| Abstract Detail
Intracellular Signaling Watanabe, Naohide [1], Lam, Eric [2]. Bax Inhibitor-1 Modulates Endoplasmic Reticulum Stress-mediated Programmed Cell Death in Arabidopsis. The components and pathways that regulate programmed cell death (PCD) in plants remain poorly understood. Bax inhibitor-1 (BI-1), a conserved endoplasmic reticulum (ER) protein, has been characterized as cell death suppressor in mammals and plants. However, a role of BI-1 linked to ER homeostasis and its related stress response is largely unknown in plants. Here we describe the impact of ER stress on Arabidopsis seedlings and provide genetic evidence for the role of BI-1 as a modulator of ER stress-induced PCD. We found that treatment of Arabidopsis seedlings with tunicamycin (TM), an inhibitor of N-linked glycosylation and an inducer of ER stress by triggering accumulation of unfolded proteins in ER, results in strong inhibition of root growth and loss of survival accompanied by typical hallmarks of PCD such as accumulation of hydrogen peroxide, chromatin condensation and oligonucleosomal fragmentation of nuclear DNA. These phenotypes are alleviated by co-treatment with a chemical chaperone (4-phenylbutyric acid) that can reduce the load of misfolded protein in ER. Expression of AtBI1 mRNA and its promoter activity are increased dramatically prior to initiation of TM-induced PCD. Compared with wild-type plants, two AtBI1 mutants (atbi1-1 and atbi1-2) exhibit hypersensitivity to TM with accelerated PCD progression. Conversely, overexpressing AtBI1 remarkably reduces the sensitivity of Arabidopsis seedlings to TM. Similar results were obtained with other types of ER stress inducers (cyclopiazonic acid and L-azetidine-2-carboxylic acid). We propose that AtBI1 plays a pivotal role as a positive regulator of cell survival involved in the protection of plants during ER stress responses.
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Related Links:
Lam Lab web
1 - Rutgers, The State University of New Jersey, Biotech Center, 59 Dudley Road, New Brunswick, NJ, 08901, United States
2 - Rutgers, The State University of New Jersey, Biotech Center
Keywords:
BI-1
Programmed Cell Death
ER stress
abiotic stress.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P33016
Abstract ID:1064 |
