title: Regulation of N-region diversity in antigen receptors through thymocyte differentiation and thymus ontogeny.
abstract: The random addition of "N nucleotides" by terminal deoxynucleotidyltransferase (TdT) is an important component of the diversity of T-cell receptor genes. We have investigated the expression of TdT during thymocyte differentiation and thymus ontogeny. TdT gene transcripts are confined to immature thymocytes of the cortex, being down-regulated concomitantly with recombination-activating gene transcripts after positive selection of mature medullary T cells. According to in situ hybridization, TdT RNA is absent from the neonatal thymus, but it appears 3 to 5 days after birth, just before the appearance of significant N-region diversity in T-cell receptor junctional sequences but clearly after the thymus attains competence at clonal deletion.
authors.affiliation: Laboratoire de Génétique Moléculaire des Eucaryotes, Centre National de la Recherche Scientifique, Strasbourg, France.
authors.forename: M
authors.initials: M
authors.lastname: Bogue
authors.forename: S
authors.initials: S
authors.lastname: Gilfillan
authors.forename: C
authors.initials: C
authors.lastname: Benoist
authors.forename: D
authors.initials: D
authors.lastname: Mathis
mesh_terms: D000375:Aging / Q000276:immunology / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D002454:Cell Differentiation; D004253:DNA Nucleotidylexotransferase / Q000235:genetics; D005091:Exons; D005786:Gene Expression Regulation; D014644:Genetic Variation; D006321:Heart / Q000254:growth & development*; D018398:Homeodomain Proteins; D051379:Mice; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D016133:Polymerase Chain Reaction / Q000379:methods; D011506:Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D011948:Receptors, Antigen, T-Cell / Q000235:genetics*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D013950:Thymus Gland / Q000254:growth & development* / Q000276:immunology*; D014158:Transcription, Genetic
chemical_list: D018398:Homeodomain Proteins; D009838:Oligodeoxyribonucleotides; D011506:Proteins; D012333:RNA, Messenger; D011948:Receptors, Antigen, T-Cell; C064658:RAG-1 protein; D004253:DNA Nucleotidylexotransferase