Skoko Dunja, Li Min, Huang Ying, Mizuuchi Michiyo, Cai Mengli, Bradley Christina M, Pease Paul J, Xiao Botao, Marko John F, Craigie Robert, Mizuuchi Kiyoshi
Laboratory of Molecular Biology, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Proc Natl Acad Sci U S A. 2009 Sep 29;106(39):16610-5. doi: 10.1073/pnas.0909077106. Epub 2009 Sep 21.
Barrier-to-autointegration factor (BAF) is a protein that has been proposed to compact retroviral DNA, making it inaccessible as a target for self-destructive integration into itself (autointegration). BAF also plays an important role in nuclear organization. We studied the mechanism of DNA condensation by BAF using total internal reflection fluorescence microscopy. We found that BAF compacts DNA by a looping mechanism. Dissociation of BAF from DNA occurs with multiphasic kinetics; an initial fast phase is followed by a much slower dissociation phase. The mechanistic basis of the broad timescale of dissociation is discussed. This behavior mimics the dissociation of BAF from retroviral DNA within preintegration complexes as monitored by functional assays. Thus the DNA binding properties of BAF may alone be sufficient to account for its association with the preintegration complex.
自身整合屏障因子（BAF）是一种蛋白质，有人提出它可使逆转录病毒DNA压缩，使其无法作为自我破坏性整合（自身整合）的靶点。BAF在细胞核组织中也起着重要作用。我们使用全内反射荧光显微镜研究了BAF使DNA凝聚的机制。我们发现BAF通过环化机制使DNA压缩。BAF从DNA上解离呈现多相动力学；初始的快速阶段之后是一个慢得多的解离阶段。讨论了解离时间尺度宽泛的机制基础。这种行为模拟了功能测定所监测的BAF从整合前复合物中的逆转录病毒DNA上的解离。因此，BAF的DNA结合特性可能单独就足以解释其与整合前复合物的关联。
