Figure 11.

TGFβ inhibits the epitope unmasking and nuclear translocation of cyclin D3 induced by TSH. Quiescent 4-day-old dog thyrocytes were stimulated for 20 h with TSH (1 mU/ml) (T) with or without TGFβ (2 ng/ml) (β) or remained in control (C) condition. Cells were then processed for cyclin D3 immunofluorescent staining using the DCS-22 or DCS-28 monoclonal antibodies. For cyclin D3 detection using DCS-22, an epitope unmasking treatment by a mild trypsin digestion of fixed cells was applied (unmasked) or not. (A) Labeled cells were photographed using a 50× immersion lens. (B) Distribution of nuclear cyclin D3 immunofluorescence intensities within the cell population as measured by photometry. Cyclin D3 was detected using DCS-22 without the application of the trypsin unmasking treatment. Values of nuclear immunofluorescences exceeding the weak to moderate ones recorded in 90% of unstimulated control cells were scored positive and are shown as filled bars. Average values of immunofluorescence intensity are indicated for each treatment.