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. 2009 Oct 23;4(10):e7574. doi: 10.1371/journal.pone.0007574

Figure 3. Overexpression of Rheb in distal leg segments results in a strongly penetrant malformed leg phenotype.

Figure 3

(A) Model of the PI3K/Tor signaling pathway. Details of the pathway are found in the text. (B) Control animals, in this case heterozygous for UAS-PI3K92E.CAAX, but without a GAL4 driver, show normal leg morphology in live adults. Similarly, Dll-GAL4/+ and UAS-Rheb/+ adults have no leg malformations (not shown). (C) UAS-PI3K92E.CAAX/+; Dll-GAL4/+ animals express activated PI3K in distal leg segments (distal to the arrow) that results in a growth advantage giving the adults a “Popeye” leg phenotype. The most common morphogenesis defect is a slightly short, fat first tarsal segment (arrowhead). (D and E) Dll-GAL4/+; UAS-Rheb/+ adults show a highly penetrant malformed leg phenotype independent of the “Popeye” growth phenotype. Mild phenotypes include moderate to extreme short fat distal tibia and tarsal segments (arrowhead in E), whereas more extreme phenotypes include severely misshapen and twisted segments (arrowhead in D). The edges of the wings are often curved while the overall size of the wing is reduced. These defects are often accompanied by severe bends in the femur (white asterisk in E), even though the transgene is not expressed in this segment.