Effect of ALS genotype on the expression of the ALS gene. (Left) Total RNA was isolated from the liver and kidney of 10-week-old mice. Aliquots (15 μg) from wild-type (+/+, lanes 1 and 2), heterozygous (+/−, lanes 3 and 4), and null (−/−, lanes 5 and 6) ALS mice were analyzed by Northern blotting using the coding ALS probe that detects a unique mRNA of ≈2.2 kb. The signal obtained with the 18S riboprobe is shown for both tissues. (Right) For each tissue, means ± SE of ALS hybridization signals are shown (six animals per genotype). Means with different letters differ at P < 0.05 using GLM followed by Fisher's protected least significant differences analysis.