Fig. 4.

Tc-tiotsh expression in Tribolium embryos. Engrailed expression is shown in brown, while Tc-tiotsh expression is in purple. Embryos are oriented with anterior to the left (except in panel d in which anterior is to the top). a During germband elongation, Tc-tiotsh is expressed in the gnathal and trunk segments as well as two procephalic regions (the intercalary segment [Ic] and the labrum [Lr]). b When germband elongation is completed, Tc-tiotsh expression is strongest in the thoracic (T1–T3) and first abdominal (A1) segments. c Slightly later, strong Tc-tiotsh expression appears in the posterior terminal region of the embryo (arrowhead). dTc-tiotsh is expressed in only the proximal portion (arrow) of the developing legs. e In embryos undergoing germ-band retraction, Tc-tiotsh expression is present in the six Malpighian tubule primordia that evert from the hindgut. f In a Df(HOMC) homozygote lacking most Hox genes, Tc-tiotsh expression in the segmented portion of the germband is greatly reduced. In contrast, expression in the Malpighian tubule primordia remains strong