Two Arabidopsis Loci Encode Novel Eukaryotic Initiation Factor 4E Isoforms That Are Functionally Distinct from the Conserved Plant Eukaryotic Initiation Factor 4E1[W][OPEN]
Two Arabidopsis Loci Encode Novel Eukaryotic Initiation Factor 4E Isoforms That Are Functionally Distinct from the Conserved Plant Eukaryotic Initiation Factor 4E1[W][OPEN]
复制标题
两个拟南芥基因座编码新的真核起始因子 4E 亚型，其功能不同于保守的植物真核起始因子 4E1[W][OPEN]
作者：
R. M. Patrick;Laura K. Mayberry;Grace S. Choy;L. Woodard;Joceline S. Liu;A. White;Rebecca A Mullen;Toug Tanavin;Christopher A Latz;K. Browning
十字花科特异的 RNA 帽结合蛋白的不同形式不会与保守形式竞争翻译起始。真核生物中的规范翻译起始始于真核起始因子 4F (eIF4F) 复合物，该复合物由 eIF4E 和 eIF4G 组成，其中 eIF4E 识别信使 RNA 的 7-甲基鸟苷帽，而 eIF4G 充当招募其他翻译起始因子的支架，最终组装 80S 核糖体。许多真核生物具有具有不同特性的次级 EIF4E 基因。模型植物拟南芥 (Arabidopsis thaliana) 在 1 号染色体上的串联基因座中编码两个这样的基因：EIF4E1B (At1g29550) 和 EIF4E1C (At1g29590)。这项工作将 EIF4E1B/EIF4E1C 型基因鉴定为十字花科特异性 EIF4E 的分化形式。 EIF4E1C 基因表达的证据很少；然而，尽管微阵列和RNA测序数据支持生殖组织中EIF4E1B基因的富集，但EIF4E1B基因似乎在大多数组织中以低水平表达。纯化的重组 eIF4E1b 和 eIF4E1c 蛋白保留帽结合能力，并在体外与 eIF4G 形成功能复合物。 eIF4E1b/eIF4E1c 型蛋白支持酵母（酿酒酵母）中的翻译，但与 eIF4E 相比，在体外以较低的速率促进翻译起始。表面等离子共振研究结果表明，eIF4E1b 和 eIF4E1c 在与 eIF4E 竞争时不太可能在体内结合 eIF4G。本研究得出的结论是，eIF4E1b/eIF4E1c 型蛋白虽然是真正的帽结合蛋白，但具有不同的特性，并且基于拟南芥中明显有限的组织分布，应被认为在功能上不同于参与翻译起始的典型植物 eIF4E。
Brassicaceae-specific divergent forms of RNA cap-binding proteins do not compete with the conserved form in translation initiation. Canonical translation initiation in eukaryotes begins with the Eukaryotic Initiation Factor 4F (eIF4F) complex, made up of eIF4E, which recognizes the 7-methylguanosine cap of messenger RNA, and eIF4G, which serves as a scaffold to recruit other translation initiation factors that ultimately assemble the 80S ribosome. Many eukaryotes have secondary EIF4E genes with divergent properties. The model plant Arabidopsis (Arabidopsis thaliana) encodes two such genes in tandem loci on chromosome 1, EIF4E1B (At1g29550) and EIF4E1C (At1g29590). This work identifies EIF4E1B/EIF4E1C-type genes as a Brassicaceae-specific diverged form of EIF4E. There is little evidence for EIF4E1C gene expression; however, the EIF4E1B gene appears to be expressed at low levels in most tissues, though microarray and RNA Sequencing data support enrichment in reproductive tissue. Purified recombinant eIF4E1b and eIF4E1c proteins retain cap-binding ability and form functional complexes in vitro with eIF4G. The eIF4E1b/eIF4E1c-type proteins support translation in yeast (Saccharomyces cerevisiae) but promote translation initiation in vitro at a lower rate compared with eIF4E. Findings from surface plasmon resonance studies indicate that eIF4E1b and eIF4E1c are unlikely to bind eIF4G in vivo when in competition with eIF4E. This study concludes that eIF4E1b/eIF4E1c-type proteins, although bona fide cap-binding proteins, have divergent properties and, based on apparent limited tissue distribution in Arabidopsis, should be considered functionally distinct from the canonical plant eIF4E involved in translation initiation.
影响因子：
3.5
作者：
HORTON, RM;HUNT, HD;PEASE, LR
通讯作者：
PEASE, LR
影响因子：
4.1
作者：
Coldwell, Mark J.;Sack, Ulrike;Morley, Simon J.
通讯作者：
Morley, Simon J.