Fig. 5.

Silencing of Pax8 affects Cadherin-16 expression both in vitro and in vivo. A, FRTL-5 cells were transfected with a PAX8 siRNA that specifically targets the rat Pax8 coding region. Pax8 and Cadherin-16 (CDH16) expression levels were measured on total RNA by qRT-PCR 24 and 48 h after siRNA transfection. The values are means ± sd of three independent experiments in duplicate, normalized by the expression of β-actin, and expressed as fold change with respect to the untransfected FRTL-5 cells, whose value was set at 1.0. Statistical analysis uses t test (P < 0.01). B, In situ hybridization using DIG-labeled Cadherin-16 riboprobe was performed on sagittal sections of E10.5 wild-type (WT) and Pax8^−/− (KO) embryos. A strong Cadherin-16 expression is observed in the wild-type developing thyroid, whereas thyroid precursor cells lack the expression of Cadherin-16 in the Pax8^−/− thyroid bud. In parallel, an immunofluorescence analysis was performed on sagittal sections of E10.5 Pax8^−/− embryos, with the anti-E-cadherin antibody, to confirm the presence of epithelial cells in the forming thyroid primordium.