Diversity of novel recombining elements suggests developmentally programmed expression of the T cell receptor alpha/delta locus.
During fetal ontogeny, the first wave of gamma delta T lymphocytes appears in the thymus at day 14 of gestation assembling predominantly T cell receptors (TcR) with V gamma 3 and V delta 1. To identify V delta gene segments that are transcribed at day 16, subsequent to the first wave of V delta 1 expression, delta chain cDNA was amplified by the anchored polymerase chain reaction with single-sided specificity for C delta. Unexpectedly, most of the cDNA clones do not contain V gene segments. In some cDNA clones an alternative splice from the leader exon to the C delta exon has deleted the whole variable region exon. In other cDNA clones, multiple non-V-like elements are juxtaposed to the D delta 2 and J delta 1 gene segments. A large number of these diverse elements appear to be rearranged in fetal thymocytes, bringing V alpha gene segments located upstream of the recombining element into proximity to the J alpha locus. It is proposed that these rearrangements make irreversible the commitment to the TcR alpha beta lineage and determine a programmed read out of different clusters of V alpha gene segments.
Arden
B
B
Max-Planck-Institut für Immunbiologie, Freiburg, FRG.
D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D004247:DNA / Q000032:analysis; D005091:Exons; D005260:Female; D005333:Fetus / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D011247:Pregnancy; D012326:RNA Splicing; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics*; D011995:Recombination, Genetic
D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta; D004247:DNA