Shin Byongchul, Choi Goh, Yi Hankuil, Yang Seungchan, Cho Insook, Kim Jonghyun, Lee Seunghee, Paek Nam-Chon, Kim Jae-Hong, Song Pill-Soon, Choi Giltsu
Kumho Life and Environmental Science Laboratory, 1 Oryong-dong, Buk-gu, Gwangju 500-712 Korea.
Plant J. 2002 Apr;30(1):23-32. doi: 10.1046/j.1365-313x.2002.01264.x.
Light is an important environmental signal that governs plant growth and development. One important light-signalling component involved in plant light responses is COP1. The pleiotropic phenotypes of the cop1 mutant suggest that COP1 regulates not only photomorphogenesis, but also other developmental processes. We investigated the role of COP1 by identifying genes that are regulated by COP1. We report that AtMYB21, a gene encoding a flower-specific transcription factor, is ectopically expressed in the cop1 mutant. Analysis shows that dark-grown transgenic seedlings expressing AtMYB21-GR fusion protein display some features of the cop1 mutant, including decreased hypocotyl cell expansion, open cotyledons in the dark, and seedling lethality in the presence of dexamethasone. Light-grown adult transgenic plants expressing AtMYB21 have shorter stems, smaller and narrower leaves, narrower petals, and malformed carpels. In addition, we show that AtMYB21 directly regulates two genes that are also expressed more abundantly in the cop1 mutant. The results indicate that COP1 is required to repress the AtMYB21 gene in seedlings, and the pleiotropic phenotypes shown in the cop1 mutant are due to the combination of misregulation of genuine light-signalling components and other tissue-specific factors.
光是一种重要的环境信号，它调控着植物的生长和发育。参与植物光反应的一个重要光信号组分是COP1。cop1突变体的多效表型表明，COP1不仅调节光形态建成，还调节其他发育过程。我们通过鉴定受COP1调控的基因来研究COP1的作用。我们报道，编码花特异性转录因子的基因AtMYB21在cop1突变体中异位表达。分析表明，黑暗中生长的表达AtMYB21-GR融合蛋白的转基因幼苗表现出cop1突变体的一些特征，包括下胚轴细胞扩展减少、黑暗中开放的子叶以及在存在地塞米松的情况下幼苗致死。光照下生长的表达AtMYB21的成年转基因植物茎更短，叶片更小更窄，花瓣更窄，心皮畸形。此外，我们表明AtMYB21直接调控两个在cop1突变体中也更大量表达的基因。结果表明，COP1在幼苗中是抑制AtMYB21基因所必需的，cop1突变体中显示的多效表型是由于真正的光信号组分和其他组织特异性因子的调控异常共同作用的结果。
