The His3 promoter, amino acids 1-62 of the His3 open reading frame (ORF) and the His3 3' end containing a portion of the downstream intergenic region (from immediately after the stop codon through until 18bp downstream of the HDE) are fused upstream of the EGFP ORF. The His3 ORF is in frame with the EGFP ORF. A single mutation (U to A) has been introduced within the HDE in order to disrupt a stop codon.
The EGFP open reading frame (ORF) and a poly(A) site is fused downstream of a fragment consisting of the His3 promoter and the first 62 amino acids of the His3 ORF fused to the 3'UTR of His3 (which includes the stem loop and histone downstream element (HDE) sequences but not the downstream polyadenylation signals).