Zhou D X, Kim Y J, Li Y F, Carol P, Mache R
Laboratoire de Génétique Moléculaire des Plantes, Université Joseph Fourier, Grenoble, France.
Mol Gen Genet. 1998 Feb;257(4):387-91. doi: 10.1007/s004380050662.
COP1 is a negative regulator of Arabidopsis light-dependent development. Mutation of the COP1 locus causes constitutive photomorphogenesis in the dark. Here, we report the identification of an isoform of the COP1 protein, named COP1b, which is generated by alternative splicing. COP1b has a 60-amino acid deletion in the WD-40 repeat domain relative to the full-length COP1. This splicing step is light-independent and takes place mostly in mature seeds and in germinating seedlings. Transgenic Arabidopsis plants that overexpress COP1b show a de-etiolated phenotype in the dark, with a short hypocotyl, open and developed cotyledons. The transgenic seedlings are adult-lethal. These phenotypes closely resemble that of severe cop-1 mutants, indicating that COP1b has a dominant negative effect on COP1 function.
COP1是拟南芥光依赖型发育的负调控因子。COP1基因座的突变会导致在黑暗中组成型光形态建成。在此，我们报告了一种COP1蛋白异构体的鉴定，名为COP1b，它是通过可变剪接产生的。相对于全长COP1，COP1b在WD-40重复结构域中有一个60个氨基酸的缺失。这一剪接步骤不依赖光照，主要发生在成熟种子和萌发的幼苗中。过表达COP1b的转基因拟南芥植株在黑暗中表现出去黄化表型，下胚轴短，子叶开放且发育。转基因幼苗是成年致死的。这些表型与严重的cop-1突变体非常相似，表明COP1b对COP1功能具有显性负效应。
