The endogenous BigH1 locus has been modified, such that the BigH1 N-terminal and C-terminal domains have been replaced by the equivalent regions of His1. In addition, three copies of the Tag:FLAG epitope have been inserted at the N-terminal end of the open reading frame. A loxP cassette carrying a Disc\RFPDsRed.3xP3.cUa marker has also been inserted, downstream of the BigH1 transcription unit.