Fig. 1.

MK morphology in the spleens of untreated and TPO-treated WT and Gata1^low littermates. Representative semithin sections from the spleen of untreated a,c) and TPO-treated b,d) WT a,b) and Gata1^low c,d) mice. Representative megakaryocytes are indicated by arrows. Only one MK is present in the semithin section from WT spleen a). By contrast, the semithin section of TPO-treated WT spleen b) shows nine MKs, six light (whole arrows) and three heavy electron dense (arrowheads). The sections from the spleen of untreated and TPO-treated Gata1^low mice are similar c,d). Original magnification: × 40.