Feldmann H, Driller L, Meier B, Mages G, Kellermann J, Winnacker E L
Institut für Biochemie der Universität München, Feodor-Lynen-Str. 25, 81377 München, Federal Republic of Germany.
J Biol Chem. 1996 Nov 1;271(44):27765-9. doi: 10.1074/jbc.271.44.27765.
The high affinity DNA binding factor (HDF) protein of Saccharomyces cerevisiae is composed of two subunits and specifically binds ends of double-stranded DNA. The 70-kDa subunit, HDF1, shows significant homology with the 70-kDa subunit of the human Ku protein. Like the Ku protein, HDF1 has been shown to be involved in recombination and double stranded DNA break repair. We have purified and cloned HDF2, the second subunit of the HDF protein. The amino acid sequence of HDF2 shows a 45.6% homology with the 80-kDa subunit of the Ku protein. HDF1 by itself does not bind DNA, while HDF2 protein on its own seems to displays DNA binding activity. Targeted disruption of the HDF2 gene causes a temperature-sensitive phenotype for growth comparable to the phenotype of hdf1(-) strains. The human Ku protein cannot complement this temperature-sensitive phenotype. hdf2(-) strains are sensitive to bleomycin and methyl methanesulfonate, but this sensitivity is reduced in comparison with hdf1(-) strains.
酿酒酵母的高亲和力DNA结合因子（HDF）蛋白由两个亚基组成，并特异性结合双链DNA的末端。70 kDa亚基HDF1与人Ku蛋白的70 kDa亚基具有显著同源性。与Ku蛋白一样，HDF1已被证明参与重组和双链DNA断裂修复。我们已经纯化并克隆了HDF蛋白的第二个亚基HDF2。HDF2的氨基酸序列与Ku蛋白的80 kDa亚基具有45.6%的同源性。HDF1自身不结合DNA，而HDF2蛋白自身似乎具有DNA结合活性。靶向破坏HDF2基因会导致与hdf1（-）菌株表型相当的生长温度敏感表型。人Ku蛋白不能弥补这种温度敏感表型。hdf2（-）菌株对博来霉素和甲基磺酸甲酯敏感，但与hdf1（-）菌株相比，这种敏感性有所降低。
