Goosey L, Palecanda L, Sharrock R A
Department of Biology, Montana State University, Bozeman 59717, USA.
Plant Physiol. 1997 Nov;115(3):959-69. doi: 10.1104/pp.115.3.959.
The Arabidopsis thaliana phyB, phyD, and phyE phytochrome apoproteins show higher amino acid sequence similarity to each other than to phyA or phyC, they are the most recently evolved members of this photoreceptor family, and they may interact in regulating photomorphogenesis. The expression patterns of translational fusions of the 5' upstream regions of the PHYB, PHYD, and PHYE genes to the beta-glucuronidase (GUS) coding sequence were compared. PD-GUS and PE-GUS fusions were 5- to 10-fold less active than a PB-GUS fusion, but all three promoter regions drove expression of the reporter gene in all stages of the plant's life cycle. Over the first 10 d of seedling growth, the PHYB and PHYD promoters were more active in the dark than in the light, whereas the opposite was true of the PHYE promoter. Unlike the PB-GUS construct, which was expressed in most parts of seedlings and mature plants, the PD-GUS and PE-GUS transgenes showed differential expression, notably in leaves, flower organs, and root tips. Tissue sections showed that the three promoters are coexpressed in at least some leaf cells. Hence, the PHYB, PHYD, and PHYE genes differ in expression pattern but these patterns overlap and interaction of these receptor forms within individual cells is possible.
拟南芥的phyB、phyD和phyE光敏色素脱辅基蛋白彼此之间的氨基酸序列相似性高于它们与phyA或phyC的相似性，它们是这个光受体家族中最近进化出来的成员，并且它们可能在调节光形态建成中相互作用。比较了PHYB、PHYD和PHYE基因5'上游区域与β-葡萄糖醛酸酶（GUS）编码序列的翻译融合体的表达模式。PD-GUS和PE-GUS融合体的活性比PB-GUS融合体低5至10倍，但所有三个启动子区域在植物生命周期的所有阶段都驱动报告基因的表达。在幼苗生长的前10天，PHYB和PHYD启动子在黑暗中比在光下更活跃，而PHYE启动子则相反。与在幼苗和成熟植物的大部分部位都有表达的PB-GUS构建体不同，PD-GUS和PE-GUS转基因表现出差异表达，特别是在叶片、花器官和根尖。组织切片显示这三个启动子至少在一些叶细胞中共同表达。因此，PHYB、PHYD和PHYE基因在表达模式上存在差异，但这些模式有重叠，并且这些受体形式在单个细胞内可能相互作用。
