D: Validation of the involvement of Group X target genes Lrsam1, Ap2a1, Mettl22, and Hal in zebrafish hematopoiesis by MO-mediated knockdown. Whole-mount in situ hybridization of Runx1 and c-Myb expression is shown at 26 hpf and 30hpf, respectively. Prdm16 knockdown serves as a positive control. Note that nonspecific staining for Runx1 and c-Myb was largely unaffected by targeted MO knockdown, whereas HSC markers Runx1 and c-Myb staining were notably reduced in discrete cells in the ventral region of the dorsal aorta (arrows). Scale bar = 100 µm. 