Synonym(s)
DefinitionThis section has been translated automatically.
The TRAC gene (TRAC stands for T Cell Receptor Alpha Constant) is a protein coding gene located on chromosome 14q11.2.
General informationThis section has been translated automatically.
T cell receptors recognize foreign antigens processed as small peptides and bound to molecules of the major histocompatibility complex (MHC) on the surface of antigen-presenting cells (APCs). Each T cell receptor is a dimer consisting of an alpha and a beta chain or a delta and a gamma chain. In a single cell, the T cell receptor loci are rearranged and expressed in the order delta, gamma, beta, and alpha.
If both the delta and gamma rearrangements produce functional chains, the cell expresses delta and gamma. If they do not, the cell proceeds to rearrange the beta and alpha loci. This region represents the germline organization of the alpha and delta loci of the T cell receptor. Both the alpha and delta loci include V (variable), J (connecting), and C (constant) segments. The delta locus also includes diversity (D) segments located within the alpha locus, between the alpha V and J segments.
During T cell development, the delta chain is synthesized by a DNA-level recombination event in which a D segment is joined to a J segment; subsequently, a V segment is joined to the D-J gene. The alpha chain is synthesized by recombination of a single V segment with a J segment.
Five variable segments can be used in both the alpha and delta chains. Multiple V and J segments of the alpha locus are known to be incapable of encoding a protein and are considered pseudogenes.
Clinical pictureThis section has been translated automatically.
Diseases associated with TRAC include:
- Autosomal recessively inherited immunodeficiency 7 (Omim: 615387).
This involves an autosomal recessively inherited mutation in the TRAC gene, resulting in an absence of the T cell receptor-alpha chain. All CD3 T cells carry TZRgamma/delta, and T cell proliferation is impaired.
LiteratureThis section has been translated automatically.
- Morgan N V et al (2011) Mutation in the TCR-alpha subunit constant gene (TRAC) leads to a human immunodeficiency disorder characterized by a lack of TCR-alpha/beta+ T cells. J Clin Invest 121: 695-702.
- Rawat A et al.(2021) Skewed TCR alpha, but not beta, gene rearrangements and lymphoma associated with a pathogenic TRAC variant. J Clin Immun 41: 1395-1399.
