Fig. 1. GPA-16 distribution in early embryos. (A) Western blot analysis using GPA-16 antibodies on wild-type or gpa-16(RNAi) embryonic extracts. The blot was reprobed with -tubulin antibodies as a loading control (bottom). (B-H) Wild-type embryos (B, one-cell stage late telophase; C, four-cell stage), as well as four-cell stage embryos of the indicated genotypes stained with antibodies against GPA-16 (red) and -tubulin (green); DNA is shown in blue. Left panels show GPA-16 staining alone, right panels the merge of the three signals. Rectangles highlight a region of the cortex at the ABp/EMS boundary to ease comparison of GPA-16 levels; this region does not exhibit the variability in staining intensity sometimes observed on the cortex facing the outside. Insets represent 2.5x magnified view of the approximate region indicated by the rectangles. Analogous distributions are observed in one-cell stage embryos (data not shown). Arrows in C,D indicate signal around microtubule asters, which persists in gpa-16(RNAi) embryos. In this and other figures, anterior is leftwards, posterior is rightwards. Scale bar: 10 µm.