Posttranslational regulation of TCR Valpha allelic exclusion during T cell differentiation.
Published
Journal Article
We have previously shown that phenotypic allelic exclusion of TCR alpha-chain is functional only in mature thymocytes. A significant proportion of immature thymocytes (TCRlow) express more than one cell surface alpha-chain, but mature thymocytes (TCRhigh) show phenotypic allelic exclusion and express only a single alpha-chain. We have analyzed thymocytes for both surface and intracellular alpha-chain expression and find that the majority of mature thymocytes express a second alpha-chain intracellularly. This result is predicted by a model in which the developmentally regulated allelic exclusion of the TCR alpha-chain is caused by competition between alpha-chains for the beta-chain rather than by models in which one alpha-chain is down-regulated or in which selection favors cells with only a single alpha-chain species. Changes in the relative amounts of alpha- and beta-chains available for pairing may therefore allow competition between the two alpha-chains for the beta-chain. Peripheral T cells also frequently express second alpha-chains in the cytoplasm (18-27%), despite a rather low frequency of dual alpha-chain expression on the cell surface (2-4%). The frequency of nonsurface expressed alpha-chains is reduced somewhat compared with thymocytes, indicating that an additional level of control of allelic exclusion operates during the maturation of peripheral T cells.
Full Text
Duke Authors
Cited Authors
- Alam, SM; Gascoigne, NR
Published Date
- April 15, 1998
Published In
Volume / Issue
- 160 / 8
Start / End Page
- 3883 - 3890
PubMed ID
- 9558094
Pubmed Central ID
- 9558094
International Standard Serial Number (ISSN)
- 0022-1767
Language
- eng
Conference Location
- United States