Globin gene expression in Hb Lepore‐BAC transgenic mice

Summary We generated five lines of transgenic mice carrying 1–3 copies of the Hb Lepore δβ fusion gene, in the context of a Bacterial Artificial Chromosome containing the whole human β globin gene cluster. Normal developmental regulation of human genes occurred at levels approximating to those of endogenous genes. δβ transgene expression became detectable during fetal life and rose to a mean level of 13·0% in adults, similar to that of humans. Low levels of human γ chains were detectable as F cells in adult mice, but numbers did not increase after treatment with drugs that raise F cells in human subjects, even on a thalassaemic background.