Harris P V, Mazina O M, Leonhardt E A, Case R B, Boyd J B, Burtis K C
Section of Molecular and Cellular Biology, University of California, Davis 95616, USA.
Mol Cell Biol. 1996 Oct;16(10):5764-71. doi: 10.1128/MCB.16.10.5764.
Mutations in the Drosophila mus308 gene confer specific hypersensitivity to DNA-cross-linking agents as a consequence of defects in DNA repair. The mus308 gene is shown here to encode a 229-kDa protein in which the amino-terminal domain contains the seven conserved motifs characteristic of DNA and RNA helicases and the carboxy-terminal domain shares over 55% sequence similarity with the polymerase domains of prokaryotic DNA polymerase I-like enzymes. This is the first reported member of this family of DNA polymerases in a eukaryotic organism, as well as the first example of a single polypeptide with homology to both DNA polymerase and helicase motifs. Identification of a closely related gene in the genome of Caenorhabditis elegans suggests that this novel polypeptide may play an evolutionarily conserved role in the repair of DNA damage in eukaryotic organisms.
果蝇mus308基因发生突变会因DNA修复缺陷而对DNA交联剂产生特定的超敏反应。本文显示，mus308基因编码一种229 kDa的蛋白质，其氨基末端结构域包含DNA和RNA解旋酶特有的七个保守基序，羧基末端结构域与原核DNA聚合酶I类酶的聚合酶结构域具有超过55%的序列相似性。这是真核生物中该DNA聚合酶家族首个被报道的成员，也是首个与DNA聚合酶和解旋酶基序都具有同源性的单一多肽实例。在秀丽隐杆线虫基因组中鉴定出一个密切相关的基因，这表明这种新型多肽可能在真核生物DNA损伤修复中发挥进化上保守的作用。
