ± 0.7*	23.6 ± 0.4*	Fig. 2
OS width (μm)	1.2 ± 0.3 (21)	1.2 ± 0.03*	1.4 ± 0.1*	Fig. 2
OS volume (μm3)	8.3	14	36
Open discs	up to 30	>15*	5-7*	Fig. 2
Mitochondrial length (μm)	0.94 ± 0.38 (50)	1.31 ± 0.7 (13)*	2.20 ± 0.7 (15)	Fig. 2
Histological
Chromatin clumping	Yes	Yes	No	Fig. 1
PNA-stained OS sheath	Yes	Yes	No	Fig. 3
Molecular
MUV	Yes	Yes	No	Figs. 3-5
Gtα2	Yes	Yes	No	Fig. 5
mCarr	Yes	Yes	No	Fig. 5
Arrestin	Yes†	Yes, low level‡	Yes
ERG a-wave
λmax (nm)	360	360	500	Fig. 6
tpeak (ms)	≈50	unknown	140§	Fig. 7

The first column gives a list of the features on which Nrl^–/– photoreceptors, WT rods, and WT cones are compared. Entries summarize data from this investigation or from previously published work. Error terms are standard deviations; numbers following in parentheses give sample size.

^*Carter-Dawson and LaVail.²⁸

^†Mears et al.⁵

^‡Craft and Zhu, personal communication, 2004.

^§Hetling and Pepperberg,⁴¹ who used the paired-flash method to extract rod responses from WT mice, as was used in the present study in Nrl^–/– mice.