Fig. 3. GATAa specifies epidermis. (A) Expression of the epidermis markers epiB and epi1 in control and EnR-GATAa mRNA-injected embryos. Embryos shown in the top and middle panels were cleavage-arrested at the 64-cell stage with cytochalasin and stained at the equivalent of the neurula stage for the presence of epi1 or epiB transcripts (animal view, anterior to the top). Embryos shown in the bottom panels were left to cleave normally and stained at the early tailbud stage for epi1 transcripts. (B) Expression of epiB at late gastrula stage in control and GATAa-MO, GATAb-MO or double-injected embryos. Numbers indicate the proportion of positive embryos. Percentages refer to embryos with strongly reduced expression.