Functions of E2A-HEB heterodimers in T-cell development revealed by a dominant negative mutation of HEB.

Published

Journal Article

Lymphocyte development and differentiation are regulated by the basic helix-loop-helix (bHLH) transcription factors encoded by the E2A and HEB genes. These bHLH proteins bind to E-box enhancers in the form of homodimers or heterodimers and, consequently, activate transcription of the target genes. E2A homodimers are the predominant bHLH proteins present in B-lineage cells and are shown genetically to play critical roles in B-cell development. E2A-HEB heterodimers, the major bHLH dimers found in thymocyte extracts, are thought to play a similar role in T-cell development. However, disruption of either the E2A or HEB gene led to only partial blocks in T-cell development. The exact role of E2A-HEB heterodimers and possibly the E2A and HEB homodimers in T-cell development cannot be distinguished in simple disruption analysis due to a functional compensation from the residual bHLH homodimers. To further define the function of E2A-HEB heterodimers, we generated and analyzed a dominant negative allele of HEB, which produces a physiological amount of HEB proteins capable of forming nonfunctional heterodimers with E2A proteins. Mice carrying this mutation show a stronger and earlier block in T-cell development than HEB complete knockout mice. The developmental block is specific to the alpha/beta T-cell lineage at a stage before the completion of V(D)J recombination at the TCRbeta gene locus. This defect is intrinsic to the T-cell lineage and cannot be rescued by expression of a functional T-cell receptor transgene. These results indicate that E2A-HEB heterodimers play obligatory roles both before and after TCRbeta gene rearrangement during the alpha/beta lineage T-cell development.

Full Text

Duke Authors

Cited Authors

  • Barndt, RJ; Dai, M; Zhuang, Y

Published Date

  • September 2000

Published In

Volume / Issue

  • 20 / 18

Start / End Page

  • 6677 - 6685

PubMed ID

  • 10958665

Pubmed Central ID

  • 10958665

International Standard Serial Number (ISSN)

  • 0270-7306

Digital Object Identifier (DOI)

  • 10.1128/mcb.20.18.6677-6685.2000

Language

  • eng

Conference Location

  • United States