DNA polymerase θ (Pol θ) is a DNA repair enzyme widely conserved in animals and plants. Pol θ uses short DNA sequence homologies to initiate repair of double-strand breaks by theta-mediated end joining. The DNA polymerase domain of Pol θ is at the C terminus and is connected to an N-terminal DNA helicase–like domain by a central linker. Pol θ is crucial for maintenance of damaged genomes during development, protects DNA against extensive deletions, and limits loss of heterozygosity. The cost of using Pol θ for genome protection is that a few nucleotides are usually deleted or added at the repair site. Inactivation of Pol θ often enhances the sensitivity of cells to DNA strand–breaking chemicals and radiation. Since some homologous recombination–defective cancers depend on Pol θ for growth, inhibitors of Pol θ may be useful in treating such tumors.

中文翻译：

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DNA 聚合酶 θ 保护基因组

DNA聚合酶θ（Pol θ）是一种在动植物中广泛保守的DNA修复酶。 Pol θ 使用短 DNA 序列同源性通过 θ 介导的末端连接来启动双链断裂的修复。 Pol θ 的 DNA 聚合酶结构域位于 C 末端，并通过中央接头连接到 N 末端 DNA 解旋酶样结构域。 Pol θ 对于发育过程中受损基因组的维持至关重要，可以保护 DNA 免遭广泛缺失，并限制杂合性的损失。使用 Pol θ 进行基因组保护的成本是，通常会在修复位点删除或添加一些核苷酸。 Pol θ 的失活通常会增强细胞对 DNA 链断裂化学物质和辐射的敏感性。由于一些同源重组缺陷型癌症的生长依赖于 Pol θ，因此 Pol θ 抑制剂可能有助于治疗此类肿瘤。