Fig. 5.

nkx2.5 is important for ventricle-specific vmhc gene expression. A: Shown are potential transcriptional factor-binding sites in distal and proximal elements, as predicted by bioinformatic analysis. Yellow diamonds represent the Nkx-binding sites (NKE); red bars represent the first two non-coding exons. B: Schematic summary of results from transient assays using the Tol2 transposon system. Deletion of the two NKE sites in the distal element (∼20 bp) or in the proximal element (∼15 bp) resulted in loss of ventricular specificity. No., number of injected embryos that survived to 4 dpf; Somite ratio/Heart ratio, number of fish with tissue-restricted GFP-positive cells over total number of fish that survived to 4 dpf; Ventricle No. or Atrium No., number of fish with GFP-positive cells in the ventricle or atrium. A fish with GFP-positive cells in both chambers was counted in both categories. V:A, ratio of GFP-positive cells in the ventricle over that in the atrium.