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Updated: Jun 17, 2026

Streamlined Single Cell TCR Isolation and Generation of Retroviral Vectors for In Vitro and In Vivo Expression of Human TCRs
Published on: September 10, 2017
TCR beta feedback signals inhibit the coupling of recombinationally accessible V beta 14 segments with DJ beta
Katherine S Yang-Iott1, Andrea C Carpenter, Marta A W Rowh
1Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
Abstract:
Ag receptor allelic exclusion is thought to occur through monoallelic initiation and subsequent feedback inhibition of recombinational accessibility. However, our previous analysis of mice containing a V(D)J recombination reporter inserted into Vbeta14 (Vbeta14(Rep)) indicated that Vbeta14 chromatin accessibility is biallelic. To determine whether Vbeta14 recombinational accessibility is subject to feedback inhibition, we analyzed TCRbeta rearrangements in Vbeta14(Rep) mice containing a preassembled in-frame transgenic Vbeta8.2Dbeta1Jbeta1.1 or an endogenous Vbeta14Dbeta1Jbeta1.4 rearrangement on the homologous chromosome. Expression of either preassembled VbetaDJbetaC beta-chain accelerated thymocyte development because of enhanced cellular selection, demonstrating that the rate-limiting step in early alphabeta T cell development is the assembly of an in-frame VbetaDJbeta rearrangement. Expression of these preassembled VbetaDJbeta rearrangements inhibited endogenous Vbeta14-to-DJbeta rearrangements as expected. However, in contrast to results predicted by the accepted model of TCRbeta feedback inhibition, we found that expression of these preassembled TCR beta-chains did not downregulate recombinational accessibility of Vbeta14 chromatin. Our findings suggest that TCRbeta-mediated feedback inhibition of Vbeta14 rearrangements depends on inherent properties of Vbeta14, Dbeta, and Jbeta recombination signal sequences.
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