Lmo2 is a critical regulator of ALM development. (A-F) Whole-mount embryos; posterior views; dorsal, top; numbers of embryos represented in gray. (A) Although staining is generally weak in these embryos, hhex expression initiated as normal, appeared reduced at 6s/7s (arrows) and was lost by 10s. (B) Runx1 was at first dependent on Scl, initiating only weakly in the ALM of morphants at 10s (arrowhead). Pu.1 expression in the ALM of morphant embryos was substantially reduced (C), while scl, fli1, and gata2 expression was unaffected (D-F). (G) Data from in situ analyses are summarized schematically as previously described for Figure 3.