A 32kb genomic BAC fragment that encompasses brk. There are 13 potential silencer elements (SEs) in the brk regulatory sequences (12 upstream of the coding sequence, one downstream); in this transgene, each of the SE sites except site 6 has been made non-functional by introducing five point mutations that completely abrogate binding of Mad, Med and shn proteins in vitro (numbering of sites is distal to proximal). A multi-tag cassette composed of 2xTag:FLAG, 3xTag:HA and Tag:StrepII has been inserted at the C-terminal end of the brk coding sequence. An FRT cassette that encodes the EGFP coding sequence followed by stop sequences has been inserted in the brk 5'UTR. In the absence of FLP recombinase, the EGFP sequence is expressed under the control of endogenous brk regulatory sequences, and the brk coding sequence is not expressed.

A 32kb genomic BAC fragment that encompasses brk. There are 13 potential silencer elements (SEs) in the brk regulatory sequences (12 upstream of the coding sequence, one downstream); in this transgene, each of the SE sites except site 6 has been made non-functional by introducing five point mutations that completely abrogate binding of Mad, Med and shn proteins in vitro (numbering of sites is distal to proximal). A multi-tag cassette composed of 2xTag:FLAG, 3xTag:HA and Tag:StrepII has been inserted at the C-terminal end of the brk coding sequence. An FRT cassette that encodes the EGFP coding sequence followed by stop sequences has been inserted in the brk 5'UTR. In the absence of FLP recombinase, the EGFP sequence is expressed under the control of endogenous brk regulatory sequences, and the brk coding sequence is not expressed.