Effect of gene targeting on Nrf-2 transcript size. Northern blot analysis of total RNA from bone marrow (Nrf-2 (+/+), 13.0 μg RNA; Nrf-2 (-/-), 9.6 μg RNA). The blot was probed with full-length Nrf-2 cDNA (top) or β-actin cDNA as a control (bottom).