Paused Pol II captures enhancer activity and acts as a potent insulator.
Enhancers act over many kilobase pairs to activate target promoters, but their activity is constrained by insulator elements that prevent indiscriminate activation of nearby genes. In the July 1, 2009, issue of Genes & Development, Chopra and colleagues (pp. 1505-1509) report that promoters containing a stalled Pol II are activated by enhancers, but these promoters also serve as insulators that block enhancers from reaching more distal genes. This new class of insulators provide critical clues to regulatory mechanisms.
Core
Leighton J
LJ
Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA.
Lis
John T
JT
D000818:Animals; D004257:DNA Polymerase II / Q000378:metabolism*; D004742:Enhancer Elements, Genetic / Q000502:physiology*; D005786:Gene Expression Regulation; D038101:Insulator Elements / Q000502:physiology*
D004257:DNA Polymerase II