Purnell M P, Stewart G R, Botella J R
Department of Botany, University of Queensland, Brisbane, Australia.
Gene. 1997 Feb 28;186(2):249-54. doi: 10.1016/s0378-1119(96)00716-0.
A full-length cDNA (legdh1) has been cloned encoding glutamate dehydrogenase (GDH) from tomato (Lycopersicon esculentum L.). legdh1 is 1568 bp long and contains an open reading frame encoding a 44.8 kDa polypeptide with a putative mitochondrial-matrix-targeting pre-sequence at its N-terminus. Southern analysis indicates the existence of one copy of legdh1 per haploid genome, and no closely related genes were detected by Southern analysis at low stringency. We hypothesise that in tomato, the two GDH subunits may arise from post-transcriptional modifications of a single gene. Northern analysis reveals high expression of legdh1 in roots, lower levels of expression in stems, flowers and leaves, and no detectable expression in fruits. In general, there was no correlation between steady-state mRNA level and protein activity in the tissues analysed, again suggesting the importance of post-transcriptional events in the regulation of GDH. Comparison of cloned plant GDH proteins reveals a high degree of homology throughout the sequence except for a very specific, highly divergent region.
已从番茄（Lycopersicon esculentum L.）中克隆出一个编码谷氨酸脱氢酶（GDH）的全长cDNA（legdh1）。legdh1长1568 bp，包含一个开放阅读框，编码一个44.8 kDa的多肽，其N端有一个假定的线粒体基质靶向前序列。Southern分析表明，单倍体基因组中存在一个legdh1拷贝，在低严谨度下Southern分析未检测到密切相关的基因。我们推测，在番茄中，两个GDH亚基可能来自单个基因的转录后修饰。Northern分析显示，legdh1在根中高表达，在茎、花和叶中表达水平较低，在果实中未检测到表达。总体而言，在所分析的组织中，稳态mRNA水平与蛋白质活性之间没有相关性，这再次表明转录后事件在GDH调节中的重要性。对克隆的植物GDH蛋白进行比较发现，除了一个非常特殊、高度不同的区域外，整个序列具有高度同源性。
