Sutherland B M, Bennett P V
Biology Department, Brookhaven National Laboratory, Upton, NY 11973-5000, USA.
Proc Natl Acad Sci U S A. 1995 Oct 10;92(21):9732-6. doi: 10.1073/pnas.92.21.9732.
Although enzymatic photoreactivation of cyclobutyl pyrimidine dimers in DNA is present in almost all organisms, its presence in placental mammals is controversial. We tested human white blood cells for photolyase by using three defined DNAs (supercoiled pET-2, nonsupercoiled bacteriophage lambda, and a defined-sequence 287-bp oligonucleotide), two dimer-specific endonucleases (T4 endonuclease V and UV endonuclease from Micrococcus luteus), and three assay methods. We show that human white blood cells contain photolyase that can photorepair pyrimidine dimers in defined supercoiled and linear DNAs and in a 287-bp oligonucleotide and that human photolyase is active on genomic DNA in intact human cells.
尽管DNA中环丁基嘧啶二聚体的酶促光复活作用几乎存在于所有生物体中，但在胎盘哺乳动物体内是否存在一直存在争议。我们使用三种特定的DNA（超螺旋pET-2、非超螺旋噬菌体λ和一段287碱基对的特定序列寡核苷酸）、两种二聚体特异性核酸内切酶（T4核酸内切酶V和藤黄微球菌紫外线核酸内切酶）以及三种检测方法，对人类白细胞进行了光解酶检测。我们发现，人类白细胞含有光解酶，该酶能够对特定的超螺旋和线性DNA以及一段287碱基对的寡核苷酸中的嘧啶二聚体进行光修复，并且人类光解酶在完整的人类细胞中的基因组DNA上具有活性。
