An approximately 4.5kb Kr regulatory fragment from upstream of the Kr transcription start site is fused upstream of the Kr core promoter (sequence extends to the beginning of the second exon) followed by 24 copies of the Tag:MS2 stem loop and lacZ. The proximal (CD2) blastoderm enhancer normally present in the Kr regulatory fragment has been replaced with distal (CD1) blastoderm enhancer sequence, thus the regulatory fragment contains two copies of the CD1 enhancer.