FIG. 4.

Nucleolin is present in the cytoplasms of differentiating erythroid cells. (A) Nucleated erythroid progenitors contain cytoplasmic nucleolin. Western blot analysis was performed on total (T), nuclear (N), and cytoplasmic (C) extracts prepared from MEL cells using nucleolin (Nuc) antibody. The blot was stripped and rehybridized with antibodies directed against nucleus- and cytoplasm-specific histone deacetylase-2 (HDAC-2) and β actin, respectively. Affinity-purified nucleolin was analyzed in parallel as a positive control. (B) Anucleate erythroid progenitors (reticulocytes) contain cytoplasmic nucleolin. Hemolysate prepared from FACS-sorted murine reticulocytes (Retic) was analyzed by Western transfer analysis using nucleolin antibody. Total, cytoplasmic, and nuclear extracts prepared from MEL cells were analyzed in parallel as positive controls, and recombinant αCP was run as a negative control (NC). The blot was stripped and rehybridized with HDAC-2 antibody to confirm the absence of contaminating nucleoplasm in the Retic sample.