Figure 5
Expression of ApVas1 during germ band extension, katatrepsis, and late embryogenesis. Dissected embryos were collected from 2 to 42 dAEL. Before katatrepsis (A-H): embryonic anterior, right; after katatrepsis (I): embryonic anterior, left. ApVas1 stripes: brackets. (A-C) Germ band extension. (A) Embryos at 2 dAEL of development. ApVas1 stripe and bacteria were co-localized to the posteriormost region of the germ band. (B, C) Embryos at 3 to 5 dAEL of development. Bacteria migrated through the ApVas1 stripe, locating posteriorly to the ApVas1 stripe. (D-F) Morphogenesis of the germ band. (D, E) Embryos at 6 to 7 dAEL of development. Structures of the cephalic lobe, thorax, and abdomen could be identified. Cephalic lobe in (E) was truncated; see Additional file 8: Figure S8B, D for intact morphology. (F) Embryos at 14 dAEL of development. Segments in the head and thorax were visible. During 6 to 14 dAEL, the ApVas1 stripe was reorganized into a globular shape. (G-I) Fully-segmented embryos before and after katatrepsis. Dorsal view of embryos attached with bacteria is presented, and follow the style of Miura et al. and Shingleton et al. [46, 52]. (G) Embryos at 25 dAEL of development. ApVas1-positive cells associated with the bacteria were located to the posteriormost region of the embryo, forming a ‘U’ shaped cap. (H) Embryos at 35 dAEL of development. ApVas1-positive cells were bilaterally located in the abdomen. Another embryo at similar age in lateral view was shown in Additional file 7: Figure S7A. (I) Embryos at 42 dAEL of development (after katatrepsis). The distribution of ApVas1-positive cells remained similar to that seen in embryos of 35 dAEL. (G’-I’) Schematic illustrations shown in (G-I). Abbreviations: ab, abdomen; b, bacteria; cl, cephalic lobe; ey, eyes; gb, germ band; h, head; th, thorax; y, yolk. Scale bars: 100 μm.