HSPCs accumulate in Sin3B^CKOmice. (A) Expression pattern of Sin3B obtained from Gene Expression Commons using the Transcriptome Analysis Identifies Regulators of Hematopoietic Stem and Progenitor Cells Model. Numbers indicate the percentage “activity level” based on the dynamic range of microarray probes as described in Seita et al.²¹  (B) Polymerase chain reaction analysis of genomic DNA isolated from bone marrow mononuclear cells of indicated genotypes. (C) Quantification of the number of cells present in the indicated organs of control and Sin3B^CKO animals; n = 6. (D) Frequency of indicated cell populations in the peripheral blood of animals; n = 6. (E) Frequency of indicated cell populations in the spleen of animals; n = 6. (F) Representative FACS plot for various HSPC populations. Mean frequency of indicated cell populations are indicated; n = 6. P < .05 for lin^- sca1⁺ ckit⁺ (LSK), ST-HSC, and LT-HSC. (G) Quantification of the cell number of indicated HSPC populations; n = 6. Data are represented as mean ± standard error of the mean (SEM). *P < .05; **P < .01. BM, bone marrow; CLP, common lymphoid progenitor; CMP, common myeloid progenitor; GMP, granulocyte-macrophage progenitor; LP, lineage positive; MEP, megakaryocyte-erythroid progenitor; MP, myeloerythoid progenitor; MPP, multipotent progenitor.