Boroń L J, Legocki A B
Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań.
Gene. 1993 Dec 22;136(1-2):95-102. doi: 10.1016/0378-1119(93)90452-9.
Glutamine synthetase (GS)-encoding genes in Lupinus luteus constitute a small family of genes showing different expression patterns [Boroń et al., Acta Biochim. Polon. 36 (1989) 295-301]. One member of this family, the LlNGS1 gene, is strongly induced in root nodules close to the onset of nitrogen fixation and is referred to as a nodule-enhanced GS gene. We present here the structure of the nodule-enhanced LlNGS1 gene, the first gene of this class which has been sequenced. LlNGS1 is composed of twelve exons and shows structural similarity to the GS gene from Medicago sativa, indicating structure conservation of GS genes in legumes. Comparison of protein coding regions, as well as 5'-untranslated regions derived from LlNGS1 and a Lupinus angustifolius pGS5 GS cDNA clone [Grant et al., Plant Mol. Biol. 13 (1989) 481-490], revealed a high degree of shared identity between both genes, indicating that they are orthologous. The sequence of the LlNGS1 5'-flanking region (2.3 kb) contains several elements implicated in regulation of nodulin genes, as well as other characteristic DNA motifs. RNA blot hybridization analysis carried out using a probe corresponding to the LlNGS1 3'-untranslated region revealed that this gene is also transcribed in leaves, but at a barely detectable level.
羽扇豆中的谷氨酰胺合成酶（GS）编码基因构成了一个小基因家族，这些基因呈现出不同的表达模式[博罗恩等人，《波兰生物化学学报》36（1989）295 - 301]。这个家族的一个成员，即LlNGS1基因，在根瘤中靠近固氮开始时被强烈诱导，被称为结节增强型GS基因。我们在此展示结节增强型LlNGS1基因的结构，这是该类别的第一个已测序基因。LlNGS1由十二个外显子组成，与紫花苜蓿的GS基因显示出结构相似性，表明豆科植物中GS基因的结构保守性。对蛋白质编码区以及源自LlNGS1和羽扇豆窄叶pGS5 GS cDNA克隆[格兰特等人，《植物分子生物学》13（1989）481 - 490]的5'非翻译区进行比较，发现这两个基因之间有高度的共享同一性，表明它们是直系同源的。LlNGS1 5'侧翼区（2.3 kb）的序列包含几个与结瘤素基因调控有关的元件，以及其他特征性DNA基序。使用与LlNGS1 3'非翻译区对应的探针进行的RNA印迹杂交分析表明，该基因在叶片中也有转录，但水平极低，几乎检测不到。
