Hirano H Y, Sano Y
Graduate School of Agricultural and Life Sciences, University of Tokyo, Yayoi, Japan.
Genes Genet Syst. 2000 Oct;75(5):245-9. doi: 10.1266/ggs.75.245.
The Waxy (Wx) gene controls amylose synthesis in rice (Oryza sativa) and its expression is regulated organ-specifically. The Wx gene is expressed in the endosperm and pollen but not in other organs. In order to know whether Wx gene regulation is the same in the endosperm and pollen, we compared expression patterns of the rice Wx gene in these two organs by immunoblot analysis. We focused on the allelic differences (Wxa and Wxb), cool temperature response and effects of the mutation at the du loci. The results obtained are as follows. First, the quantitative regulation depending on two alleles, Wxa and Wxb, was common to both organs; Wx protein levels from the Wxa allele were about 10-fold higher than those from the Wxb allele in the pollen as well as in the endosperm. Second, in both the endosperm and pollen, expression of the Wxb gene, but not the Wxa gene, was enhanced in response to cool temperature. In contrast to these two types of regulation, analysis of two du mutants, 2035 (du1) and 76-3 (du2), revealed that the pattern of reduction in Wx protein levels in the pollen was distinct from that in the endosperm, suggesting that functions of the two du+ genes differ in these two organs.
蜡质（Wx）基因控制水稻（Oryza sativa）中直链淀粉的合成，其表达具有器官特异性调控。Wx基因在胚乳和花粉中表达，但在其他器官中不表达。为了了解Wx基因在胚乳和花粉中的调控是否相同，我们通过免疫印迹分析比较了水稻Wx基因在这两个器官中的表达模式。我们重点研究了等位基因差异（Wxa和Wxb）、低温响应以及du位点突变的影响。得到的结果如下。首先，依赖于Wxa和Wxb这两个等位基因的定量调控在两个器官中是共同的；在花粉和胚乳中，来自Wxa等位基因的Wx蛋白水平比来自Wxb等位基因的高约10倍。其次，在胚乳和花粉中，Wxb基因而非Wxa基因的表达在低温响应下增强。与这两种调控类型不同，对两个du突变体2035（du1）和76 - 3（du2）的分析表明，花粉中Wx蛋白水平降低的模式与胚乳中的不同，这表明两个du +基因在这两个器官中的功能不同。
