Figure 2.

Shavenbaby embryonic expression is generated by the activity of multiple transcriptional enhancers. (a) Expression pattern of shavenbaby in the epidermis of a late stage Drosophila melanogaster embryo. (b) Schematic view of the structure of the svb/ovo locus. Black boxes indicate svb embryonic enhancers and grey boxes demarcate exons. The exons present in the svb mRNA are shown below this scheme. Svb protein contains a dominant repressor domain, an activator domain and a DNA-binding domain. The arrow marks the position where Svb is truncated, which converts Svb into a transcriptional activator. (c) Seven transcriptional enhancers generate the expression pattern of shavenbaby in the embryonic epidermis. The black regions within trichome domains schematize the expression patterns of enhancers DG2, DG3, Z, A, E3, E6 and 7. (Online version in colour.)