title: No functional gamma-chain transcripts detected in an alloreactive cytotoxic T-cell clone.
abstract: Three groups of genes that undergo rearrangements during T-cell maturation have been isolated from T cells. Two of them encode the alpha- and beta-subunits of the T-cell antigen receptor and are shared between antigen-specific, major histocompatibility (MHC) class I-restricted cytotoxic T cells and antigen-specific, MHC class II-restricted helper T cells. The third group of genes, called gamma, is preferentially transcribed in cytotoxic T cells. This led to the hypothesis that the unidentified gamma-gene products could be part of a putative T-cell receptor responsible for MHC class I recognition. We report here on the isolation of three different types of gamma-gene transcripts of an alloreactive cytotoxic T-cell clone (3F9). Two are derived from two rearrangements that have occurred at the same locus (V gamma 10.8A to J gamma 10.5 and transcribed with C gamma 10.5), while the third involves a new V gamma-gene segment that is joined to J gamma 13.4 and transcribed with C gamma 13.4. All these rearrangements are abortive and lead to the formation of non-functional gamma-chain genes because the proper translational reading frame is not maintained. Because the second copy of the C gamma 13.4 gene segment is deleted and as C gamma 7.5 is considered to be a pseudogene and has not undergone any rearrangements in 3F9, we conclude that the alloreactive cytotoxic T-cell clone 3F9 does not contain a functional transcript of a known gamma-chain gene.
mesh_terms: D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D002999:Clone Cells; D004247:DNA / Q000032:analysis; D004262:DNA Restriction Enzymes / Q000378:metabolism; D005796:Genes; D008285:Major Histocompatibility Complex; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D011948:Receptors, Antigen, T-Cell / Q000235:genetics*; D013602:T-Lymphocytes, Cytotoxic / Q000032:analysis*; D014158:Transcription, Genetic
chemical_list: D011948:Receptors, Antigen, T-Cell; D004247:DNA; D004262:DNA Restriction Enzymes