TCRGene

TCRGene is a term used in genomics and immunology to refer to genes associated with the T-cell receptor (TCR). It is not a single, fixed gene but a generic label that may denote the various genetic elements that encode TCR chains across the four TCR loci. In humans, the functional TCR genes are organized into four loci: TCRA (TRA) and TCRD (TRD) on chromosome 14, and TCRB (TRB) and TCRG (TRG) on chromosome 7. The TRD locus is embedded within the TRA locus, reflecting a shared genomic arrangement.

Each locus contains multiple gene segments arranged in clusters. The alpha and gamma loci primarily include variable (V), joining (J), and constant (C) segments, while the beta and delta loci include variable, diversity (D), joining, and constant segments. The combinatorial use of these segments, along with junctional diversification, underpins the diversity of T-cell receptors.

Expression of TCR genes occurs during T-cell development in the thymus. V(D)J recombination—mediated by the RAG1/RAG2 enzymes—rearranges V, D (where present), and J segments to create a functional TCR chain. The resulting receptor chains pair with CD3 to form a complete TCR complex, capable of recognizing peptide antigens presented by MHC molecules. The hypervariable CDR3 region, formed at V(D)J junctions, plays a central role in antigen specificity.

Nomenclature for individual TCR genes follows standardized prefixes (for example, TRAV, TRBV, TRGV, TRDV, TRAC, TRDC, TRBC, TRGC). In practice, TCRGene can serve as a placeholder in databases or pipelines referring to these TCR gene elements. See also T-cell receptor, V(D)J recombination, and immunogenetics.

---