HIV-1 integrase forms stable tetramers and associates with LEDGF/p75 protein in human cells
HIV-1 integrase forms stable tetramers and associates with LEDGF/p75 protein in human cells
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DOI：
10.1074/jbc.m209278200
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发表时间：
2003-01-03
影响因子：
4.8
通讯作者：
Debyser, Z
中科院分区：
文献类型：
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作者：
Cherepanov, P;Maertens, G;Debyser, Z
我们研究了人类免疫缺陷病毒，1型（HIV-1）整合酶（IN）复合物来源于稳定表达来自合成基因的病毒蛋白的人细胞核。我们表明，在核提取物中，IN作为具有61埃的表观斯托克斯半径的大的不同复合物的一部分存在，其在稀释时解离，产生41埃的核心分子。我们从表达FLAG标记的IN的细胞中分离出IN复合物，并证明41埃核心是IN的四聚体，而61埃分子由与表观分子量为76 kDa的细胞蛋白相关的IN四聚体组成。发现这种新的整合酶相互作用蛋白与透镜上皮衍生生长因子（LEDGF/p75）相同，LEDGF/p75是一种涉及基因表达和细胞应激反应调节的蛋白。HIV-1 IN和LEDGF共定位于稳定表达IN的人细胞的细胞核中。此外，重组LEDGF在体外强烈增强HIV-1 IN的链转移活性。我们的研究结果表明，人类细胞中的最小IN分子是一个同源四聚体，这表明至少需要一个八聚体的IN来完成两个逆转录病毒长末端重复序列的协调整合，LEDGF是参与这一过程的细胞因子。
We studied human immunodeficiency virus, type 1 (HIV-1) integrase (IN) complexes derived from nuclei of human cells stably expressing the viral protein from a synthetic gene. We show that in the nuclear extracts IN exists as part of a large distinct complex with an apparent Stokes radius of 61 Angstrom, which dissociates upon dilution yielding a core molecule of 41 Angstrom. We isolated the IN complexes from cells expressing FLAG-tagged IN and demonstrated that the 41 Angstrom core is a tetramer of IN, whereas 61 Angstrom molecules are composed of IN tetramers associated with a cellular protein with an apparent molecular mass of 76 kDa. This novel integrase interacting protein was found to be identical to lens epithelium-derived growth factor (LEDGF/p75), a protein implicated in regulation of gene expression and cellular stress response. HIV-1 IN and LEDGF co-localized in the nuclei of human cells stably expressing IN. Furthermore, recombinant LEDGF robustly enhanced strand transfer activity of HIV-1 IN in vitro. Our findings indicate that the minimal IN molecule in human cells is a homotetramer, suggesting that at least an octamer of IN is required to accomplish coordinated integration of both retroviral long terminal repeats and that LEDGF is a cellular factor involved in this process.