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The human T-cell receptor gamma (TRG) genes
Trends in Biochemical Sciences
|June 1, 1989
Summary
Human T-cell receptor gamma (TRG) genes rearrange in T cells. The TRG locus includes variable and constant genes, forming gamma-chains expressed on T lymphocytes, but their exact function requires further study.
Area of Science:
- Immunology
- Genetics
- Molecular Biology
Background:
- T-cell receptor (TCR) gamma (TRG) chain genes, similar to TCR alpha and beta genes, undergo specific rearrangements within T cells.
- The human TRG locus has been fully mapped, revealing its genetic architecture.
Purpose of the Study:
- To detail the genetic composition of the human TRG locus.
- To describe the expression and potential function of the gamma-chain in T lymphocytes.
Main Methods:
- Genetic mapping of the human TRG locus.
- Analysis of TRG gene rearrangement and expression in T cells.
Main Results:
- The human TRG locus comprises two constant region genes (TRGC), five joining segments (TRGJ), and at least 14 variable gamma-genes (TRGV).
- Eight TRGV genes are functional, categorized into four distinct subgroups.
- The rearranged TRG gene product, the gamma-chain, is expressed with the delta-chain on a subset of T lymphocytes (gamma delta + cells).
Conclusions:
- The human TRG locus is well-defined, containing multiple variable and joining gene segments.
- Gamma delta T cells express gamma-chains, suggesting a role in immune responses, though their precise function remains unclear and warrants further investigation.