Fig. 4. Dome1 is essential for optimal tick metamorphosis.

(A) Host blood meal acquisition in Dome1-knockdown ticks. Number of fed ticks (left panel) and tick engorgement weights (right panel) are shown. (B) Intermolt ticks. Compared with controls, Dome1-knockdown post-fed (PF) ticks displayed lower weights (upper panels) and different body colors with exposed exuviae or even death (lower panels, arrowheads). (C) Impairment of molting success in Dome1-knockdown nymphal ticks, as assessed by the percentage of molted ticks. (D) Dome1 silencing in fed larvae impairs development and molting. The control intermolt ticks (left panels) at 20 days post-fed (PF) reveal newly formed legs (arrowheads) which were absent or malformed in Dome1-knockdown groups (right panels, arrows). The percentage of molted ticks is shown in the rightmost panel. (E and F) Compared with controls (E), transstadial Dome1-knockdown ticks (F) showed deformities (arrows), including in hypostome (H) and palps (P), uneven legs with unequal lengths, stunted legs without coxa, and darker abdomens with incomprehensible gut diverticula. (G) Dome1 is essential for fecundity and larval development. The data represent an experiment where 80 adult ticks were microinjected with dsDome1 or dsGFP (control) RNA and allowed to engorge on groups of rabbits. Dome1 deficiency resulted in abnormal egg and larval development (top right panels), compared with the controls (top left panels). Dome1 knockdown was sustained in the mature eggs, which were analyzed for Dome1 (bottom left panels) or Dome5 (bottom right panels) protein levels by immunoblot. See additional results for hatched larvae in fig. S11. Results are representative of two to five independent experiments where quantitative data are shown as individual data points; error bars show the means ± SDs (n = 6 to 50). Black or white bar: 100 μm; red bar: 50 μm. *P < 0.05, determined using two-tailed Mann-Whitney U test; n.s., not significant.