Northern blot analysis of AML1-ETO expression in transgenic mice with or without tetracycline.

Double-positive mice from founder line #8 were generated by breeding heterozygous mice in which the females harbored a subcutaneous time-release tetracycline pellet that releases 0.7 mg tetracycline per day. F1 mice were weaned and continued to receive tetracycline (1 mg/mL) in their drinking water. Tetracycline was withdrawn from two 58-day-old mice, and the mice were maintained in the absence of tetracycline. Two other 58-day-old mice continued to receive tetracycline. Three weeks after tetracycline was removed or continued, the mice were killed and the bone marrow from the femurs was harvested. Total RNA from the marrow was isolated and 8.5 μg was loaded on each lane. The RNA was then transferred to a nylon membrane and hybridized sequentially with ETO and tTA probes. The ethidium bromide staining of the 28S ribosomal RNA is presented to show the loading of the RNA samples.