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The plant‐specific transcription factor gene NAC 103 is induced by b ZIP 60 through a new cis ‐regulatory element to modulate the unfolded protein response in A rabidopsis
Author(s) -
Sun Ling,
Yang ZhengTing,
Song ZeTing,
Wang MeiJing,
Sun Le,
Lu SunJie,
Liu JianXiang
Publication year - 2013
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12287
Subject(s) - arabidopsis , unfolded protein response , bimolecular fluorescence complementation , transcription factor , endoplasmic reticulum , microbiology and biotechnology , reporter gene , promoter , biology , electrophoretic mobility shift assay , arabidopsis thaliana , protein fragment complementation assay , complementation , gene , negative regulatory element , mutant , gene expression , genetics
Summary The unfolded protein response ( UPR ) plays important roles in plant development and plant–pathogen interactions, as well as in plant adaptation to adverse environmental stresses. Previously b ZIP 28 and b ZIP 60 have been identified as important UPR regulators for mitigating the endoplasmic reticulum ( ER ) stress in A rabidopsis thaliana . Here we report the biological function of NAC 103 in a novel transcriptional regulatory cascade, connecting b ZIP 60 to the UPR downstream genes in A rabidopsis. Expression of NAC 103 was induced by ER stress, and was completely abolished in the b ZIP 60 null mutant. A new ER stress‐responsive cis ‐element UPRE – III ( TCATCG ) on the NAC 103 promoter was identified, and trans ‐activation of UPRE – III by b ZIP 60 was confirmed in both yeast cells and Arabidopsis protoplasts. The direct binding of b ZIP 60 to UPRE – III ‐containing DNA was also demonstrated in an electrophoretic mobility shift assay. NAC 103 formed homodimers in yeast two‐hybrid and bimolecular fluorescence complementation assays. It had transcriptional activation activity and was localized in the nucleus. Over‐expression of NAC 103 had pleiotropic effects on plant growth, and induced expression of several UPR downstream genes in Arabidopsis under normal growth conditions. The activation of UPR gene promoters by NAC 103 was also confirmed in effector/reporter protoplast assays. Thus, our study demonstrates a transcriptional regulatory cascade in which NAC 103 relays ER stress signals from b ZIP 60 to UPR downstream genes through a newly identified ER stress cis ‐element ( UPRE – III ) and transcriptional activation activity of its encoded protein NAC 103.