Fig. 3. (A) Schematic representation of the mCSKA minimal promoter constructs. The 785 bp MRR (yellow) was cloned in front of the mCSKA minimal promoter (101 bp shown in blue) driving the expression of GFP (shown in green) to create the transgene MRRmCSKAGFP. The numbers 1, 2 and 3 illustrate the position of the 3 putative HBX sites. (B) Expression of MRRmCSKAGFP and deletion derivatives at the gastrula stage. Expression was analysed by mRNA in situ hybridisation to GFP. All embryos are orientated with dorsal pointing up and the vegetal pole facing out.