Nakajima P B, Menetski J P, Roth D B, Gellert M, Bosma M J
Institute for Cancer Research Fox Chase Cancer Center Philadelphia, Pennsylvania 19111, USA.
Immunity. 1995 Nov;3(5):609-21. doi: 10.1016/1074-7613(95)90132-9.
The T cell receptor (TCR) delta locus lies within the TCR alpha locus and is excised from the chromosome by V alpha-J alpha rearrangement. We show here that delta sequences persist in a large fraction of the DNA from mature CD4+CD8- alpha beta+ mouse thymocytes. Virtually all delta loci in these cells are rearranged and present in extrachromosomal DNA. In immature alpha beta lineage thymocytes (CD3-/loCD4+CD8+) and in CD4+CD8- alpha beta+ thymocytes expressing a transgene-encoded alpha beta receptor, rearranged delta genes are present both in chromosomal and extrachromosomal DNA. Thus, contrary to earlier proposals, commitment to the alpha beta lineage does not require recombinational silencing of the delta locus or its deletion by a site-specific mechanism prior to V alpha-J alpha rearrangement.
T细胞受体（TCR）δ基因座位于TCRα基因座内，并通过Vα-Jα重排从染色体上切除。我们在此表明，δ序列在成熟CD4⁺CD8⁻αβ⁺小鼠胸腺细胞的大部分DNA中持续存在。这些细胞中几乎所有的δ基因座都发生了重排，并存在于染色体外DNA中。在未成熟的αβ谱系胸腺细胞（CD3⁻/低CD4⁺CD8⁺）和表达转基因编码的αβ受体的CD4⁺CD8⁻αβ⁺胸腺细胞中，重排的δ基因既存在于染色体DNA中，也存在于染色体外DNA中。因此，与早期的观点相反，向αβ谱系的定向分化并不需要在Vα-Jα重排之前通过位点特异性机制对δ基因座进行重组沉默或删除。
