A nodulin/glutamine synthetase-like fusion protein is implicated in the regulation of root morphogenesis and in signalling triggered by flagellin
A nodulin/glutamine synthetase-like fusion protein is implicated in the regulation of root morphogenesis and in signalling triggered by flagellin
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DOI：
10.1007/s00425-011-1419-7
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发表时间：
2011-09-01
期刊：
影响因子：
4.3
通讯作者：
Binarova, Pavla
中科院分区：
文献类型：
--
作者：
Doskocilova, Anna;Plihal, Ondrej;Binarova, Pavla
我们在拟南芥中鉴定的结节蛋白/谷氨酰胺合成酶样蛋白(NodGS)是由与结节蛋白同源的N末端氨基水解酶结构域和原核生物谷氨酰胺合成酶I型的C末端结构域组成的融合蛋白，与真菌中的形态发生因子Flug蛋白同源。虽然编码NodGS同源物的基因存在于许多植物基因组中，但其产物尚未被鉴定。拟南芥NodGS以类似于700 kDa的寡聚体形式存在，主要存在于细胞质中，少量存在于微粒体膜部分。寡聚体NodGS被掺入到大的异质蛋白质复合体>；700 kDa中，并与γ-微管蛋白部分免疫共沉淀。原位和体内显微镜分析显示，NodGS信号位于细胞质中，带有内膜，特别是在核周区域。NodGS没有检测到谷氨酰胺合成酶活性。RNAi下调NodGS的表达导致植株主根变短，分生组织活性降低，根冠发育受阻。Y2H分析和公开的微阵列数据表明，NodGS在生物胁迫信号中发挥了作用。我们发现鞭毛蛋白促进了NodGS蛋白的表达，然后NodGS蛋白优先定位于核周。我们的结果表明，NodGS在根的形态发生和微生物诱导中发挥了作用。这些数据可能有助于理解广泛存在于原核生物、真菌和植物中的NodGS/Flug样融合基因家族。
The nodulin/glutamine synthetase-like protein (NodGS) that we identified proteomically in Arabidopsis thaliana is a fusion protein composed of an N-terminal amidohydrolase domain that shares homology with nodulins and a C-terminal domain of prokaryotic glutamine synthetase type I. The protein is homologous to the FluG protein, a morphogenetic factor in fungi. Although genes encoding NodGS homologues are present in many plant genomes, their products have not yet been characterized. The Arabidopsis NodGS was present in an oligomeric form of similar to 700-kDa, mainly in the cytosol, and to a lesser extent in the microsomal membrane fraction. The oligomeric NodGS was incorporated into large heterogeneous protein complexes > 700 kDa and partially co-immunoprecipitated with gamma-tubulin. In situ and in vivo microscopic analyses revealed a NodGS signal in the cytoplasm, with endomembranes, particularly in the perinuclear area. NodGS had no detectable glutamine synthetase activity. Downregulation of NodGS by RNAi resulted in plants with a short main root, reduced meristematic activity and disrupted development of the root cap. Y2H analysis and publicly available microarray data indicated a role for NodGS in biotic stress signalling. We found that flagellin enhanced the expression of the NodGS protein, which was then preferentially localized in the nuclear periphery. Our results point to a role for NodGS in root morphogenesis and microbial elicitation. These data might help in understanding the family of NodGS/FluG-like fusion genes that are widespread in prokaryotes, fungi and plants.