Jeon J S, Chung Y Y, Lee S, Yi G H, Oh B G, An G
Department of Life Science, Pohang University of Science and Technology, Korea.
Plant Mol Biol. 1999 Jan;39(1):35-44. doi: 10.1023/a:1006157603096.
An anther-specific cDNA clone of rice, RA8, was isolated from an anther cDNA library by differential screening. RNA blot analysis indicated that the RA8 transcript is present specifically in anthers and the transcript level increased as flowers matured, reaching the highest level in mature flowers. The RA8 clone contains an open reading frame of 264 amino acid residues with a hydrophobic N-terminal region. The deduced amino acid sequences did not show significant homology to any known sequences. Genomic DNA blot analysis showed that RA8 is a single-copy gene. A genomic clone corresponding to the RA8 cDNA was isolated and its promoter region was fused to the beta-glucuronidase (GUS) gene. Transgenic rice plants exhibited anther-specific expression of the GUS reporter gene. Histochemical GUS analysis showed that the RA8 promoter was active in the tapetum, endothecium, and connective tissues of anthers. Experiments showed that expression of the gene starts when microspores are released from tetrads, and it reaches to the maximum level at the late vacuolated-pollen stage. The RA8 promoter may be useful for controlling gene expression in anthers of cereal plants and for generating male-sterile plants.
通过差异筛选从水稻花药cDNA文库中分离出一个水稻花药特异性cDNA克隆RA8。RNA印迹分析表明，RA8转录本仅在花药中存在，且随着花的成熟转录本水平升高，在成熟花中达到最高水平。RA8克隆包含一个由264个氨基酸残基组成的开放阅读框，其N端区域具有疏水性。推导的氨基酸序列与任何已知序列均无明显同源性。基因组DNA印迹分析表明RA8是一个单拷贝基因。分离出与RA8 cDNA对应的基因组克隆，并将其启动子区域与β-葡萄糖醛酸酶（GUS）基因融合。转基因水稻植株表现出GUS报告基因的花药特异性表达。组织化学GUS分析表明，RA8启动子在花药的绒毡层、内壁和连接组织中具有活性。实验表明，该基因在小孢子从四分体中释放时开始表达，并在液泡化花粉后期达到最高水平。RA8启动子可能有助于控制谷类作物花药中的基因表达以及培育雄性不育植株。
