Kung P C, Siverstone A E, McCaffrey R P, Baltimore D
J Exp Med. 1975 Apr 1;141(4):855-65.
The mouse thymus contains two forms of terminal deoxynucleotidyl transferase (TdT) which are distinguishable by the salt concentration necessary to elute them from a phosphocellulose column, by their distrubtion among the thymocyte subpopulations, and by their sensitivity to cortisone treatment. In the whole thymus the later eluting peak (peak II) is the predominant one with about 3-10% of the total activity appearing in peak I. Both peak I and peak II activities are most sensitively assayed by the polymerization of dGMP onto an oligo(dA) primer. The minor population of thymocytes which is less dense and cortisone-resistant contains a higher specific activity of peak I TdT. The majority of TdT activity is, however, found in the major population of thymocytes which occurs in the center region of a bovine serum albumin gradient and is cortisone-sensitive. A very low level of an activity indistinguishable from peak II TdT activity is also detected in the mouse bone marrow. Other tissues, such as spleen, liver, heart, and brain lack detectable amounts of TdT activity.
小鼠胸腺含有两种形式的末端脱氧核苷酸转移酶（TdT），可通过从磷酸纤维素柱上洗脱它们所需的盐浓度、它们在胸腺细胞亚群中的分布以及它们对可的松处理的敏感性来区分。在整个胸腺中，较晚洗脱的峰（峰II）是主要的峰，约3-10%的总活性出现在峰I中。峰I和峰II的活性通过将dGMP聚合到寡聚（dA）引物上进行最灵敏的测定。密度较小且对可的松有抗性的少数胸腺细胞群体含有较高比活性的峰I TdT。然而，大多数TdT活性存在于牛血清白蛋白梯度中心区域出现的主要胸腺细胞群体中，且对可的松敏感。在小鼠骨髓中也检测到极低水平的与峰II TdT活性无法区分的活性。其他组织，如脾脏、肝脏、心脏和大脑，缺乏可检测到的TdT活性。
