DT40 knock-out and knock-in studies determine the regions necessary and sufficient for transcription and epigenetic conversion of the chicken Ig-β gene.

The chicken Ig-β locus is organized by three cell-type-specific genes and two ubiquitously expressed genes. B-cell-specific DNase I hypersensitive sites (DHS) in that locus, including three present inside the flanking gene, were grouped into six regions and deleted. The deletions decreased Ig-β mRNA content to <0.