Sox6 is highly expressed and has cell-autonomous roles in erythroid cells. (A) Sox6 RNA in situ hybridization of a wild-type E15.5 fetus midsagittal section. The RNA signal is seen in red and cell nuclei blue. Tel indicates telencephalon; n, nasal cartilage; cc, chondrocranium; st, sternum; ve, vertebrae; and il, ilium. (B) Northern blots of RNA from mouse tissues, hybridized with Sox D probes. Staining of 28S RNA is shown as loading control. (C) Sox6 expression in E12.5 fetal liver cells. Three subpopulations, A to C, were sorted from wild-type tissue by CD71/TER119 FACS. Semiquantitative RT-PCR was performed for Sox6 and Hprt, the latter serving as loading control. (D) Immunofluorescence of cytospins from control and Sox6^–/– P7 bone marrow cells incubated with Sox6 antibodies (red signal) and FITC-labeled TER119, c-kit, or Mac-1 antibodies (green signal). Cell nuclei are blue. (E) Blood smears of E15.5 control and Sox6^fl+/fl+ErGFPCre mutant littermates. (F) CD71/TER119 FACS profiles of E18.5 fetal liver and P14 bone marrow in control and Sox6^fl+/fl+ErGFPCre littermates. (G) CD71/TO FACS profiles of blood from E18.5 and P14 control and Sox6^fl+/fl+ErGFPCre littermates.