Effects of MBNL1 knockdown on cell invasion remain dependent on TGFβ3 after induction of EMT. Stage 14 AVC explants were transfected with or without MBNL1 siRNA. Anti-TGFβ antibodies or medium alone were added at 18 hours. Representative images of explants that were mock-transfected plus medium alone (A, A’), MBNL1 siRNA-transfected plus medium alone (B, B’), and MBNL1 siRNA-transfected plus anti-TGFβ3 antibody (C, C’) were taken in the focal plane of the surface of the gel (A, B, C) and within the gel (A’, B’, C’) 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. (D) The number of invaded cells was counted at 38 hrs. The mean number of invaded cells per explant + the standard error of the mean is shown. Inhibition of TGFβ signaling has little effect on the basal level of cell invasion in mock-transfected explants. Inhibition with a pan-TGFβ or TGFβ3-specific antibody blocked the enhancement of cell invasion by MBNL1 knockdown, whereas inhibition with a TGFβ2-specific antibody did not. An asterisk indicates a significant difference from mock-transfected explants without antibody treatment (P ≤ 0.05).
LeMasters et al. BMC Developmental Biology 2012 12:22 doi:10.1186/1471-213X-12-22