A locus control region (LCR) is a long-range cis-regulatory element that enhances expression of linked genes at distal chromatin sites.
It functions in a copy number-dependent manner and is tissue-specific, as seen in the selective expression of β-globin genes in erythroid cells.
[1] Transcription factors bind to hypersensitive site cores and cause the LCR to form a loop that can interact with the promoter of the gene it regulates.
[1] Transcription factors bind to DNA from the LCR to the promoter in an orderly fashion using non-DNA-binding proteins and chromatin modifiers.
[1] Studies in transgenic mice have shown that deletion of the β-globin LCR causes the region of chromosome to condense into a heterochromatic state.