Open AccessVirus Induction of Heat Shock Protein 70 Reflects a General Response to Protein Accumulation in the Plant Cytosol
Author(s) -
Frederic Aparicio,
Colwyn M. Thomas,
Carsten W. Lederer,
Yan Niu,
Daowen Wang,
Andrew J. Maule
Publication year - 2005
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.104.058958
Subject(s) - arabidopsis , biology , nicotiana benthamiana , endoplasmic reticulum , hsp70 , heat shock protein , hspa12a , microbiology and biotechnology , arabidopsis thaliana , gene , hsf1 , bimolecular fluorescence complementation , genetics , mutant
Different cytoplasmically replicating RNA viruses were shown to induce a specific subset of heat-inducible heat shock protein 70 (HSP70) genes in Arabidopsis (Arabidopsis thaliana). To identify the inducing principle, a promoterreporter system was developed for the facile analysis of differentially responding Arabidopsis HSP70 genes, by infiltration into Nicotiana benthamiana leaves. Through transient expression of individual viral cistrons or through deletion analysis of a viral replicon, we were unable to identify a unique inducer of HSP70. However, there was a positive correlation between the translatability of the test construct and the differential induction of HSP70. Since these data implied a lack of specificity in the induction process, we also expressed a random series of cytosolically targeted Arabidopsis genes and showed that these also differentially induced HSP70. Through a comparison of different promoterreporter constructs and through measurements of the steady-state levels of the individual proteins, it appeared that the HSP70 response reflected the ability of the cytosol to sense individual properties of particular proteins when expressed at high levels. This phenomenon is reminiscent of the unfolded protein response observed when the induced accumulation of proteins in the endoplasmic reticulum also induces a specific suite of chaperones.