The Tn7 transposition regulator TnsC interacts with the transposase subunit TnsB and target selector TnsD
The Tn7 transposition regulator TnsC interacts with the transposase subunit TnsB and target selector TnsD
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DOI：
10.1073/pnas.1409869111
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发表时间：
2014-07-15
影响因子：
11.1
通讯作者：
Craig, Nancy L.
中科院分区：
文献类型：
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作者：
Choi, Ki Young;Spencer, Jeanelle M.;Craig, Nancy L.
转座子 Tn7 从供体位点切除并将其插入其首选靶位点（附着位点 attTn7）是由四种 Tn7 编码的转座蛋白介导的：TnsA、TnsB、TnsC 和 TnsD。转座需要组装包含所有四种 Tns 蛋白和 DNA 底物的核蛋白复合物、包含 Tn7 的供体位点和首选靶位点 attTn7。 TnsA 和 TnsB 一起形成异聚 Tn7 转座酶，TnsD 是一种与 attTn7 特异性结合的靶标选择蛋白。 TnsC 是转座的关键调节因子，与 TnsAB 转座酶和 TnsD-attTn7 相互作用。我们在这里展示了 TnsC 直接与 TnsB 相互作用，并确定了转座过程中参与 TnsB-TnsC 相互作用的 TnsC 特定区域。我们还表明，与 TnsB 相互作用有缺陷的 TnsC 突变体在体外和体内都有 Tn7 转座缺陷。 Tn7 表现出顺式作用靶标免疫，阻止 Tn7 插入已含有 Tn7 的靶标 DNA 中。我们提供的证据表明，我们已经确定的直接 TnsB-TnsC 相互作用也介导顺式作用 Tn7 靶点免疫。我们还表明 TnsC 直接与靶选择蛋白 TnsD 相互作用。
The excision of transposon Tn7 from a donor site and its insertion into its preferred target site, attachment site attTn7, is mediated by four Tn7-encoded transposition proteins: TnsA, TnsB, TnsC, and TnsD. Transposition requires the assembly of a nucleoprotein complex containing all four Tns proteins and the DNA substrates, the donor site containing Tn7, and the preferred target site attTn7. TnsA and TnsB together form the heteromeric Tn7 transposase, and TnsD is a target-selecting protein that binds specifically to attTn7. TnsC is the key regulator of transposition, interacting with both the TnsAB transposase and TnsD-attTn7. We show here that TnsC interacts directly with TnsB, and identify the specific region of TnsC involved in the TnsB-TnsC interaction during transposition. We also show that a TnsC mutant defective in interaction with TnsB is defective for Tn7 transposition both in vitro and in vivo. Tn7 displays cis-acting target immunity, which blocks Tn7 insertion into a target DNA that already contains Tn7. We provide evidence that the direct TnsB-TnsC interaction that we have identified also mediates cis-acting Tn7 target immunity. We also show that TnsC interacts directly with the target selector protein TnsD.