Expression of mDYRK-3 at high levels in primary progenitor cells of erythroid lineage.
(A) To determine the extent to which mDYRK-3 expression might be limited to erythroid progenitor cells, marrow cells were cultured under conditions selective for the outgrowth of erythroid, granulocytic and monocytic (g/m), or megakaryocytic progenitor cells.31 At time points determined in advance to correspond to maximum enrichment of late progenitor cells in each series, RNA was prepared and levels of mDYRK-3 (and hgprt) transcripts were assayed (upper panel). (For erythroid, granulocytic and monocytic, and megakaryocytic lineages, this corresponded to days 3, 7, and 4 of culture, respectively). Illustrated in center and lower panels are profiles of pf4 transcript expression in Tpo/IL-3–expanded cultures (megakaryocytic cells), and of mac-1 transcript expression in IL-6/IL-3/SCF–expanded cultures (granulocytic and monocytic). For erythroid cells, profiles have been characterized previously.24 31 (B) The mDYRK3 transcript expression was also analyzed in staged and sectioned mouse embryos at days 11 through 16 by in situ hybridization to a33P-UTP–labeled mDYRK3-specific antisense RNA probe. The strong hybridization to fetal liver shown is representative of 4 independent sections and was maximal at days 12 through 15.
