abstract:Locus control regions (LCR) are defined by their ability to enhance the expression of linked genes to physiological levels in a tissue-specific and copy number-dependent manner at ectopic chromatin sites. The concept derives from the idea that developmental and cell lineage-specific regulation of gene expression relies not only on gene-proximal elements such as promoters, enhancers, and silencers, but also on long-range interactions of various cis-regulatory elements and dynamic chromatin alterations.