The native Orc6 promoter and UASt regulatory sequences are fused upstream of a hybrid protein composed of the N-terminal 206 amino acids of Hsap\ORC6 fused to the C-terminal 52 amino acids of Orc6. The hybrid contains mutant (c.449 + 5G > A) human intron 4 inserted in the native position of the human part. The coding sequence is tagged at the C-terminal end with Tag:FLAG.