Kliebenstein Daniel J, Lim Jackie E, Landry Laurie G, Last Robert L
The Boyce Thompson Institute for Plant Research and Section of Genetics and Development, Cornell University, Ithaca, New York 14853, USA.
Plant Physiol. 2002 Sep;130(1):234-43. doi: 10.1104/pp.005041.
To further our understanding of how plants defend against the harmful effects of ultraviolet (UV) light, we characterized an Arabidopsis mutant hypersensitive to UV-B. This mutant, UV resistance locus 8-1 (uvr8-1), contains a single recessive mutation at the bottom of chromosome 5. Fine-scale mapping localized uvr8-1 to a 21-kb locus containing five predicted open reading frames. Sequencing of this entire region revealed that the uvr8-1 allele contains a 15-nucleotide deletion in a gene similar to the human guanine nucleotide exchange factor regulator of chromatin condensation 1. This mutation reduces the UV-B-mediated induction of flavonoids and blocks chalcone synthase mRNA and protein induction. In contrast, uvr8-1 has enhanced induction of PR1 and PR5 proteins in response to UV-B, an indication of increased UV-B injury. These results suggest that UVR8 acts in a UV-B signal transduction pathway leading to induction of flavonoid biosynthesis.
为了进一步了解植物如何抵御紫外线（UV）的有害影响，我们对一个对UV-B高度敏感的拟南芥突变体进行了特征分析。这个突变体，紫外线抗性位点8-1（uvr8-1），在第5号染色体末端含有一个单隐性突变。精细定位将uvr8-1定位到一个21 kb的位点，该位点包含五个预测的开放阅读框。对整个区域进行测序发现，uvr8-1等位基因在一个与人类染色质凝聚1的鸟嘌呤核苷酸交换因子调节因子相似的基因中存在15个核苷酸的缺失。这种突变减少了UV-B介导的类黄酮诱导，并阻断了查尔酮合酶mRNA和蛋白质的诱导。相反，uvr8-1对UV-B的反应增强了PR1和PR5蛋白的诱导，这表明UV-B损伤增加。这些结果表明，UVR8在导致类黄酮生物合成诱导的UV-B信号转导途径中起作用。
