The Drosophila Cadherin Fat Regulates Tissue Size and Planar Cell Polarity through Different Domains
Figure 3
The H2 region is necessary and sufficient for viability and tissue size regulation.
(A) Sequence alignment of cytoplasmic domain of Drosophila Ft (538 a.a.) and human Ft4 (452 a.a.) reveals highly conserved regions (conserved block 1–5) shown in blue boxes. The starting and ending positions of the deletion mutants are indicated by red bars. (B) Schematic structure of Ft intracellular domain deletion mutants is on the left. Myristylation sequence is indicated in orange. Conserved homology regions are indicated in blue. V5 tag is indicated in pink. Regions deleted are shown with black lines. Quantification of the lethality rescue and disc size rescue on the right. (See Fig. 2AB for method details) (C) Expression levels of intracellular domain deletion mutants are revealed by an immunoblot of imaginal disc extracts from ft mutant animals expressing various transgenes. Blots were probed with anti-V5 and anti-β-tubulin. (D–F) Deletion of the H2 region in either the intracellular domain (E) or the full-length Ft protein (F) effectively abolished rescuing ability, whereas the H2 region, when membrane localized (D), is necessary and sufficient to rescue both lethality and disc size overgrown phenotype. Third-instar eye imaginal discs were stained with fluorescein phalloidin. Genotypes are: (D) ft−/−;TubP-Gal4/UAS-MH2, (E) ft−/−; TubP-Gal4/UAS-MΔH2, (F) ft−/−; TubP-Gal4/UAS-FL-ΔH2.