Highly conserved non-coding regions (HCNRs) located between Irx5 and Irx6 genes show enhancer activity in zebrafish and Xenopus.(A–D) Lateral views of 24-hpf zebrafish embryos showing distribution of enhanced green fluorescent protein (EGFP) promoted by different HCNRs. (E–H) Lateral views of late neurula Xenopus embryos showing EGFP mRNA localization. Inset in E shows a higher magnification of the embryo from a ventral view. The number in the lower righthand corner of each panel corresponds to the position of the human homologous region in chromosome 16 (NCBI build 33) as shown in Figure 1J. Illustrations show a schematic representation of the expression domains in which the HCNRs are active. (fb) Forebrain; (mb) midbrain; (hb) hindbrain; (ey) eye; (h) heart territory.
