Expression of globin mRNA in transgenic mice containing 5′HS1 and/or β-globin distal promoter constructs. (A) S1 nuclease analysis of fetal liver RNA of 15.5 day F0BGT22 transgenic mice showing that the range of expression from single-copy transgenes is 13% to 889% per copy and indicating that the distal promoter is important for reproducible expression levels. (B) S1 nuclease analysis of fetal liver RNA of 15.5 day F0BGT23 transgenic mice showing that the range of expression from single-copy transgenes is 33% to 384% per copy and indicating that 5′HS1 is important for reproducible expression levels. (C) S1 nuclease analysis of fetal liver RNA of 15.5 day F0 BGT33 transgenic mice showing that the range of expression from single-copy transgenes is 87% to 136% per copy and showing that both 5′HS1 and the distal promoter are required to obtain reproducible full expression levels. Hβ, human β-globin protected probe fragment; βmaj, mouse β major protected probe fragment; Ntg, nontransgenic; μD, one copy μD14 microlocus line; 3X, probe excess control. {/ANNT;4224n;;left;71808n}C {/ANNT;4224n;;0n;0n}A {/ANNT;4224n;;84480n;0n}B
