(A,B) Homozygous axin mutant flies are fully rescued by co-expression of AxinΔRGS and AxinH504L. (A) A male fly displaying no defects; the wild type wings with intact wing margins (arrows) and fully formed legs with tarsal claws at their distal tip (arrowheads) are indicated. (B) The abdomen of a female shows the wild type pattern of sternites and their bristles (arrows).
(C,D) Homozygous axin mutant flies rescued by co-expression of the point mutants AxinK446E and AxinH504L. (C) Wings (arrows) and legs with visible tarsal claws (arrowheads) are fully formed, as are sternites in the ventral abdomen shown in (D)(arrows).
(E–I) Schematic representation of wild type and mutant Axin complexes. (E) Wild type Axin recruits APC, Shaggy and Armadillo, which also interact with each other. (F) These additional interactions (red bars) allow the indirect recruitment of Armadillo into an AxinΔArm complex, and by extension into other deletion or point mutant complexes. (G) Dimerization (red bars) between two Axin mutants AxinΔArm and AxinΔRGS restores a functional complex (Peterson-Nedry et al., 2008). (H) Similarly, complementation between AxinH504L and AxinΔRGS rescues, as shown in (A,B), and co-expression of AxinH504L with the Shaggy binding domain mutant AxinK446E also rescues (see panels C,D). Models are modified from Peterson-Nedry et al. (2008).