Contains ovo-B regulatory sequences (from -830 to the transcription start site), the ovo-B 5'UTR, cDNA encoding ovo-B (ovo-RD) and the ovo-B 3'UTR. An FRT cassette containing 2 SV40 transcription termination sequences has been inserted in the 5'UTR sequence; this means that in the absence of FLP recombinase, ovo-B protein is not expressed from this transgene. If the FRT cassette is excised using FLP recombinase, ovo-B protein is expressed.