Jeon J S, Lee S, Jung K H, Jun S H, Kim C, An G
Department of Life Science and National Research Laboratory of Plant Functional Genomics, Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea.
Plant Physiol. 2000 Jul;123(3):1005-14. doi: 10.1104/pp.123.3.1005.
The genomic clone encoding an alpha-tubulin, OsTubA1, has been isolated from rice (Oryza sativa L.). The gene consists of four exons and three introns. RNA-blot analysis showed that the gene is strongly expressed in actively dividing tissues, including root tips, young leaves, and young flowers. Analysis of chimeric fusions between OsTubA1 and beta-glucuronidase (GUS) revealed that the intron 1 was required for high-level GUS expression in actively dividing tissues, corresponding with normal expression pattern of OsTubA1. Fusion constructs lacking the intron 1 showed more GUS staining in mature tissues rather than young tissues. When the intron 1 was placed at the distal region from 5'-upstream region or at the 3'-untranslated region, no enhancement of GUS expression was observed. Sequential deletions of the OsTubA1 intron 1 brought about a gradual reduction of GUS activity in calli. These results suggest that tissue-preferential expression of the OsTubA1 gene is mediated by the intron 1 and that it may be involved in a mechanism for an efficient RNA splicing that is position dependent.
已从水稻（Oryza sativa L.）中分离出编码α-微管蛋白的基因组克隆OsTubA1。该基因由四个外显子和三个内含子组成。RNA印迹分析表明，该基因在包括根尖、幼叶和幼花在内的活跃分裂组织中强烈表达。对OsTubA1与β-葡萄糖醛酸酶（GUS）的嵌合融合体分析表明，内含子1是活跃分裂组织中高水平GUS表达所必需的，这与OsTubA1的正常表达模式相对应。缺少内含子1的融合构建体在成熟组织而非幼嫩组织中显示出更多的GUS染色。当内含子1置于5'-上游区域的远端或3'-非翻译区域时，未观察到GUS表达增强。对OsTubA1内含子1进行连续缺失导致愈伤组织中GUS活性逐渐降低。这些结果表明，OsTubA1基因的组织优先表达由内含子1介导，并且它可能参与了一种位置依赖性的有效RNA剪接机制。
