Results of whole-mount in situ hybridization of c-mpl and c-mpl and scl morpholino injection. Shown are the results of whole-mount in situ hybridization with antisense c-mpl cRNA (A; high power, B) at the embryo 3 dpf. c-mpl⁺ cells are detected in the same location as CD41⁺ and GFP⁺ cells detected in previous studies. Injection of a zebrafish c-mpl antisense morpholino (MOc) reduced the number of GFP⁺ cells 3 and 5 dpf. c-mpl morphants have some residual GFP⁺ cells. Injection of an inverted morpholino (MOinv) did not decrease the number of circulating GFP⁺ cells. Injection of 2 scl morpholinos (MOs) also reduced the number of GFP⁺ cells in the morphants at 4 dpf, in addition to causing tail deformation. For comparison, uninjected siblings of the same developmental stages are posted in the right corner of each picture.