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 My group focuses on the dissection of ethylene signal transduction using Arabidopsis as a model plant while roles of ethylene in the regulation of growth and development in the rice plant are being investigated.
Principal Investigator: Dr. Qi-Guang Wen (Chi-Kuang Wen), Professor. Email: cwen@sippe.ac.cn; qgwen@sibs.ac.cn
Staff: Zhong-Ming Yin, Research Assistant; Dr. Qian Liu, Research Assistant; Pei-Li Liu (emeritus)
Graduate Students: Li-Ping Qiu; Chan Xu; Jing Yu; Wei Zhang; Qin Wang; Ai-Bei Xu; Cong-Yao Xu
Joint Graduate Students: Qian Liu, 2004 (PhD)
A Study of Ethylene Receptor Cooperativity and Isolation of New Signaling Components
Arabidopsis has five ethylene receptors and they are functionally redundant, making it challenging to characterize individual receptors. To study function of individual receptors, we examined receptor signaling of ETR1 and ERS1 in receptor-defective mutants. Our data show that, in addition to repressing ethylene response, ERS1 also represses total receptor signal output, implying functional divergence of ethylene receptors. We further examined constitutive receptor signaling in receptor-defective mutants. Receptor isoforms with constitutive signaling activity failed to convey signal output in the absence of other receptor subtypes, indicating cooperativity is essential to receptor signal output. This hypothesis is strengthened by the result that neither etr1-1 nor ers1-1 was able to confer ethylene insensitivity in quadruple receptor mutants. To further isolate new signaling components on the signal transduction pathway, we identified a CTR1-independent signal transduction pathway; mutations disrupting the pathway have been verified and corresponding genes are being mapped. We artificially created an AKL1-ETR1 fusion protein, whose ectopic expression led to ethylene insensitivity and recued the ctr1-1 mutant phenotype, possibly due to gain of function. We thus utilized this material to isolate components involved in the AKL1-ETR1 function by suppressor screen. In addition, enhancer/suppressor screen against a hypomorphic ctr1-10 isolated 2 suppressors, ecr1 and ecr2. ecr1 and ecr2 appeared haplo-insufficient and are not allelic, implying that E R1 an ECR2 may coordinate regulate CTR1 activity.
Major Publications:
Gao Z, Wen CK, Binder BM, Chen YF, Chang J, Chiang YH, Kerris III RJ, Chang C, and Schaller GE. (2008) Heteromeric Interactions among Ethylene Receptors Mediate Signaling in Arabidopsis. J. Biol. Chem. 283: 23801-23810. Zhou X, Liu Q, Xie F, and Wen CK. (2007) RTE1 Is a Golgi-Associated and ETR1-Dependent Negative Regulator of Ethylene Responses. Plant Physiology 145: 75-86. Resnick JS, Rivarola M, Wen CK, Shockey JA and Chang C. (2007) A novel membrane protein conserved in plants and animals is important for ethylene receptor function in Arabidopsis thaliana. In: Advances in Plant Ethylene Research, eds. A. Ramina, C. Chang J. Giovannoni, H. Klee, P. Perata, Woltering E. (Springer, Berlin).
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