postdoc position

Postdoctoral Position in the Dept. of Biology, Duke University:

A postdoctoral position (funded by NSF) is available immediately to
study "Regulation of Gibberellin Signaling in Arabidopsis."

Regulation of Gibberellin Signaling in Arabidopsis:

Bioactive gibberellins (GAs) are plant growth regulators, which
control such diverse processes as germination, stem elongation, and
flower and fruit development. The RGA gene encodes a negative
regulator of GA response in Arabidopsis. Several structural
features in the RGA protein suggest that it may be a transcriptional
regulator. In support of this, we showed that a green fluorescent
protein (GFP)-RGA fusion protein is localized to the nucleus in
transgenic Arabidopsis plants. Confocal microscopy and immunoblot
analyses demonstrated that GA activates its signaling pathway by
causing the degradation of the RGA protein, and the DELLA motif near
the N terminus of RGA is required for GA-induced degradation of this
protein. The ubiquitin-proteasome pathway is likely to play a role
in RGA degradation. SLEEPY1 (SLY1), an activator of GA signaling, is
an F-box protein. RGA protein accumulates to a high level in the
sly1 mutant, suggesting that RGA is a target of the SCFSLY1 complex
(an ubiquitin E3 ligase). Using biochemical and genetic
approaches, we are currently investigating the mechanism by which GA
regulates the stability of RGA. We are also using microarray
analysis to identify the downstream targets of RGA.

Related publications:

Silverstone et al. (2001) Repressing a repressor: gibberellin-induced
rapid reduction of the RGA protein in Arabidopsis. Plant Cell 13,
1555-1565.

Dill and Sun (2001) Synergistic derepression of gibberellin signaling
by removing RGA and GAI function in Arabidopsis thaliana. Genetics
159, 777-785.

Dill et al. (2001) The DELLA motif is essential for
gibberellin-induced degradation of RGA. Proc. Natl. Acad. Sci. USA.
98, 14162-14167.

Olszewski et al. (2002) Gibberellin signaling: Biosynthesis,
catabolism and response pathways. Plant Cell Supplement, S61-S80.

McGinnis et al. (2003) The Arabidopsis SLEEPY1 (SLY1) gene encodes a
putative F-box subunit of an SCF E3 ubiquitin ligase. Plant Cell. 15,
1120-1130.


A background in protein chemistry, genetics, molecular biology or
plant development is desirable. If you are interested in applying,
please send (by e-mail) a curriculum vitae and names, e-mail
addresses, and phone numbers of three references to:

Tai-ping Sun
e-mail address: [Only registered users see links. ]

Thanks,
__________________________________________________
Tai-ping Sun
Associate Professor
Department of Biology
LSRC B327, Box 91000
Duke University
Durham, NC 27708-1000
USA

e-mail: [Only registered users see links. ]
TEL: (919)-613-8166
FAX: (919)-613-8177
[Only registered users see links. ]
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