Mutational analysis of SCL/Tal-1 and GATA motifs in the

Flk-1 minimal enhancer in transgenic mouse embryos. Mutations were introduced into the indicated transcription factor sites shown in Figure 2, as presented in Table 1. The LacZ reporter gene is expressed under the control of the 939-bpFlk-1 promoter and mutants of the 430-bp minimal enhancer. Different representative transgenic embryos are shown after LacZ staining. (A,B) Mutation of the SCL/Tal-1 site (bp 232). (C,D) Mutation of the SCL/Tal-1 site (bp 358). (E) Mutation of the GATA site (bp 43). (F,G) Mutation of the GATA site (bp 72). (H) Mutation of the GATA site (bp 264).