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Timothy
Nelson, Ph.D.
Professor of Molecular,
Cellular & Developmental Biology
Email: timothy.nelson@yale.edu
Room: OML 253A
Phone: (203) 432-3860/ (203) 432-3861
Fax: (203) 432-5632
B.A. University of California,
San Diego 1974; Ph.D. Stanford University
1980 |
Our current work is aimed at understanding the
formation of the regular venation pattern that
appears to guide leaf cell differentiation on
a fine scale. We are identifying the genes and
pathways that form the simple venation pattern
of Arabidopsis leaves, using three experimental
approaches: (1) identification of genes that correspond
to vascular pattern mutants, (2) characterization
of genes with provascular (PV)-specific expression
patterns, and (3) analysis of expression profiles
of PV cells by laser-capture microdissection (LCM)
and microarray analysis. Many pattern defective
mutants have been isolated in Arabidopsis,, including
those with discontinuous or misaligned veins,
open forked veins instead of closed loops, excessive
vascular tissue, vascular islands, or parallel
instead of netted venation. We have cloned several
of the corresponding genes, which are members
of signaling pathways and sterol biosynthetic
pathways. Among genes with PV expression patterns,
we identified a leucine-rich-repeat receptor kinase,
VH1, that influences the differentiation of PV
and neighboring cells. Although its activating
ligand is currently unknown, VH1 interacts in
vivo and in vitro with leaf-specific signaling
partners, and its misexpression or knockout has
developmental consequences in the leaf. In other
studies, we are using LCM for the isolation of
leaf PV cells, whose transient and dispersed existence
during development has made them difficult to
characterize. The resulting PV RNA and protein
expression profiles will be invaluable in deducing
the pathways that produce the patterns of veins.
We are also engaged in preparing a comprehensive
transcriptional profile atlas for all cell types
of the rice plant, utilizing LCM and whole genome
microarrays.
Key Past Publications
Kerk, N., T. Ceserani, S.L. Tausta, I. Sussex
and T. Nelson (2003) Laser-capture microdissection
of cells from plant tissues. Plant Physiol.132.
27-35
Carland, F.M., S. Fujioka, S. Takatsuto, S. Yoshida,
and T. Nelson (2002) The identification of CVP1
reveals a role for sterols in vascular patterning.
Plant Cell 14, 2045-2058.
Clay, N.K., and T. Nelson (2002) VH1: a provascular-specific
receptor kinase that influences leaf cell patterns
in Arabidopsis. Plant Cell 14, 2707-2722.
Publications (2003/2004)
Carland FM, Nelson T. Cotyledon vascular pattern2-mediated
inositol (1,4,5) triphosphate signal transduction
is essential for closed venation patterns of Arabidopsis
foliar organs (2004) Plant Cell. 16,
1263-75. Epub 2004 Apr 20.
Meyers, B.C., D.W. Galbraith, T. Nelson, and
V. Agrawal (2004) Methods for transcriptional
profiling in plants: be fruitful and replicate.
Plant Physiol., 135, 637-652
Teaching
MCDB 105a, An Issues Approach to Biology
MCDB 420b/615b Genetics and Molecular Biology
of Plant Development
Committees and Editorial Boards
Director, Marsh Botanical Garden
NSF grant review panel
Review grant proposals for NSF, DOE and USDA,
and SERC (Canada).
Review manuscripts for Science, Plant Cell, Plant
Physiol., Development, others
Ph.D. committee at Cold Spring Harbor Laboratory
MCDB Building Committee (Chair from 7/04)
Dean's Endowed Postdoctoral Fellowship Selection
committee
Packard Fellowship Selection Committee
Provost's Standing Advisory & Appointments
Committee (FES)
Seminars and Scientific Meetings
Arabidopsis Conference, Madison, WI 19-23 June,
invited speaker
Crowell & Moring LLP, Patent law firm, Washington,
DC, 19 February
Web seminar (150 subscribers) Arcturus laser capture,
25 Sept
NYU Biology, 24 Nov
Agric. Sciences Univ., Bangalore, India, 5 Feb
Interdisc. Plant Program, Univ. Arizona Tucson,
22 March
Yale Rice Symposium, 30 April
CSHL Plant Development Course, invited lecturer,
17 July
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