Fig. 2. Trunk to gnathal transformation is more complete in tsh mutant
embryos. Each panel shows a whole embryo image and higher magnifications from
abdominal segments of two independent individuals. Ectopic structures are
indicated in the whole embryo images by arrowheads. (A) Wild-type larval
cuticle and normal maxillary structures. (B) Ventral cuticle of a terminal
homozygous tsh8 larva. Small spots of sclerotized material
(arrows in high-magnification panels) are occasionally present. (C) In the
trunk segments of prd
Dfd embryos, cirri and,
occasionally, rod-shaped sclerotic structures are present. (D)
tsh8, UAS-Dfd/tsh8; prd-Gal4/+ embryos
demonstrate a more complete transformation. Mouthpart-like material and cirri
are present in each affected segment, with well-shaped mouth hooks frequently
observed, though the ectopic sclerotized material also can lack a specific
shape. (E) tsh8, UAS-Dfd, UAS-disco/tsh8;
prd-Gal4/+ embryos exhibit a more consistent transformation. Mouth hooks
form in all expressing segments, and we did not observe amorphous sclerotized
material as seen in tsh8, UAS-Dfd/tsh8;
prd-Gal4/+ embryos shown in D. (F) In tsh8, UAS-Dfd,
UAS-disco/tsh8; arm-Gal4/+ embryos, the
trunk-to-maxillary transformation is striking, with ectopic maxillary
structures appearing in virtually all segments.