Fig. (4) HDAC2 nuclear overexpression attenuates differentiation of HFK cells. Primary cultures of HKF cells were transiently transfected with the mammalian expression vector HDAC2-Flag under culture conditions maintaining the undifferentiated state (KSFM no serum). Standard indirect immunofluorescence against the Flag epitope and Keratin-10 was then performed after 3 days in HFK differentiation media with 10% nFBS. DAPI was used to identify normal and fragmented nuclei. All three individual images of cell pairings are within the same field of view to normalize relative fluorescence.