Figure 5

A stable Arm cleavage product persists in apoptotic cells. (A) Arm^Central antibody immunoprecipitates full length Arm; Full length Arm (M_r 110 kDa; indicated as Arm^Full) is immunoprecipitated (IP) by the Arm^Nterm or the Arm^Central antibody. In Western blots of these immunoprecipitates Arm^Full is detected by the Arm^Nterm antibody. DE-cadherin or Arm antibodies were used to immunoprecipitate proteins from embryo extracts (IP) as indicated. Immunoprecipitates were then subjected to Western blotting using Arm^Central antiserum. Anti Arm^Central detects full length Arm in the input lane (in) and in immunoprecipitates by all three antibodies. (B) Detection of Arm^ΔN in protein extracts of th¹⁰⁹ homozygous embryos. Western blot of protein extracts from th¹⁰⁹ heterozygous (wt) and th¹⁰⁹ homozygous embryos. Levels of Arm^Full are decreased in th¹⁰⁹ homozygous embryos and a short form of Arm with M_r ~90 kDa is detected corresponding to Arm^ΔN. Actin was used as loading control. (C-F) Localization of Arm^ΔN in th¹⁰⁹ homozygous embryos (45 min after onset of morphogenesis arrest) stained for Arm^Nterm (C), Arm^Central (D) and Dα-Cat (E). Arrows in (C-E) point to an apoptotic cell where full length Arm is absent from the plasma membrane but Arm^Central is still present (F) Merged image with Arm^Nterm in green, Arm^Central in red and Dα-Cat in blue. (G-J) th¹⁰⁹ homozygous embryo (60 min after onset of morphogenesis arrest) (inset in J) stained for (G) TUNEL, (H) Arm^Central and (I) Dα-Cat; (J) Overlay with TUNEL in green, Arm^Central in red and Dα-Cat in blue.