Fig. 3: Cell ablation of Tbx5+/Mef2cAHF+ progenitors causes RV hypoplasia, IVS disorganization and lineage mixing.
From: A disrupted compartment boundary underlies abnormal cardiac patterning and congenital heart defects
a–j, Misexpression of diphtheria toxin (DTA) in Tbx5+/Mef2cAHF+ progenitors in Tbx5CreERT2/+;Mef2cAHF-DreERT2;ROSA26Ai66/+;Hip11intersectional-DTA/+ embryos (DTA), compared with Tbx5CreERT2/+;Mef2cAHF-DreERT2;ROSA26Ai66/+;Hip11+/+ (control), resulted in RV hypoplasia (arrows) at E9.5 (a and b; scale bars, 500 μm) and E12.5 (c–j; scale bars, 250 μm (c–g, i), 150 μm (h), 100 μm (j)), along with disorganization and non-compaction of the IVS (asterisk) (g–j). k–n(i), At E10.5, mixing of the Tbx5+ lineage (white arrows in n(i) show ectopic Tbx5+ lineage ZsGreen cell in the right heart) was observed by lightsheet microscopy in Tbx5CreERT2/+;Mef2cAHF-DreERT2;ROSA26Ai6/Ai66b;Hip11intersectional-DTA/+ embryos (DTA) (n = 2) compared with Tbx5CreERT2/+;Mef2cAHF-DreERT2;ROSA26Ai6/Ai66b;Hip11+/+ embryos (control) (n = 3). Scale bars, 100 μm (l–n(i)). k,m, Cartoon depictions of the experiment. o, Distribution of the Tbx5+ lineage by ventricular chamber shows that the Tbx5+ lineage is increased in the RV of DTA mutants (***P = 0.000513 by two-sided t-test) compared with controls. Cells of the RV and LV were evaluated in five optical slices at different anterior–posterior planes per embryonic heart sample of three controls and two mutants. Mean and standard deviation are shown. p–r, Linear profiles quantified fluorescence intensity across the heart at the right or left (R/L) positions. Tbx5+ lineage cells expanded rightward into the RV (depicted in r by the hashed area; the dashed green box in q shows significant difference between traces, indicative of a rightward expansion (green arrow)), consistent with a compartment boundary disruption. Linear profiles at five apical–basal planes per optical slice, for five optical slices at different anterior–posterior planes per embryonic heart sample of three controls and two DTA mutants were assessed, as depicted in p. Statistical significance (P < 0.05) between linear profiles of control and DTA mutants was determined by Welch’s two-sided t-test at each position along the right–left axis. Mean and standard error of the mean are shown. Precise Pvalues can be found in the source data.
