Silencing of Wdr26 results in reduced nuclear opening rate in differentiating erythroblasts. (A) Immunofluorescence assays with Lamin B antibody showed reduced nuclear opening ratio in Wdr26-knockdown primary mouse erythroblasts in comparison with the control shRNA cells at 48 hours after erythropoietin treatment. Error bars represent SEM from 3 replicates. At least 50 cells were quantified for each shRNA. *P < .05, **P < .01. (B) Representative images of panel A. Scale bars, 5 μm. (C) Immunofluorescence analyses of Lamin B and H2B in control and Wdr26-silencing primary mouse erythroblasts at 48 hours after erythropoietin treatment. Scale bars, 5 μm. (D-G) Treatment with farnesyltransferase inhibitors (1 μM Tipifarnib or L744832) rescued the defects of nuclear condensation and nuclear opening in Wdr26-silencing erythroblasts. Shown are representative images of (D) DAPI-stained nuclei and (G) Lamin B immunofluorescence, as well as the quantification of (E) nuclear size and (F) nuclear opening events. Error bars represent SEM from 3 replicates. At least 50 cells were quantified for each treatment condition. **P < .01. Scale bars, 5 μm. (H) Farnesyltransferase inhibitors partially rescued the enucleation defect in Wdr26-silencing erythroblasts. *P < .05. (I) The proposed role of Wdr26 in regulating nuclear protein degradation and nuclear condensation during vertebrate erythropoiesis. ProE, proerythroblast.