Biochemistry Questions / Explain the concept of topologically associated domains (TADs) and their regulation by CTFC and cohesin.

Topologically associated domains (TADs) are regions of chromosomes that are co-ordinately regulated and replicated. TAD boundaries are established by CTCF and cohesin, allowing the formation of gene loops on heterochromatin to allow transcription. TADs are flanked by lamina associated domains (LADs), which are regions of the chromosome that are bound to the nuclear lamina. These sections (LADs) are transcriptionally silent, and are tethered to the nuclear periphery.