Figure 8

Loss of MBNL1 stimulates endocardial cell invasion in OFT explants. Stage 14 OFT explants were transfected with or without MBNL1 siRNA. Representative images of mock- (A, A’) or MBNL1 siRNA-treated (B, B’) OFT explants were taken in the focal plane of the surface of the gel (A, B) to show activated endocardial cells and within the gel (A’, B’) to show invaded mesenchymal cells. Filled arrowheads indicate cells in the focal plane, whereas open arrowheads indicate the same cells out of focus in a different plane. (C) The numbers of activated and invaded cells were counted at 38 hrs. The mean number of cells per explant + the standard error of the mean is shown. Transfection with either of two MBNL1 siRNAs, but not a control siRNA, enhanced invasion in OFT explants. Activation was not significantly affected. An asterisk indicates a significant difference from mock-transfected explants (P ≤ 0.05).