Fig. 1: The gene regulatory landscape from a linear and three-dimensional perspective.
From: Interpreting the impact of noncoding structural variation in neurodevelopmental disorders
(a) Genetic locus, illustrating the regulatory function of multiple noncoding elements. The region is delimited by topologically associated domain (TAD) boundaries on either side, each consisting of a cluster of CTCF binding sites. A protein-coding sequence is flanked by a promoter and 5’ and 3’ untranslated region (UTR). An intergenically transcribed long noncoding RNA (lncRNA) performs its regulatory function by acting as a scaffold for the binding of transcription factors (TFs). The activity of multiple enhancer elements in the locus is tissue- and even cell-type-dependent. (b) Via a loop extrusion mechanism, anchored by the CTCF-bound TAD boundaries, the functional elements in the locus are brought into close physical proximity, allowing interaction between the promoter and active enhancers and the assembly of the transcriptional machinery.
