CRISPR 相关转座子同源的双重模式。
Dual modes of CRISPR-associated transposon homing.
机构信息
Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; McGovern Institute for Brain Research at MIT, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; McGovern Institute for Brain Research at MIT, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
出版信息
Cell. 2021 Apr 29;184(9):2441-2453.e18. doi: 10.1016/j.cell.2021.03.006. Epub 2021 Mar 25.
Tn7-like transposons have co-opted CRISPR systems, including class 1 type I-F, I-B, and class 2 type V-K. Intriguingly, although these CRISPR-associated transposases (CASTs) undergo robust CRISPR RNA (crRNA)-guided transposition, they are almost never found in sites targeted by the crRNAs encoded by the cognate CRISPR array. To understand this paradox, we investigated CAST V-K and I-B systems and found two distinct modes of transposition: (1) crRNA-guided transposition and (2) CRISPR array-independent homing. We show distinct CAST systems utilize different molecular mechanisms to target their homing site. Type V-K CAST systems use a short, delocalized crRNA for RNA-guided homing, whereas type I-B CAST systems, which contain two distinct target selector proteins, use TniQ for RNA-guided DNA transposition and TnsD for homing to an attachment site. These observations illuminate a key step in the life cycle of CAST systems and highlight the diversity of molecular mechanisms mediating transposon homing.
Tn7 样转座子已经篡夺了 CRISPR 系统，包括 I 型 F、I 型 B 和 II 型 V-K。有趣的是，尽管这些 CRISPR 相关转座酶 (CASTs) 经历了强大的 CRISPR RNA (crRNA) 引导的转座，但它们几乎从未在由同源 CRISPR 阵列编码的 crRNA 靶向的位点中发现。为了理解这一悖论，我们研究了 CAST V-K 和 I-B 系统，发现了两种不同的转座方式：（1）crRNA 引导的转座和（2）CRISPR 阵列非依赖性归巢。我们展示了不同的 CAST 系统利用不同的分子机制来靶向它们的归巢位点。V-K 型 CAST 系统使用短的、非定位的 crRNA 进行 RNA 引导的归巢，而含有两个不同的靶标选择蛋白的 I-B 型 CAST 系统则使用 TniQ 进行 RNA 引导的 DNA 转座和 TnsD 归巢到附着位点。这些观察结果阐明了 CAST 系统生命周期中的一个关键步骤，并强调了介导转座子归巢的分子机制的多样性。
Zotero 插件