Use of the β-globin promoter confines FGF2 expression to the bone marrow.

<p>(a) Schematic of the self-inactivating (SIN) lentiviral vector for expression of the modified human FGF2 and GFP control. Δ indicates the SIN design with partially deleted U3 of the 3′ long terminal repeat. cPPT, central polypurine tract; Wpre, posttranscriptional regulatory element; RRE, rev-responsive element; SFFV, spleen focus-forming virus U3 promoter; ψ, packaging signal; β-globin: the human β-globin promoter from 5′ translated region (1.6 kb). (b) ELISA analysis of FGF2 in BM erythroid (Ter119⁺) and non-erythroid (Ter119⁻) cells demonstrates the specificity of the β-globin promoter. (<b>c</b>) The use of β-globin promoter leads to confined expression of FGF2 to the marrow. Serum levels and FGF2 expression were determined in marrow cells from mice that had received Sca-1⁺ cells transduced with Lenti β-globin-FGF2 or Lenti SFFV-FGF2 (n = 5 mice/group). The relative ratio of FGF2 levels in serum to the marrow is presented.