Diagrams and expression of constructs containing the μLCR and ^Aγ-globin gene with promoter truncations. (A) Is for constructs containing the normal ^Aγ-globin promoter sequence, while (B) is for constructs containing the indicated G → A point mutation at position −117 of the^Aγ-globin promoter associated with hereditary persistence of fetal hemoglobin. In the diagrams to the left, the μLCR is indicated by the thick hatched bar, while the ^Ag-globin gene is indicated by the thin filled bar. Exons are indicated by the filled boxes, the site of transcription initiation (cap site) by the arrow, while the positions of the individual promoter truncations are relative to the cap site. To the right of each panel is shown the number of transfected MEL585 pools included in the analysis, along with the mean, standard deviation (for data sets containing more than three pools), and range of expression for each construct. Expression was determined by quantitative RNase protection and is expressed as a percentage of the level of endogenous murine -globin mRNA on a per copy basis.