Figure 4.12. T-cell receptor α- and β-chain gene rearrangement and expression.

Figure 4.12T-cell receptor α- and β-chain gene rearrangement and expression

The TCRα- and β-chain genes are composed of discrete segments that are joined by somatic recombination during development of the T cell. Functional α- and β-chain genes are generated in the same way that complete immunoglobulin genes are created. For the α chain (upper part of figure), a Vα gene segment rearranges to a Jα gene segment to create a functional V-region exon. Transcription and splicing of the VJα exon to Cα generates the mRNA that is translated to yield the T-cell receptor α-chain protein. For the β chain (lower part of figure), like the immunoglobulin heavy chain, the variable domain is encoded in three gene segments, Vβ, Dβ, and Jβ. Rearrangement of these gene segments generates a functional VDJβ V-region exon that is transcribed and spliced to join to Cβ; the resulting mRNA is translated to yield the T-cell receptor β chain. The α and β chains pair soon after their biosynthesis to yield the α:β T-cell receptor heterodimer. Not all J gene segments are shown, and the leader sequences preceding each V gene segment are omitted for simplicity.

From: T-cell receptor gene rearrangement

Cover of Immunobiology
Immunobiology: The Immune System in Health and Disease. 5th edition.
Janeway CA Jr, Travers P, Walport M, et al.
New York: Garland Science; 2001.
Copyright © 2001, Garland Science.

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