| First Author | Majumder K | Year | 2015 |
| Journal | J Exp Med | Volume | 212 |
| Issue | 1 | Pages | 107-20 |
| PubMed ID | 25512470 | Mgi Jnum | J:301508 |
| Mgi Id | MGI:6204150 | Doi | 10.1084/jem.20141479 |
| Citation | Majumder K, et al. (2015) Lineage-specific compaction of Tcrb requires a chromatin barrier to protect the function of a long-range tethering element. J Exp Med 212(1):107-20 |
| abstractText | 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 TCRbeta antigen receptor locus (Tcrb). Association between distal Vbeta gene segments and the highly expressed DbetaJbeta 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 Vbeta 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 Vbeta 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. |
