β1 tubulin expression in p45 NF-E2^−/−megakaryocytes does not by itself induce the formation of proplatelets.

Wild-type (right) or p45 NF-E2^−/− Lin⁻ cells (left) were infected with retroviruses encoding p45 NF-E2 or β1 tubulin or were not infected as indicated on the top. After 3 days of culture, immunofluorescence was performed using β1 tubulin-specific antiserum (bottom) or a monoclonal antibody reactive against all β tubulin isoforms (middle). Phase-contrast images of the same microscopic field are shown for each case.