Fig. 7. Evolutionary conservation of MEOX1 enhancer and regulatory mechanism across vertebrates.

a Genomic alignment of chick MEOX1 locus, ~10 kb. Exons and introns are represented by blue boxes and lines. Clustered green vertical lines indicate sequence identity between different species. The height of bars indicates extent of conservation in different species: turkey, zebra finch, American alligator, Chinese softshell turtle, Lizard, Human, Mouse, Zebrafish, Nile tilapia, Stickleback, Medaka, Fugu, Lamprey and Xenopus tropicalis, as indicated on the left of each row. Grey shading indicates the location of the MEOX1 Enh. b Expression of the conserved human MEOX1 Enh reporter in presomitic mesoderm, somites and lateral plate mesoderm in a HH9 chick embryo (n = 6/6). c Mutation of FOXO1 and ZIC3 binding sites in the human MEOX1 Enh Citrine reporter led to loss of expression (n = 4/4). d Chick MEOX1 Enh reporter injected into 1 cell of a Xenopus laevis 2-cell embryo shows Citrine expression in paraxial mesoderm (St14, white arrowheads (n = 6/6)) and in early somites and elongated myofibres (St25 (n = 6/6), St33 (n = 6/6), St42 (n = 6/6), white arrowheads). A-P anterior–posterior. Scale bars for b, c = 500 μm, d scale bar = 250 μm.