Interplay between HEAT SHOCK PROTEIN 90 and HY5 Controls PhANG Expression in Response to the GUN5 Plastid Signal  

作　　者：Peter Kindgren Louise Noren Juan de Dios Barajas Lopez Jehad Shaikhali Asa Strand 

机构地区：[1]Umea Plant Science Centre, Department of Plant Physiology, Umea University, S-901 87 Umea, Sweden

出　　处：《Molecular Plant》2012年第4期901-913,共13页分子植物（英文版）

摘　　要：The presence of genes encoding organellar proteins in different cellular compartments necessitates a tight coordination of expression by the different genomes of the eukaryotic cell. This coordination of gene expression is achieved by organelle-to-nucleus or retrograde communication. Stress-induced perturbations of the tetrapyrrole pathway trigger large changes in nuclear gene expression in plants. Recently, we identified HSP90 proteins as ligands of the pu- tative plastid signal Mg-ProtolX. In order to investigate whether the interaction between HSP90 and Mg-ProtolX is bio- logically relevant, we produced transgenic lines with reduced levels of cytosolic HSP90 in wild-type and gun5 backgrounds. Our work reveals that HSP90 proteins respond to the tetrapyrrole-mediated plastid signal to control expres- sion of photosynthesis-associated nuclear genes （PhANG） during the response to oxidative stress. We also show that the hy5 mutant is insensitive to tetrapyrrole accumulation and that Mg-ProtolX, cytosolic HSP90, and HY5 are all part of the same signaling pathway. These findings suggest that a regulatory complex controlling gene expression that includes HSP90 proteins and a transcription factor that is modified by tetrapyrroles in response to changes in the environment is evolutionarily conserved between yeast and plants.The presence of genes encoding organellar proteins in different cellular compartments necessitates a tight coordination of expression by the different genomes of the eukaryotic cell. This coordination of gene expression is achieved by organelle-to-nucleus or retrograde communication. Stress-induced perturbations of the tetrapyrrole pathway trigger large changes in nuclear gene expression in plants. Recently, we identified HSP90 proteins as ligands of the pu- tative plastid signal Mg-ProtolX. In order to investigate whether the interaction between HSP90 and Mg-ProtolX is bio- logically relevant, we produced transgenic lines with reduced levels of cytosolic HSP90 in wild-type and gun5 backgrounds. Our work reveals that HSP90 proteins respond to the tetrapyrrole-mediated plastid signal to control expres- sion of photosynthesis-associated nuclear genes （PhANG） during the response to oxidative stress. We also show that the hy5 mutant is insensitive to tetrapyrrole accumulation and that Mg-ProtolX, cytosolic HSP90, and HY5 are all part of the same signaling pathway. These findings suggest that a regulatory complex controlling gene expression that includes HSP90 proteins and a transcription factor that is modified by tetrapyrroles in response to changes in the environment is evolutionarily conserved between yeast and plants.

关 键 词：abiotic/environmental stress cell signaling organelle biogenesis/function. 

分 类 号：Q949.718.2[生物学—植物学] S858.31[农业科学—临床兽医学]