Figure 5.

Five base pair insertions between DCE subelements severely disrupt β-globin transcription in vitro. (A) Schematic diagram showing the design of the spacing mutants. βLONG is the wild-type β-globin promoter. The three subelements are as indicated using a black patch to indicate their orientation relative to each other. The arrows indicate the position of the 5-bp insertion. This position is also indicated in the name of each template (i.e., the 5 + 9 mutant has a 5-bp insertion starting at position + 9 of the wild type promoter). (B) In vitro transcriptional analysis of the spacing mutants. Wild-type and mutant promoter templates were incubated with a MEL nuclear extract. The resulting RNA product was detected by primer extension analysis, was run on an 8% sequencing gel, and was autoradiographed.