Rr320^tm5Mkg

A targeting vector was designed to remove 5'HS4 encoded by nucleotides -19849 to -22561 relative to the Ey cap site. The removed sequence includes the core binding site, the region to which the HS maps and all regions of homology with human 5'HS1, however, three small blocks of homology of 7, 11, and 7 bp, upstream of the HS core remained after targeting. A loxP site flanked neomycin resistance gene cassette was included in the vector. The presence of the marker had a substantial effect on expression of beta-like globin genes at all stages. (J:106655)