Circular Excision Products Generated by T-cell Receptor Gene Rearrangements

我们在胎儿和成年小鼠胸腺细胞和脾细胞中克隆了含有T细胞受体（TCR） delta、gamma和bata基因片段的染色体外环状dna。结果发现：(1)Vdelta基因vdelta7、Vdelta8和Vdelta9为新基因；(2) Jdelta2在胸腺细胞中使用，而在脾细胞中不使用；(3)与人类delta基因删除元件deltaRec1、deltaRec2和deltaRec3同源的新序列，以及位于Jalpha- calpha内含子上游的Jalpha假基因（PSIJalpha）；(4)两个Ddelta元的倒数连接；(5) Vgamma5和Vgamma6在胎儿晚期胸腺细胞中优先使用，Vgamma4和Vgamma7在胎儿晚期和成人胸腺细胞中普遍使用；(6)优先使用c2相关γ基因；(7) TCR - α重排环形切除产物；(8)非遗传元素(N)在成年胸腺细胞中γ、δ和β信号关节的插入频率高（70%），δ和β信号关节的插入频率高（25%），而在胎儿胸腺细胞中没有插入；(9) t细胞早期α (TEA)转录本拼接到Calpha上；（10） TEA-Calpha在胎期17天表达量最大；（11）在α - t细胞系EL-4中，位于TEA转录起始位点上游2.4 kb的沉默区。

We have cloned extrachromosomal circular DNAs containing T Cell Receptor (TCR) delta, gamma and bata gene segments in fetal and adult mouse thymocytes and splenocytes. We found that : (1) New Vdelta genes, vdelta7, Vdelta8 and Vdelta9 ; (2) Jdelta2 usage in thymocytes but not in splenocytes ; (3) Novel sequences homologous to human delta-gene deleting elements, deltaRec1, deltaRec2 and deltaRec3, and a pseudogene of Jalpha (PSIJalpha) lying upstream of the Jalpha-Calpha intron ; (4) Reciprocal joining of two Ddelta elements ; (5) Preferential usage of Vgamma5 and Vgamma6 in late fetal thymocytes and general usage of Vgamma4 and Vgamma7 in both late fetal and adult thymocytes ; (6) Preferential usage of C2-associated gamma gene ; (7) Circular excision products by TCR gamma-alpha transrearrangements ; (8) High frequency of nongermline element (N) insertions into signal joints of gamma (70%), delta (25%) and beta (20%) in adult thymocytes but no insertions in fetal thymocytes ; (9) T-cell early alpha (TEA) transcripts spliced to Calpha ; (10) Maximum expression of TEA-Calpha at fetal stage of 17 days ; (11) Silencer region 2.4 kb upstream from a initiation site of TEA transcription functioning in alphabeta T-cell line, EL-4.