Scanning electron micrographs of p45 NF-E2^+/+ (a), p45 NF-E2^+/− (b), and p45 NF-E2^−/− (c) cultured megakaryocytes, showing extension of proplatelets from within normal cells and the surface appearance of the mutant cells, which are appreciably larger in size but do not develop proplatelets. Note the long filamentous processes separating individual platelet-size particles.