A subset of Arabidopsis AP2 transcription factors mediates cytokinin responses in concert with a two-component pathway

Rashotte, Aaron M., Mason, Michael G., Hutchison, Claire E., Ferreira, Fernando J., Schaller, Eric G. and Kieber, Joseph J. (2006) A subset of Arabidopsis AP2 transcription factors mediates cytokinin responses in concert with a two-component pathway. Proceedings of The National Academy of Sciences of The United States of America, 103 29: 11081-11085. doi:10.1073/pnas.0602038103


Author Rashotte, Aaron M.
Mason, Michael G.
Hutchison, Claire E.
Ferreira, Fernando J.
Schaller, Eric G.
Kieber, Joseph J.
Title A subset of Arabidopsis AP2 transcription factors mediates cytokinin responses in concert with a two-component pathway
Journal name Proceedings of The National Academy of Sciences of The United States of America   Check publisher's open access policy
ISSN 0027-8424
1091-6490
Publication date 2006-07-18
Sub-type Article (original research)
DOI 10.1073/pnas.0602038103
Open Access Status Not Open Access
Volume 103
Issue 29
Start page 11081
End page 11085
Total pages 5
Place of publication Washington
Publisher National Academy of Sciences
Language eng
Subject 06 Biological Sciences
Abstract The plant hormone cytokinin regulates numerous growth and developmental processes. A signal transduction pathway for cytokinin has been elucidated that is similar to bacterial two-component phosphorelays. In Arabidopsis, this pathway is comprised of receptors that are similar to sensor histidine kinases, histidine-containing phosphotransfer proteins, and response regulators (ARRs). There are two classes of response regulators, the type-A ARRs, which act as negative regulators of cytokinin responses, and the type-B ARRs, which are transcription factors that play a positive role in mediating cytokinin-regulated gene expression. Here we show that several closely related members of the Arabidopsis AP2 gene family of unknown function are transcriptionally up-regulated by cytokinin through this pathway, and we have designated these AP2 genes CYTOKININ RESPONSE FACTORS (CRFs). In addition to their transcriptional regulation by cytokinin, the CIRF proteins rapidly accumulate in the nucleus in response to cytokinin, and this relocalization depends on the histidine kinases and the downstream histidine-containing phosphotransfer proteins, but is independent of the ARRs. Analysis of loss-of-function mutations reveals that the CRI's function redundantly to regulate the development of embryos, cotyledons, and leaves. Furthermore, the CRFs mediate a large fraction of the transcriptional response to cytokinin, affecting a set of cytokinin-responsive genes that largely overlaps with type-B ARR targets. These results indicate that the CRF proteins function in tandem with the type-B ARRs to mediate the initial cytokinin response. Thus, the evolutionarily ancient two-component system that is used by cytokinin branches to incorporate a unique family of plant-specific transcription factors.
Keyword Multidisciplinary Sciences
cell signaling
plant hormones
Signal-transduction
Histidine Kinase
Gene-expression
Regulators
Receptor
Thaliana
Shoot
Root
Ahk4
Metabolism
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Biological Sciences Publications
 
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Created: Wed, 19 Sep 2007, 17:00:11 EST