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. 2004 Jul 1;18(13):1553–1564. doi: 10.1101/gad.299904

Figure 6.

Figure 6.

The Fmn locus encodes a regulatory region sufficient to activate Gremlin transcription in the limb bud mesenchyme. (A) Construct A was generated by in frame insertion of a LacZ gene 30 bases downstream from the Gremlin ATG (exon 2) into BAC #113H17. This BAC encodes Fmn exons 19–24, the intergenic region, entire Gremlin gene and extends ∼150 kb upstream of Gremlin exon 1. Note that Gremlin (bold arrow) is transcribed in reverse orientation to Formin (arrow). (B) Construct B was generated by deleting the genomic region delimited by exons 19–23 from construct A. (C) Construct C was generated by replacing Fmn exon 23 and all downstream sequences with the β-lac reporter gene in BAC #113H17. Note that the β-lac reporter gene inserted in construct C is transcribed like Gremlin, that is, in reverse orientation (bold arrow) to Formin; exons are numbered as in Figure 2A. For all constructs, the LacZ distribution is shown in founder embryos around gestational day 10.5. Left panels show whole embryo views and right panels show forelimb buds. Note that different embryos are shown in the left and right panels. Black arrowheads point to the LacZ expression domains in the limb bud. Open arrowheads indicate the lack of LacZ expression in the limb bud of an embryo transgenic for construct B.