Bogue M, Gilfillan S, Benoist C, Mathis D
Laboratoire de Génétique Moléculaire des Eucaryotes, Centre National de la Recherche Scientifique, Strasbourg, France.
Proc Natl Acad Sci U S A. 1992 Nov 15;89(22):11011-5. doi: 10.1073/pnas.89.22.11011.
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.
末端脱氧核苷酸转移酶（TdT）随机添加“N核苷酸”是T细胞受体基因多样性的一个重要组成部分。我们研究了TdT在胸腺细胞分化和胸腺个体发育过程中的表达。TdT基因转录本局限于皮质的未成熟胸腺细胞，在成熟髓质T细胞阳性选择后，与重组激活基因转录本同时下调。原位杂交显示，新生胸腺中不存在TdT RNA，但在出生后3至5天出现，就在T细胞受体连接序列中出现显著的N区多样性之前，但明显在胸腺获得克隆清除能力之后。
