Figure 5

Bone marrow from Gata1^low mice express a discordant ribosomal signature and contain megakaryocytes with poorly developed endoplasmic reticulum and reduced numbers of polysomes. Summary of the fold-change with respect to wild type in the expression of genes for the large (top) and small (bottom) subunit of the ribosomes in bone marrow (a) and spleen (b) from Gata1^low mice. Results are expressed as log fold increase. Value statistically different (P<0.05) from those observed in wild-type mice are indicated by *. (c) Transmission electron microscopy of representative megakaryocytes from wild-type (WT) and Gata1^low littermates. Megakaryocytes were recognized by their distinctive morphology shown in the low magnification presented in the top panels. Details of the perinuclear area of the cells (indicated by the red square) showing the poorly developed rough endoplasmic reticulum with reduced numbers of polysomes (indicated by the yellow circles) are shown in the photographs obtained at greater magnification in the bottom panels. To be noted that the Gata1^low megakaryocyte is smaller and less mature than the wild-type one. Similar results were obtained by analyzing at least five separate megakaryocytes from three mice per group.