Fig. 2 S1

Exclusive endocardial expression of the Notch reporter Tg(TP1:VenusPEST)^s940 and cardiac cushions forming normally on overexpression of krit1 and ccm2.

(A–C) (A) Maximum projections of confocal z-stacks of 48 hpf heat-shocked wild-type (WT) embryo, (B) heat-shock-induced (hs) krit1 overexpressing embryo, and (C) hs-induced ccm2 overexpressing embryo. Myocardial cells and endocardial cushions are stained for Alcam (Magenta). Myocardial cells do not express the destabilized Notch reporter Tg(TP1:VenusPEST)^s940 (yellow), which is expressed within endocardium and endocardial cushions. (A'–C') Shown are projections of 3 confocal z-stack planes (1 μm each) of the same hearts as shown in (A–C). (A''–C”') Single confocal z-section images of the atrioventricular canal (AVC) region highlighted with a white square in the panels D-F. (A'''–C''') Inverted images of Notch reporter shown in A''-C'' (asterisks mark endocardial cushion cells). Note dowregulation of Notch activity on Krit1 and Ccm2 overexpression (B, C, B'–C'''). The morphology of endocardial cushions remains unaltered on krit1 and ccm2 overexpression at this stage (B''–C''). A: atrium, V: ventricle, arrowheads point at the AVC. Scale bars are 50 µm in A-F and 10 µm in D'-F''.