Ribosomal protein gene dysregulation in human MDS and summary of a mouse model. (A) Fold-change of mRNA for 8 patients with low-risk, non-5q− MDS compared with 11 healthy, age-matched control patients; each bar represents a different array probe for ribosomal protein genes that are differentially expressed. As described in the text, of 74 ribosomal protein genes represented on the array, 21 genes exhibited reduced mRNA levels and 1 gene exhibited increased mRNA levels (represented by a total of 34 probes). The figure shows all ribosomal protein gene probes that exhibit significant (< 0.01% false-discovery rate) differences; genes with multiple probes are indicated with an asterisk (*). (B) Diagram of the hematopoietic lineage and differences observed in BM-specific Rps6 mutant mice. Red arrows summarize alterations in Rps6 mutant animals on the basis of Figure 5A, C, and D, including a reduction in the size of the HSC population, a concomitant increase in the size of most downstream progenitor populations, and a block in erythroid maturation.