Insulated neighborhood

In mammalian biology, insulated neighborhoods are chromosomal loop structures formed by the physical interaction of two DNA loci bound by the transcription factor CTCF and co-occupied by cohesin.

Insulated neighborhoods are defined as chromosome loops that are formed by CTCF homodimers, co-bound with cohesin, and containing at least one gene.

One study in human Embryonic stem cells identified ~13,000 insulated neighborhoods that, on average, each contained three genes and was about 90kb in size.

The majority of insulated neighborhoods appear to be maintained during development because CTCF binding and CTCF-CTCF loop structures are very similar across human cell types.

[23] Studies of imprinted loci showed DNA methylation controls CTCF-anchored loops regulating gene expression.

Chromosomal alterations such as translocations, deletions and tandem duplications intersecting with insulated neighborhood anchor sites can activate oncogenes.

Multiple levels of mammalian genome organization. Chromosomes occupy discrete territories in the nucleus (left). Topologically associating domains (TADs) are regions of the genome with locally high interaction frequency (center). Insulated neighborhoods are loops formed by the interaction of CTCF/cohesin-bound anchors containing genes and their regulatory elements.