Figure 2. col Requirement for Lamellocyte Differentiation.

(A–C) 4′,6-diamidino-2-phenylindole (DAPI) staining of hemocytes from wt (A and B) and from col¹ (C) third instar larvae. (A) Uninfected larva; (B) and (C) infected larvae. Plasmatocytes (inset in [A]) are always present, whereas lamellocytes (inset in [B]) are detected in the hemolymph of wt (B) but not col¹ (C) larvae 48 h after infestation by L. boulardi. In col¹ mutants, the wasp eggs are not encapsulated (white arrows) and develop into larvae (bottom right organism in [C]).

(D–F) Lamellocytes expressing the P-lacZ marker l(3)06949 (Braun et al. 1997) surround the wasp eggs in wt larvae (D), are completely absent in infected col¹ mutant larvae (E), and differentiate in the absence of wasp infection following enforced Col expression in hematopoietic cells (srpD-Gal4/UAS-col larvae) (F). (G) srpD-Gal4/UAS-col pupa showing the presence of melanotic tumors.

Bars: 50 μm.