PRH75, a new nucleus-localized member of the DEAD-box protein family from higher plants
PRH75, a new nucleus-localized member of the DEAD-box protein family from higher plants
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DOI：
10.1128/mcb.17.4.2257
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发表时间：
1997-04-01
影响因子：
5.3
通讯作者：
Oelmuller, R
中科院分区：
文献类型：
--
作者：
Lorkovic, ZJ;Herrmann, RG;Oelmuller, R
DEAD-盒蛋白家族的推定RNA解旋酶参与前mRNA剪接、rRNA成熟、核糖体组装和翻译。该蛋白家族的成员已经在从大肠杆菌到人类的生物体中被鉴定，但是除了翻译起始因子4A之外，还没有关于来自植物的其他DEAD-box蛋白的表征的报道。在这里，我们报告的DEAD-hox蛋白家族的一个新成员，植物RNA解旋酶75（PRH 75）。PRH 75位于细胞核中，包含两个用于RNA结合的结构域。一个位于C末端，类似于核定位RNA结合蛋白的RGG RNA结合结构域。另一个位于氨基酸308和622之间，该区域包含DEAD盒蛋白特有的保守基序Vt，被称为eIF-4A的RNA结合位点。N-末端81个氨基酸足以用于蛋白质的核靶向。北方和Western印迹分析表明PRH 75主要在年轻和快速发育的组织中表达。纯化的重组PRH 75具有弱的ATP酶活性，其几乎不被RNA配体刺激。通过甘油梯度离心和Superdex 200柱上的凝胶过滤对菠菜全细胞提取物进行分级，表明该蛋白质以约500 kDa的复合物存在。PRH 75可能的生物学功能以及在其模块化的一级结构的背景下的结构-功能关系进行了讨论。
The putative RNA helicases of the DEAD-box protein family are involved in pre-mRNA splicing, rRNA maturation, ribosome assembly, and translation. Members of this protein family have been identified in organisms from Escherichia coli to humans, but except for the translation initiation factor 4A, there have been no reports on the characterization of other DEAD-box proteins from plants. Here we report on a novel member of the DEAD-hox protein family, the plant RNA helicase 75 (PRH75). PRH75 is localized in the nucleus and contains two domains for RNA binding. One is located at the C terminus and is similar to RGG RNA-binding domains of nucleus-localized RNA-binding proteins. The other one is located between amino acids 308 and 622, a region containing the conserved motif Vt characteristic of DEAD-box proteins and known as the RNA-binding site of eIF-4A. The N-terminal 81 amino acids are sufficient for nuclear targeting of the protein. Northern and Western blot analyses show that PRH75 is mainly expressed in young and rapidly developing tissues. The purified recombinant PRH75 has a weak ATPase activity which is barely stimulated by RNA ligands. The fractionation of spinach whole-cell extracts by glycerol gradient centrifugation and gel filtration on a Superdex 200 column shows that the protein exists in a complex of about 500 kDa. Possible biological functions of PRH75 as well as structure-function relationships in the context of its modular primary structure are discussed.