Fig. 3. Design of transgenic constructs. (A) Promoters and intronic regions [with associated DHS clusters (arrowheads)] in the Ikaros locus used in transgenic studies. (B) Cartoon diagram of transgenic constructs. 400(p)-GFP consists of: 442 bp of the conserved region upstream of exon 2 (p) with the splice acceptor site, 5′ end of exon 2 and the EGFP gene. 600-GFP consists of: 632 bp of the entire conserved region upstream of exon 2 with the splice acceptor site, the 5′ end of exon 2 and the EGFP gene. A-GFP-B is a DHS-C2 and -C3 genomic fragment with a EGFP gene inserted into a PstI site within exon 1a. A-B-GFP is a DHS-C2 and -C3 genomic fragment with a EGFP gene inserted into the XbaI site within exon 1b. A-p-GFP consists of a BamHI–EcoRI fragment containing the untranslated exon 1a and the neighboring DHS-C2 cluster, ligated to 400(p)-GFP. B-p-GFP consists of an EcoRI fragment containing exon 1b and the upstream DHS-C3 cluster, ligated to 400(p)-GFP. B-p-GFP-C contains the additional downstream EcoRI fragment, which contains the intronic DHS-C6 cluster flanked by loxP sites.