A new model for long-range chromatin reorganization linked to enhancer activation [Agilent_RNA]

The most prominent model for long-range enhancer regulation involves direct enhancer-promoter interaction by looping out the intervening chromatin. Using a synthetic biology approach, we have determined that a chromatin unfolding bteween Shh and its enhancers is regulated specifically by the Shh-Brain-Enhancers and is mediated by the recruitment of Poly (ADP-Ribose) Polymerase 1. This ‘chromatin unfolding’ model represents a new mechanism of long-range enhancer-promoter communication in addition to the looping and tracking models. RNA-on-chip for probing nuclear RNA on the Shh regulatory region on ESCs and NPC showed no spreading of nuclear RNA in the regulatory region upon Shh activation. Comparison of ESCs and NPC nuclear RNA profiles on Shh region