Uribe X, Torres M A, Capellades M, Puigdomènech P, Rigau J
Department de Genètica Molecular, Centre d'Investigació i Desenvolupament, Consejo Superior de Investigaciones Científicas, Barcelona, Spain.
Plant Mol Biol. 1998 Aug;37(6):1069-78. doi: 10.1023/a:1006067710312.
In the past few years many alpha- and beta-tubulin genes of different organisms have been cloned and studied, and in most systems studied they constitute multigene families. In plants, most studies have been done in Arabidopsis thaliana and Zea mays. In this paper, the study of mRNA accumulation by in situ hybridization and the activity of three maize alpha-tubulin gene promoters (tua1, tua2 and tua3) in transgenic tobacco plants are described. In maize, the expression of these three tubulin isotypes differ in the root and shoot apex and is associated with different groups of cells throughout the distinct stages of cell differentiation. In transgenic tobacco plants the promoters of the genes, fused to the uidA reporter gene (GUS), direct expression to the same tissues observed by in situ hybridization experiments. The tua1 promoter is mainly active in cortex-producing meristematic cells and in pollen, whereas tua3 is active in cells which are differentiating to form vascular bundles in the root and shoot apices. The accumulation of tua2 mRNA is detected by RNA blot in a similar form as tua1, but at a very much low level. In situ hybridization indicates that the tua2 mRNA specifically accumulates in the maize root epidermis. No GUS staining was detected in transgenic tobacco plants with the tua2 promoter. The difference in expression of the specific genes may be linked to processes where microtubules have different functions, suggesting that in plants, as in animals, there are differences in the function of the tubulin isotypes.
在过去几年中，不同生物体的许多α-和β-微管蛋白基因已被克隆和研究，在大多数研究的系统中，它们构成了多基因家族。在植物中，大多数研究是在拟南芥和玉米中进行的。本文描述了通过原位杂交研究mRNA积累以及三个玉米α-微管蛋白基因启动子（tua1、tua2和tua3）在转基因烟草植物中的活性。在玉米中，这三种微管蛋白亚型在根和茎尖的表达不同，并且在细胞分化的不同阶段与不同的细胞群相关。在转基因烟草植物中，与uidA报告基因（GUS）融合的基因启动子将表达导向原位杂交实验中观察到的相同组织。tua1启动子主要在产生皮层的分生细胞和花粉中活跃，而tua3在根和茎尖中正在分化形成维管束的细胞中活跃。通过RNA印迹检测到tua2 mRNA的积累形式与tua1相似，但水平非常低。原位杂交表明tua2 mRNA特异性地积累在玉米根表皮中。在带有tua2启动子的转基因烟草植物中未检测到GUS染色。特定基因表达的差异可能与微管具有不同功能的过程有关，这表明在植物中，如同在动物中一样，微管蛋白亚型的功能存在差异。
