Kolodner R, Hall S D, Luisi-DeLuca C
Division of Cellular and Molecular Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115.
Mol Microbiol. 1994 Jan;11(1):23-30. doi: 10.1111/j.1365-2958.1994.tb00286.x.
Early genetic analysis of alternate recombination pathways in Escherichia coli identified the RecE recombination pathway and the required exonuclease VIII encoded by the recE gene. Observations that not all recombination events promoted by the RecE pathway require recA suggest the existence of an additional homologous pairing protein besides RecA in E. coli. Genetic and biochemical analysis of the recE gene region indicates there are two partially overlapping genes, recE and recT, encoding at least two proteins: exoVIII and the RecT protein. Biochemical analysis has shown that the RecT protein, in combination with exoVIII, promotes homologous pairing and strand exchange in reactions containing linear duplex DNA and homologous, circular, singlestranded DNA as substrates. This reaction occurs in the absence of any high-energy cofactor. These two proteins, RecT and exoVIII, appear to be members of a second class of homologous pairing proteins that are required in genetic recombination and differ from the class of homologous pairing proteins that includes RecA. Members of this second class of proteins appear to include both bacteriophage-encoded proteins and proteins from eukaryotes and their viruses.
对大肠杆菌中交替重组途径的早期遗传分析确定了RecE重组途径以及由recE基因编码的所需核酸外切酶VIII。并非所有由RecE途径促进的重组事件都需要recA，这一观察结果表明，除了RecA之外，大肠杆菌中还存在一种额外的同源配对蛋白。对recE基因区域的遗传和生化分析表明，有两个部分重叠的基因recE和recT，它们编码至少两种蛋白质：核酸外切酶VIII和RecT蛋白。生化分析表明，RecT蛋白与核酸外切酶VIII相结合，在以线性双链DNA和同源环状单链DNA为底物的反应中促进同源配对和链交换。该反应在没有任何高能辅因子的情况下发生。这两种蛋白质RecT和核酸外切酶VIII似乎是遗传重组中所需的第二类同源配对蛋白的成员，并且不同于包括RecA在内的同源配对蛋白类别。这第二类蛋白质的成员似乎包括噬菌体编码的蛋白质以及来自真核生物及其病毒的蛋白质。
