Fig. 5: Slit2 and Ntn1 are Tbx5-sensitive genes in the IVS.
From: A disrupted compartment boundary underlies abnormal cardiac patterning and congenital heart defects
a, At E13.5, we microdissected the RV, LV and IVS + AVCo regions in Tbx5CreERT2/+ controls and Tbx5CreERT/flox mutants (Tbx5CreERT2/flox;Mef2cAHF-DreERT2;ROSA26Ai6/Ai66) with the labeled Tbx5+/Mef2cAHF+ lineage (tdTomato+) and Tbx5+ lineage (ZsGreen+) cells, after a single dose of tamoxifen at E6.5. b, UMAP visualization of IVS + AVCo by cell type clusters and Tbx5 genotype (inset) (controls, n = 4; Tbx5 mutants, n = 2). WBCs, white blood cells; RBCs, red blood cells. c,d, tdTomato+ (c) and ZsGreen+ (d) cells are enriched among CMs. e,f, UMAP shows a Tnnt2+ CM subset by Tbx5 genotype (e) or Louvain clusters (f). g, Feature plots show that AVCo region genes (Rspo3, Bmp2, Robo1, Unc5b) are enriched among control-enriched cluster 5, suggesting downregulation of these genes in Tbx5 mutants. Trabecular genes (Cited1, Nppa, Slit2, Ntn1) were enriched in the Tbx5 mutant-enriched cluster 10. h, Dot plots of selected genes that are upregulated in cluster 10 (C10) or in cluster 5 (C5). The significance of adjusted P < 0.05 was determined by two-sided Wilcoxon rank sum. i–n, Fluorescence in situ hybridization of trabecular genes Nppa, Slit2 and Ntn1 in Tbx5CreERT2/+ controls or Tbx5CreERT2/flox mutants at E14.5. i,i(i),k,k(i), Nppa and Slit2 are normally expressed in the ventricular trabecular layer and excluded from the core of the IVS. j,j(i),l,l(i), In a Tbx5CreERT2/flox mutant with an intact IVS, Nppa and Slit2 are misexpressed in the IVS (asterisks). m,m(i), Ntn1 is normally expressed in the trabecular layer and in a gradient across the IVS from left to right, demarcated by a yellow dashed line. n,n(i), In a Tbx5CreERT2/flox mutant with an intact IVS, Ntn1 is expanded across the IVS, flattening its gradient. All scale bars, 200 μm.
