Fig. 4. Terminal phenotypes and cell type abundance in mip(RNAi) embryos. The DIC micrographs in the top row show that mex-3, mex-6 and spn-4 RNAi embryos produce differentiated cell types but do not undergo morphogenesis. In the remaining rows, body wall muscle, epidermis, intestine, pharynx and neurons were visualized as described in Materials and Methods. mex-3, mex-6 and spn-4 RNAi embryos produce excess body wall muscle and epidermal cells. mex-3 and spn-4 RNAi embryos produce a normal amount of intestine but reduced pharynx, while mex-6(RNAi) embryos produce no intestine and excess pharynx. By the time the neural GFP marker was expressed, neural tissue was dispersed throughout the embryo, making it difficult to judge the amount of neural tissue. Thus, we conclude only that neural tissue is present in mex-3, mex-6 and spn-4 RNAi embryos and do not make any conclusions about the relative amount. For all embryos, some fluorescent signal is out of the plane of focus. This is most noticeable in the intestine micrographs, where the wild-type intestine has elongated but the mex-3 and spn-4 RNAi intestine has not.