Regulation of TCR delta and alpha repertoires by local and long-distance control of variable gene segment chromatin structure.

Journal Article (Journal Article)

Murine Tcrd and Tcra gene segments reside in a single genetic locus and undergo recombination in CD4- CD8- (double negative [DN]) and CD4+ CD8+ (double positive [DP]) thymocytes, respectively. TcraTcrd locus variable gene segments are subject to complex regulation. Only a small subset of approximately 100 variable gene segments contributes substantially to the adult TCRdelta repertoire. Moreover, although most contribute to the TCRalpha repertoire, variable gene segments that are Jalpha proximal are preferentially used during primary Tcra recombination. We investigate the role of local chromatin accessibility in determining the developmental pattern of TcraTcrd locus variable gene segment recombination. We find variable gene segments to be heterogeneous with respect to acetylation of histones H3 and H4. Those that dominate the adult TCRdelta repertoire are hyperacetylated in DN thymocytes, independent of their position in the locus. Moreover, proximal variable gene segments show dramatic increases in histone acetylation and germline transcription in DP thymocytes, a result of super long-distance regulation by the Tcra enhancer. Our results imply that differences in chromatin accessibility contribute to biases in TcraTcrd locus variable gene segment recombination in DN and DP thymocytes and extend the distance over which the Tcra enhancer can regulate chromatin structure to a remarkable 525 kb.

Full Text

Duke Authors

Cited Authors

  • Hawwari, A; Krangel, MS

Published Date

  • August 15, 2005

Published In

Volume / Issue

  • 202 / 4

Start / End Page

  • 467 - 472

PubMed ID

  • 16087716

Pubmed Central ID

  • PMC2212846

International Standard Serial Number (ISSN)

  • 0022-1007

Digital Object Identifier (DOI)

  • 10.1084/jem.20050680


  • eng

Conference Location

  • United States