postdoc position

Erin Connolly erinc at
Thu Jun 21 09:46:55 EST 2001

University of South Carolina
Columbia, South Carolina

A postdoctoral research position is available immediately to study the
regulation of metal uptake in Arabidopsis.  We are studying the
regulation of a ferrous iron transporter, IRT1 (Iron-Regulated
Transporter).  IRT1 encodes an integral membrane protein that belongs to
the ZIP family of metal transporters.  IRT1 is known to transport zinc,
manganese and cadmium, in addition to iron.  Transgenic plants
engineered to overexpress IRT1 (35S-IRT1) revealed that IRT1 is subject
to post-transcriptional regulation by iron and zinc.  Experiments in
yeast suggest that this control is implemented post-translationally via
regulated endocytosis in response to high metal levels. The yeast high
affinity zinc transporter, ZRT1, another ZIP family member, has been
shown to be subject to ubiquitination and endocytosis following
treatment with high concentrations of zinc (Gitan and Eide, Biochem 
J. 346:329-336).

35S-IRT1 plants show an enhanced sensitivity to cadmium under
iron-deficiency conditions, presumably due to elevated levels of IRT1
protein in iron-deficient roots.  The enhanced sensitivity of the
35S-IRT1 plants to cadmium has allowed the identification of cadmium
resistant mutants (scs for suppressor of cadmium sensitivity).  Several
of the mutants display alterations in IRT1 protein accumulation and
presumably define factors involved in the regulation of IRT1
accumulation.  Projects currently underway include 1) map-based cloning
of genes identified by the scs mutations, 2) characterization of the
role of ubiquitination in the turnover of IRT1 and 3) identification of
amino acid residues of IRT1 that are necessary for post-translational
regulation.   A thorough understanding of the regulation of transporter
expression will be essential for the creation of food crops with
enhanced nutrient content and for the creation of crops that can
accumulate toxic metals in aid of phytoremediation.

A background in molecular biology and genetics is required. Interested
candidates should send a cover letter, CV, reprints or preprints and the
names, addresses and FAX numbers of three references to Erin Connolly,
Department of Biological Sciences, Coker Life Science Bldg., University
of South Carolina, Columbia, SC 29208. Telephone (803) 777-8753; FAX
(803) 777-4002.  Email applications/inquiries are also welcome
(erinc at  I will be available at the upcoming Arabidopsis
meeting to discuss possible projects.

The Biology Department at the University of South Carolina has a growing
group of plant molecular biologists including Beth Krizek (the role of
ANT in flower development), Vicki Vance (post-transcriptional gene
silencing), Johannes Stratmann (signal transduction in plant defense
responses), Laszlo Marton (phytoremediation) and Lew Bowman (RNA binding
proteins and post-transcriptional gene silencing).  Columbia is a
growing city in the center of South Carolina, approximately 1.5 hours
from beautiful beaches and 2 hours from the Blue Ridge Mountains.

Erin L. Connolly
Assistant Professor
Department of Biological Sciences
University of South Carolina
Columbia, SC 29208

phone: (803) 777-8753
fax: (803) 777-4002


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