RNAi inhibition of Sbds expression. (A) Schematic of FCYsi lentiviral vector showing long terminal repeats (LTRs), U6 promoter-short hairpin RNA (shRNA) cassette, and cytomegalovirus (CMV)–YFP cassette. The sequences of the 3 Sbds-specific and the scramble shRNAs are shown in the lower panel. (B) Representative immunoblot of Sbds in parental BaF3 cells (1) and BaF3 cells transduced with FCYsi.empty (2) or Sbds RNAi A (3) vectors. β-Actin loading control is shown in the lower panel. (C) Quantification of Sbds protein levels; Sbds protein abundance in BaF3 cells transduced with FCYsi.empty was assigned a value of 100% (n = 4-6). (D) Sbds mRNA expression relative to β-actin mRNA in BaF3 cells was measured by real-time RT-PCR (n = 2). (E) Murine HPCs were transduced with scramble RNAi or Sbds RNAi A; YFP⁺ cells were sorted from cultures 72 hours after transduction and were cultured for 7 days. Shown is a representative immunoblot for Sbds and β-actin. *P ≤ .05, ***P ≤ .005, compared with control cells. All data represent the mean (± SD).