Whole-mount in situ hybridization analysis of hematopoietic markers in control- and arhgef3 MO-injected embryos. Expression analysis of the hematopoietic-specific markers scl, gata2, gata1, alas2, and hbbe3 in arhgef3 MO-injected embryos showed that all 5 genes were normally expressed at 24 hpf compared with control embryos. However, whereas in control embryos scl, gata1, alas2, and hbbe3 expression diminished in the ICM by 30 hpf and persisted only in its posterior region, arhgef3 MO-injected embryos exhibited a persistently strong expression of all 4 markers in the ICM (denoted by framed figures and black arrows). In situ hybridization for the late myelomonocytic markers at 22 hpf showed that there is no alteration in the expression of l-plastin or mpx in arhgef3 MO-injected embryos compared with the controls.