Fig. 6. The At-dpp RNAi embryos exhibit defects in formation of the extra-embryonic area and germ band. (A-E,A'-E') Time course of a developing At-dpp RNAi embryo. (F-H,F'-H') Time course of a developing normal embryo. Images were taken at the time points indicated (day: hour: minute). For both embryos, time point 0:00:00 is adjusted to mid-stage 5, when the cumulus (arrows) is midway through shifting. The images in A-E, F-H show posterior views (or the top of the germ disc), and those in A',B',F'-H' show lateral views with the posterior to the bottom. The DV orientation of the embryo shown in C'-E' could not be determined, but the posterior side is to the bottom. Arrows in A,A',B,B',F,F' indicate the cumulus, and arrowheads in G,G',H indicate the expanding extra-embryonic area (ex) in the normal embryo. Since the cells at the extra-embryonic area are very thin, the yolk mass is seen through them. By contrast, the embryonic area or the germ band (gb) is seen as opaque (or white) material. Note that the extra-embryonic area is not formed in the At-dpp RNAi embryo (C-E,C'-E'). (I) RT-PCR comparison of the levels of At-dpp, At-sog, ef1 and histone H3 transcripts in At-dpp RNAi (dpp Ri) and untreated (u.t.) embryos at stage 5. `+' and `-' indicate reactions with and without reverse transcriptase, respectively. Note that a faint band of At-dpp transcripts is visible in the `+' lane of the At-dpp RNAi sample. Scale bar: 100 µm.