Figure 6.

NKX2-5 Represses Cardiac Expression of Fast Troponin Isoforms

(A) ChIP-seq trace at the repressed Lsp1 locus for the two experiments carried out (s1 and s4). Black bars indicate regions found enriched for NKX2-5.

(B) In situ hybridization on sections of E14.5 control and hypomorph hearts, using probes for Tnni2, Tnnt3, and Lsp1. Note the upregulation of Tnni2 and Tnnt3 signals in the hypomorph atria (black arrows). See also Figure S5A.

(C) Tnni2-Tnnt3 enhancer (Tnni2-Tnnt3-enh) activity in control and NKX2-5-deficient HL-1 cells is shown.

(D) Co-transfection of Tnni2-Tnnt3-enh with an increasing quantity of Nkx2-5-expressing vector shows a decrease of reporter activity. Tnni2-Tnnt3-enh-mut reporter vector is unaffected by Nkx2-5 overexpression in HL-1 cells. Only significant changes are indicated. ^∗p < 0.05 according to a two-tailed Student’s t test.