Estévez J M, Cantero A, Romero C, Kawaide H, Jiménez L F, Kuzuyama T, Seto H, Kamiya Y, León P
Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001 Chamilpa, Apdo Postal 510-3 Cuernavaca Morelos 62271, México.
Plant Physiol. 2000 Sep;124(1):95-104. doi: 10.1104/pp.124.1.95.
The discovery of the 2-C-methyl-D-erythritol-4-phosphate pathway for the biosynthesis of isoprenoids raises the important question of the nature and regulation of the enzymes involved in this pathway. CLA1, a gene previously isolated from Arabidopsis, encodes the first enzyme of the 2-C-methyl-D-erythritol-4-phosphate pathway, 1-deoxy-D-xylulose-5-phosphate synthase. We demonstrate this enzyme activity by complementation of the cla1-1 mutant phenotype and by direct enzymatic assays. Based on mRNA and protein expression patterns this enzyme is expressed mainly in developing photosynthetic and non-photosynthetic tissues. The beta-glucuronidase expression pattern driven from the CLA1 gene regulatory region supports the northern and protein data while also showing that this gene has some level of expression in most tissues of the plant. A mutation in the CLA1 gene interferes with the normal development of chloroplasts and etioplasts, but does not seem to affect amyloplast structure. Microscopic analysis also shows a pleiotropic effect of the CLA1 gene mutation in mesophyll tissue formation.
2-C-甲基-D-赤藓糖醇-4-磷酸途径用于类异戊二烯生物合成的发现，引发了关于该途径中相关酶的性质和调控这一重要问题。CLA1是先前从拟南芥中分离出的一个基因，它编码2-C-甲基-D-赤藓糖醇-4-磷酸途径的首个酶，即1-脱氧-D-木酮糖-5-磷酸合酶。我们通过对cla1-1突变体表型的互补以及直接酶促测定来证明这种酶活性。基于mRNA和蛋白质表达模式，该酶主要在发育中的光合组织和非光合组织中表达。由CLA1基因调控区驱动的β-葡萄糖醛酸酶表达模式支持了Northern杂交和蛋白质数据，同时也表明该基因在植物的大多数组织中都有一定水平的表达。CLA1基因突变会干扰叶绿体和黄化质体的正常发育，但似乎不影响造粉体结构。显微镜分析还显示CLA1基因突变在叶肉组织形成中具有多效性作用。
