The Poxn upstream region (extending to -8202 relative to the transcription start site, includes the brain enhancer) and 5' UTR sequence (lacking intron) is fused upstream of Tag:M(mCd8a)-tagged EGFP. Some out-of-frame Poxn coding sequence (from exon 5) plus the 3'UTR sequence is present downstream of the EGFP sequence.