Northern blot analysis displays defective pre-rRNA processing in CD34⁺ cells from patients with DBA who have mutations in RPS19. The figure shows a representative Northern blot using total RNA isolated from CD34⁺ cells and prepared for Northern blot analysis as described in Figure 2. Pre-rRNAs were hybridized with oligonucleotide γ (Figure 1) to examine the ratio of 21S to 18SE pre-rRNA.