Ae. aegypti salivary gland markers. Expression of crebA marks the developing salivary glands (arrowheads) in Ae. aegypti. (A) shows a low magnification view of the head and anterior segments of a 68-h embryo. (B) A higher magnification view of the salivary glands of this embryo is shown. (C) shows a negative sense control probe stain. (D-G) Expression of (D) sec63, (E) srp54, (F) betaCop and (G) a number of additional marker genes also labels the developing Ae. aegypti salivary glands. (C-F) display regions comparable to that which is shown in (B). (G) High magnification views of only the salivary glands are shown at right. Although expression of all the genes listed in (G) was detected in the developing embryonic salivary gland (signified by ‘Yes’ at left), Drosophila VNE placode-like expression patterns of these genes were not observed at the relevant stages of embryonic development in Ae. aegypti (signified by ‘No’ at left; NA indicates that gene expression was not assayed at the onset of salivary gland development). In all panels, marker gene expression is shown in dorsal views of Ae. aegypti salivary glands that are oriented anterior-left (embryos range in age from 65 to 70 h).