Schroder G, Fruhling M, Puhler A, Perlick A M
Universitat Bielefeld, Lehrstuhl fur Genetik, Germany.
Plant Mol Biol. 1997 Jan;33(1):113-23. doi: 10.1023/a:1005779116272.
Four different transcript sequences encoding gene products with an unusually high glycine content were identified in Vicia faba root nodules. Northern blot analysis revealed a strong nodule specific expression of the corresponding genes. Time course experiments showed that two of these genes were transcribed before the onset of leghemoglobin expression and hence were designated VfENOD-GRP2 and VfENOD-GRP5, whereas the first detection of VfNOD-GRP1 and VfNOD-GRP4 transcripts coincided with the appearance of leghemoglobin transcripts in V. faba root nodules. A characteristic feature of all encoded nodulins was a hydrophobic N-terminus, which in the case of the nodulins ENOD-GRP2 and ENOD-GRP5 has the characteristics of a signal peptide. Such a structure is comparable to other plant glycine-rich proteins decribed as components of the plant cell wall. Based on tissue print hybridizations, we found that VfNOD-GRP1, VfENOD-GRP2 and VfNOD-GRP4 were expressed in the interzone II-III and in the whole nitrogen-fixing zone III. In contrast to VfENOD-GRP2 and VfNOD-GRP4, the signal intensity of hybridizing VfNOD-GRP1 transcripts was slightly reduced in the more proximal part of broad bean root nodules. Apart from the interzone II-III and the nitrogen fixing zone III, VfENOD-GRP5 RNA was also detected in large areas of the prefixing zone II.
在蚕豆根瘤中鉴定出四种不同的转录本序列，其编码的基因产物具有异常高的甘氨酸含量。Northern杂交分析显示相应基因具有强烈的根瘤特异性表达。时间进程实验表明，其中两个基因在豆血红蛋白表达开始之前就已转录，因此被命名为VfENOD-GRP2和VfENOD-GRP5，而VfNOD-GRP1和VfNOD-GRP4转录本的首次检测与蚕豆根瘤中豆血红蛋白转录本的出现同时发生。所有编码的根瘤蛋白的一个特征是疏水性的N端，就根瘤蛋白ENOD-GRP2和ENOD-GRP5而言，它具有信号肽的特征。这种结构与被描述为植物细胞壁成分的其他富含甘氨酸的植物蛋白相似。基于组织印记杂交，我们发现VfNOD-GRP1、VfENOD-GRP2和VfNOD-GRP4在II-III区和整个固氮III区表达。与VfENOD-GRP2和VfNOD-GRP4不同，在蚕豆根瘤近端部分，杂交的VfNOD-GRP1转录本的信号强度略有降低。除了II-III区和固氮III区外，在II区的大片区域也检测到了VfENOD-GRP5 RNA。
