Figure 2. INA-1 Recognizes Apoptotic Cells and Is Required for Their Internalization by Engulfing Cells. (Aa-Aj) INA-1::GFP is enriched in the pseudopods extending around apoptotic cells. Time-lapse images of INA-1::GFP (Aa-Ae) and differential interference contrast (DIC; Af-Aj) during cell corpse internalization in an embryo expressing Pced-1ina-1::gfp are shown. 0 min indicates the time point at which INA-1::GFP was first seen to accumulate at the contact site with C3. Arrowheads indicate the apoptotic cell (C3); arrows indicate the engulfing cell (ABplaapppp). Scale bar in (Aa) represents 5 μm.(Ba-Bc)
ina-1 mutations reduce the efficiency of cell corpse internalization in engulfing cells.(Ba and Bb) MYRI::GFP and DIC images of wild-type (Ba) and
ina-1(
gm144) (Bb) embryos expressing Pced-1myri::gfp. Arrows indicate apoptotic cells. Scale bar in (Ba) represents 5 μm.(Bc) Percentage of apoptotic cells with a MYRI::GFP circle in the indicated genotype. Data (mean ± SD) are the average for two independent transgenic lines. Numbers in parentheses indicate the number of cell corpses scored.(Ca-Cc) INA-1(N) binds to the surface of apoptotic cells in a
scrm-1-dependent manner.(Ca and Cb) INA-1(N)::GFP and DIC images of
ced-1(
e1735);
ced-5(
n1812) (Ca) and
scrm-1(RNAi)ced-1
(e1735);
ced-5(
n1812) (Cb) embryos expressing Phspina-1(N)::gfp. Arrows indicate apoptotic cells. Scale bar in (Ca) represents 5 μm.(Cc) Percentage of INA-1(N)::GFP+ cell corpses in the indicated genotype. Cell corpses fully enclosed by the INA-1(N)::GFP circle were scored as INA-1(N)::GFP+. Each sample point represents the data from 12 embryos. Data are shown as mean ± SD.