FIG. 1.

Dfr/Vvl is localized to the nuclei of fat body, digestive system, and barrier epithelia in uninfected larvae. Shown are immunostaining of Dfr/Vvl (red) in dissected tissues from third instar larvae and staining of nuclei with DAPI (4′,6-diamidino-2-phenylindole) (blue). Strong nuclear Dfr/Vvl staining was evident in the fat body (fb) (A and A′), salivary glands (sg) (B and B′), and trachea (tr) (C and C′). In the malpighian tubules (malp), different regions reproducibly conferred either equal distributions between the nuclei and cytoplasm (D and D′) or predominantly nuclear distribution (E and E′). In the digestive system, Dfr/Vvl staining was intense in the proventriculus (pv) (F, G, and G′), in gastric ceca (gc) (F), and in the hindgut (hg) (H and H′). In the midgut (mg), Dfr/Vvl staining was weak and diffuse (F and H). Also shown are differential interference contrast micrograph of the larval cuticle (cut) and epidermis (epi), with two ventral denticle belts (db) visible (J) and fluorescence micrographs of the same specimen showing nuclear localization of Dfr/Vvl (J′) and DAPI (J") in epidermal cells. Tissues/organs were named according to M. Demerec (45).