DNA binding protein and sequence as insulators having specific enhancer blocking activity for regulation of gene expression

摘要

An insulator element shown to be both necessary and sufficient for the enhancer blocking activity in human cells is described. The insulator element of the invention is a 42 base pair DNA molecule having specific enhancer blocking activity for regulation of gene expression. The insulator element has also been shown to be the core binding site for CTCF, a DNA binding protein that is highly conserved in vertebrates. In addition, an insulator element containing CTCF binding sites has been identified in the region of the Igf 2 locus which is methylated exclusively on the paternal allele. Methylation of the insulator sequence abolishes the ability of CTCF to bind to the insulator and results in loss of enhancer-blocking activity.