Visualization and quantification of monoallelic TCRα gene rearrangement in αβ T cells. Issue 5 (14th January 2014)

• Record Type: Journal Article
• Authors: Winter, Manuel; Kashani, Elham; Chennupati, Vijaykumar; Föhse, Lisa; Prinz, Immo
• Is Part Of: Immunology and cell biology. Volume 92:Issue 5(2014)
• Page Start: 409
• Page End: 416
• Publication Date: 2014-01-14
• Subjects: episomal reintegration -- monoallelic TCR rearrangement -- T‐cell development -- V(D)J recombination; Immunology -- Periodicals; Cytology -- Periodicals; 616.079
• DOI: 10.1038/icb.2013.105
• Languages: English
• ISSNs: 0818-9641

Abstract

Abstract : T‐cell receptor α (TCRα) chain rearrangement is not constrained by allelic exclusion and thus αβ T cells frequently have rearranged both alleles of this locus. Thereby, stepwise secondary rearrangements of both TCRα loci further increase the odds for generation of an α‐chain that can be positively selected in combination with a pre‐existing TCRβ chain. Previous studies estimated that approximately 2–12% of murine and human αβ T cells still carry one TCRα locus in germline configuration, which must comprise a partially or even fully rearranged TCRδ locus. However, these estimates are based on a relatively small amount of individual αβ T‐cell clones and αβ T‐cell hybridomas analyzed to date. To address this issue more accurately, we made use of a mouse model, in which a fluorescent reporter protein is introduced into the constant region of the TCRδ locus. In this TcrdH2BeGFP system, fluorescence emanating from retained TCRδ loci enabled us to quantify monoallelically rearranged αβ T cells on a single‐cell basis. Via fluorescence‐activated cell sorting analysis, we determined the frequency of monoallelic TCRα rearrangements to be 1.7% in both peripheral CD4 + and CD8 + αβ T cells. Furthermore, we found a skewed 5′ Jα gene utilization of the rearranged TCRα allele in T cells with monoallelic TCRα rearrangements. This is in line with previous descriptions of a tight interallelic positional coincidence of Jα gene segments used on both TCRα alleles. Finally, analysis of T cells from transgenic mice harboring only one functional TCRα locus implied the existence of very rare unusual translocation or episomal reintegration events of formerly excised TCRδ loci.