Lineage-specific compaction of Tcrb requires a chromatin barrier to protect the function of a long-range tethering element.

Journal Article

Gene regulation relies on dynamic changes in three-dimensional chromatin conformation, which are shaped by composite regulatory and architectural elements. However, mechanisms that govern such conformational switches within chromosomal domains remain unknown. We identify a novel mechanism by which cis-elements promote long-range interactions, inducing conformational changes critical for diversification of the TCRβ antigen receptor locus (Tcrb). Association between distal Vβ gene segments and the highly expressed DβJβ clusters, termed the recombination center (RC), is independent of enhancer function and recruitment of V(D)J recombinase. Instead, we find that tissue-specific folding of Tcrb relies on two distinct architectural elements located upstream of the RC. The first, a CTCF-containing element, directly tethers distal portions of the Vβ array to the RC. The second element is a chromatin barrier that protects the tether from hyperactive RC chromatin. When the second element is removed, active RC chromatin spreads upstream, forcing the tether to serve as a new barrier. Acquisition of barrier function by the CTCF element disrupts contacts between distal Vβ gene segments and significantly alters Tcrb repertoires. Our findings reveal a separation of function for RC-flanking regions, in which anchors for long-range recombination must be cordoned off from hyperactive RC landscapes by chromatin barriers.

Full Text

Duke Authors

Cited Authors

  • Majumder, K; Koues, OI; Chan, EAW; Kyle, KE; Horowitz, JE; Yang-Iott, K; Bassing, CH; Taniuchi, I; Krangel, MS; Oltz, EM

Published Date

  • January 2015

Published In

Volume / Issue

  • 212 / 1

Start / End Page

  • 107 - 120

PubMed ID

  • 25512470

Electronic International Standard Serial Number (EISSN)

  • 1540-9538

International Standard Serial Number (ISSN)

  • 0022-1007

Digital Object Identifier (DOI)

  • 10.1084/jem.20141479

Language

  • eng