Kusaba Makoto, Miyahara Kenzo, Iida Shuichi, Fukuoka Hiroyuki, Takano Toshiya, Sassa Hidenori, Nishimura Minoru, Nishio Takeshi
Institute of Radiation Breeding, National Institute of Agrobiological Sciences, Ohmiya-machi, Naka-gun, Ibaraki 319-2293, Japan.
Plant Cell. 2003 Jun;15(6):1455-67. doi: 10.1105/tpc.011452.
Low glutelin content1 (Lgc1) is a dominant mutation that reduces glutelin content in rice grains. Glutelin is a major seed storage protein encoded by a multigene family. RNA gel blot and reverse transcriptase-mediated PCR analyses revealed that Lgc1 acts at the mRNA level in a similarity-dependent manner. In Lgc1 homozygotes, there is a 3.5-kb deletion between two highly similar glutelin genes that forms a tail-to-tail inverted repeat, which might produce a double-stranded RNA molecule, a potent inducer of RNA silencing. The hypothesis that Lgc1 suppresses glutelin expression via RNA silencing is supported by transgenic analysis using this Lgc1 candidate region, by reporter gene analysis, and by the detection of small interfering RNAs. In this context, Lgc1 provides an interesting example of RNA silencing occurring among genes that exhibit various levels of similarity to an RNA-silencing-inducing gene. Possible mechanisms for gene silencing of the glutelin multigene family by Lgc1 are discussed.
低谷蛋白含量1（Lgc1）是一种显性突变，可降低水稻籽粒中的谷蛋白含量。谷蛋白是由一个多基因家族编码的主要种子贮藏蛋白。RNA凝胶印迹和逆转录酶介导的PCR分析表明，Lgc1以相似性依赖的方式在mRNA水平上起作用。在Lgc1纯合子中，两个高度相似的谷蛋白基因之间存在一个3.5kb的缺失，形成了一个尾对尾的反向重复序列，这可能产生一个双链RNA分子，一种有效的RNA沉默诱导剂。通过使用该Lgc1候选区域的转基因分析、报告基因分析以及小干扰RNA的检测，支持了Lgc1通过RNA沉默抑制谷蛋白表达的假说。在此背景下，Lgc1提供了一个有趣的例子，说明RNA沉默发生在与RNA沉默诱导基因具有不同相似程度的基因之间。本文讨论了Lgc1对谷蛋白多基因家族进行基因沉默的可能机制。
