Structure of a Ty1 restriction factor reveals the molecular basis of transposition copy number control.
Structure of a Ty1 restriction factor reveals the molecular basis of transposition copy number control.
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DOI：
10.1038/s41467-021-25849-0
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发表时间：
2021-09-22
影响因子：
16.6
通讯作者：
Taylor IA
中科院分区：
文献类型：
--
作者：
Cottee MA;Beckwith SL;Letham SC;Kim SJ;Young GR;Stoye JP;Garfinkel DJ;Taylor IA
酿酒酵母Ty1逆转录转座子的过度复制受拷贝数控制的调控，这一过程需要从Ty1 GAG内起始的亚基因组转录物产生p22/p18蛋白。在逆转录转座中，Gag执行复制和重新整合所需的衣壳功能。为了使基因组损伤最小化，p22/p18通过与Gag相互作用中断病毒样颗粒功能。在这里，我们提出了结构，生物物理和遗传分析的p18 m，最小的片段的加格，限制转座。p18m的2.8 nm晶体结构揭示了一种与哺乳动物和昆虫ARC蛋白相关的全α螺旋蛋白。P18M保留了在溶液中二聚化的能力，并且晶体结构揭示了两个排他的二聚体界面。我们探测我们的研究结果，通过生物物理分析的接口突变体，以及Ty1转座和p18 m限制在体内。我们的数据提供了对Ty1 Gag结构的深入了解，并表明p22/p18可能如何通过阻止组装机制在限制中发挥作用。在酿酒酵母中，Ty1反转录转座子的不受抑制的增殖是由拷贝数控制（CNC）过程控制的，这需要从Ty1 GAG基因内的内部转录物翻译的p22/p18蛋白。在这里，作者提出了Ty1-Gag的最小p18的2.8 μ m晶体结构，该结构能够限制Ty1转座并确定p18中的两个二聚体界面，其作用通过体外和体内诱变来探测。由于p22/p18仅包含逆转录元件Gag组装所需的两个保守结构域之一，他们提出p22/p18-Gag相互作用阻断了Ty1病毒样颗粒组装途径，导致缺陷颗粒无法支持逆转录转座。
Excessive replication of Saccharomyces cerevisiae Ty1 retrotransposons is regulated by Copy Number Control, a process requiring the p22/p18 protein produced from a sub-genomic transcript initiated within Ty1 GAG. In retrotransposition, Gag performs the capsid functions required for replication and re-integration. To minimize genomic damage, p22/p18 interrupts virus-like particle function by interaction with Gag. Here, we present structural, biophysical and genetic analyses of p18m, a minimal fragment of Gag that restricts transposition. The 2.8 Å crystal structure of p18m reveals an all α-helical protein related to mammalian and insect ARC proteins. p18m retains the capacity to dimerise in solution and the crystal structures reveal two exclusive dimer interfaces. We probe our findings through biophysical analysis of interface mutants as well as Ty1 transposition and p18m restriction in vivo. Our data provide insight into Ty1 Gag structure and suggest how p22/p18 might function in restriction through a blocking-of-assembly mechanism. In Saccharomyces cerevisiae, unchecked proliferation of Ty1 retrotransposons is controlled by the process of copy number control (CNC), which requires the p22/p18 protein, translated from an internal transcript within the Ty1 GAG gene. Here, the authors present the 2.8 Å crystal structure of a minimal p18 from Ty1-Gag that is able to restrict Ty1 transposition and identify two dimer interfaces in p18, whose roles were probed by mutagenesis both in vitro and in vivo. As p22/p18 contains only one of two conserved domains required for retroelement Gag assembly, they propose that p22/p18-Gag interactions block the Ty1 virus-like particle assembly pathway, resulting in defective particles incapable of supporting retrotransposition.
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影响因子：
2.7
作者：
Chen VB;Wedell JR;Wenger RK;Ulrich EL;Markley JL
通讯作者：
Markley JL
影响因子：
64.5
作者：
Ashley J;Cordy B;Lucia D;Fradkin LG;Budnik V;Thomson T
通讯作者：
Thomson T
影响因子：
13.6
作者：
Cottee, Matthew A.;Letham, Suzanne C.;Taylor, Ian A.
通讯作者：
Taylor, Ian A.
影响因子：
4.8
作者：
Cristofari, G;Ficheux, D;Darlix, JL
通讯作者：
Darlix, JL
DOI：
10.1073/pnas.88.3.936
发表时间：
1991-02-01
影响因子：
11.1
作者：
CURCIO, MJ;GARFINKEL, DJ
通讯作者：
GARFINKEL, DJ