Northern blot analysis of CD34⁻ BM cells reveals abnormal pre-rRNA processing in patients with DBA who have mutations in RPS19. Total RNA was isolated from CD34⁻ cells and prepared for Northern blot analysis as described in Figure 2. Panels are designated according to oligonucleotides used for hybridization. Patients with DBA who have mutations in RPS19 are designated DBA-7⁻ and DBA-8⁻, while patients with normal RPS19 are designated DBA-1⁺ to DBA-5⁺. Samples from DBA patients labeled DBA-7⁻ and DBA-8⁻ have a chromosome breakpoint mutation in RPS19 and a complete deletion of RPS19, respectively. Ratios listed in Table 1 are derived from phosphorimage analysis of signals for the RNA species listed. Not all samples listed in Table 1 are shown in here.