Post-doc position at UCLA and IACR-Long Ashton

Andy Phillips andy.phillips at bbsrc.ac.uk
Wed Mar 11 10:32:47 EST 1998


A Postdoctoral Research Fellowship is available at University of
California, Los Angeles (UCLA) and IACR-Long Ashton Research Station,
University of Bristol, UK.

The gibberellins (GAs) are diterpenoid hormones that are involved in all
aspects of plant development, including stem extension, leaf expansion,
flower development, fruit-set and expansion, and seed germination. 
Their biosynthesis, which is strictly regulated in plant tissues,  is
highly complex and involves the action of cyclases, cytochrome
P450-dependent mono-oxygenases and 2-oxoglutarate-dependent dioxygenases
(Hedden, P. and Kamiya, Y. 1997. Annu. Rev. Plant Physiol. Plant Mol.
Biol. 48, 431-460).  Genes encoding some of these enzymes have been
cloned from several species.  Dwarf mutants, in which there is a lesion
in the GA-biosynthetic pathway, are known for many species, including
maize, for which at least four GA-deficient mutants have been described
(Phinney, B.O. 1984. In: The Biosynthesis and Metabolism of Plant
Hormones, Society for Experimental Biology Seminar series 23, edited by
Crozier, A. and Hillman, J.R., eds., pp. 17-41. Cambridge University
Press, Cambridge).  A major aim of this project, which is a
collaboration between Professor B.O. Phinney, Department of Biology,
UCLA, Los Angeles, USA and Dr Peter Hedden, IACR-Long Ashton Research
Station, Bristol, UK, is to clone GA-biosynthesis genes from maize; the
major targets are ent-kaurene synthase and GA 3beta-hydroxylase, which
are thought to be the sites of the genetic lesions in the dwarf-5 and
dwarf-1 mutants, respectively.    As well as defining these mutations,
the availability of the clones will provide the enzymes, by heterologous
expression, for studies on function and will lay the groundwork for
genetic manipulation of GA biosynthesis in maize.  Homologues of the
target genes are available from other species and will aid in their
cloning.
        A second aim is to isolate genes that are involved in GA
perception or signal transduction in transposon-tagged dwarf mutants of
maize with altered responsiveness to GA.  One such line is currently
being
characterised. It has been shown to contain elevated levels of GAs
indicating that the lesion is closely associated with GA signalling.
        The position is initially for one year, renewable up to three
years. It will be funded from, and based at, UCLA.  It is anticipated
that the appointee will spend approximately 50% of their time at each
site: funds are available for 1-2 flights per year between the two
sites.
        For further information, please contact Prof. B.O. Phinney
(bop at ucla.edu; phone/fax (+1)-310-825-3177) or Dr. P. Hedden
(peter.hedden at bbsrc.ac.uk; phone (+44)-1275-549263; fax
(+44)-1275-394281) as soon as possible.

------------------------------------------------------------------------ 
 Email : andy.phillips at bbsrc.ac.uk  : University of Bristol           
 Phone : +44-1275-549257            : IACR Long Ashton Research Station 
 Fax   : +44-1275-394281            : Long Ashton, Bristol, BS18 9AF, UK 
 WWW   : http://www.lars.bbsrc.ac.uk/plantsci/molbiol/molbiol.html

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