Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland.
Molecules. 2019 Jul 31;24(15):2789. doi: 10.3390/molecules24152789.
Arabidopsis roots accumulate a complex mixture of dolichols composed of three families, (i.e., short-, medium- and long-chain dolichols), but until now none of the -prenyltransferases (CPTs) predicted in the Arabidopsis genome has been considered responsible for their synthesis. In this report, using homo- and heterologous (yeast and tobacco) models, we have characterized the gene (At2g23410) which encodes a CPT responsible for the formation of long-chain dolichols, Dol-18 to -23, with Dol-21 dominating, in Arabidopsis. The content of these dolichols was significantly reduced in T-DNA insertion mutant lines and highly increased in -overexpressing plants. Similar to the majority of eukaryotic CPTs, AtCPT1 is localized to the endoplasmic reticulum (ER). Functional complementation tests using yeast Δ or Δ mutants devoid of medium- or long-chain dolichols, respectively, confirmed that this enzyme synthesizes long-chain dolichols, although the dolichol chains thus formed are somewhat shorter than those synthesized in planta. Moreover, AtCPT1 acts as a homomeric CPT and does not need LEW1 for its activity. AtCPT1 is the first plant CPT producing long-chain polyisoprenoids that does not form a complex with the NgBR/NUS1 homologue.
拟南芥根积累了由三种家族组成的复杂混合物（即短链、中链和长链），但到目前为止，拟南芥基因组中预测的任何一种 -prenyltransferase（CPT）都没有被认为负责其合成。在本报告中，我们使用同源和异源（酵母和烟草）模型，鉴定了编码负责长链 Dolichols（Dol-18 至 -23，以 Dol-21 为主）合成的 CPT 的基因（At2g23410）。在 T-DNA 插入突变体系中，这些 Dolichols 的含量显著降低，而过表达植物中的含量则显著增加。与大多数真核 CPT 一样，AtCPT1 定位于内质网（ER）。使用酵母 Δ或 Δ突变体的功能互补测试，这些突变体分别缺乏中链或长链 Dolichols，证实了该酶合成长链 Dolichols，尽管由此形成的 Dolichol 链比在植物中合成的稍短。此外，AtCPT1 作为一种同型 CPT，其活性不需要 LEW1。AtCPT1 是第一个产生长链多异戊二烯的植物 CPT，它不与 NgBR/NUS1 同源物形成复合物。
