DNTT（DNA nucleotidylexotransferase），癌症关联基因，基因ID：1791，该基因是DNA聚合酶X型家族的一员，编码一种对寡核苷酸引物的3'-羟基末端添加脱氧核苷酸进行催化的模板无关DNA聚合酶在体内，编码蛋白在正常和恶性的前b和前t淋巴细胞的限制性群体中在早期分化过程中表达，通过在重组ig重链和t细胞受体基因片段的连接处合成非生殖系元素（n区）来产生抗原受体多样性。另外，还描述了编码该基因不同亚型的剪接转录变体[由RefSeq提供，2008年7月]This gene is a member of the DNA polymerase type-X family and encodes a template-independent DNA polymerase that catalyzes the addition of deoxynucleotides to the 3'-hydroxyl terminus of oligonucleotide primers. In vivo， the encoded protein is expressed in a restricted population of normal and malignant pre-B and pre-T lymphocytes during early differentiation， where it generates antigen receptor diversity by synthesizing non-germ line elements (N-regions) at the junctions of rearranged Ig heavy chain and T cell receptor gene segments. Alternatively spliced transcript variants encoding different isoforms of this gene have been described. [provided by RefSeq， Jul 2008]。