Award Abstract #0114965
Arabidopsis 2010: Analysis of Two-Component Signaling Elements from Arabidopsis

NSF Org:	IOS Division of Integrative Organismal Systems
Initial Amendment Date:	August 13, 2001
Latest Amendment Date:	March 23, 2005
Award Number:	0114965
Award Instrument:	Continuing grant
Program Manager:	Jo Ann Banks IOS Division of Integrative Organismal Systems BIO Directorate for Biological Sciences
Start Date:	September 1, 2001
Expires:	August 31, 2006 (Estimated)
Awarded Amount to Date:	$2118000
Investigator(s):	Joseph Kieber jkieber@unc.edu (Principal Investigator) Estelle Hrabak (Co-Principal Investigator) George Schaller (Co-Principal Investigator) Robert Pope (Co-Principal Investigator)
Sponsor:	University of North Carolina at Chapel Hill 104 AIRPORT DR STE 2200 CHAPEL HILL, NC 27599 919/966-3411
NSF Program(s):	DEVELOPMENTAL BIOLOGY CLUSTER, PLANT FUNGAL & MICROB DEV MECH
Field Application(s):	0000099 Other Applications NEC
Program Reference Code(s):	SMET, BIOT, 9251, 9183, 9178, 9109, 1684, 1111
Program Element Code(s):	7471, 1118

ABSTRACT



Two-component systems are the primary means by which bacteria sense and respond to environmental stimuli. These systems are comprised of a number of distinct elements, namely histidine kinases, response regulators and in the case of phosphorelays, histidine phosphotransfer proteins (HPts). Genes encoding similar proteins to each of these elements have been identified in Arabidopsis, and for the majority of the 35 such genes no function has yet been definitively ascribed. An integrated approach to elucidate the function of these proteins in Arabidopsis is proposed. A combination of gene knockouts and inducible overexpression will be used to assess the roles of these genes in plant growth and development. The mutant plant lines will be characterized in terms of their response to biotic and abiotic factors such as hormones, light, and osmotic stress, and for their pattern of gene expression. Where in the plants these genes are expressed will be determined using a combination of GUS fusions and in situ RNA analysis. The location of the cognate proteins within the cell will also be delineated. To facilitate this localization, a series of 10 monoclonal antibodies will be generated to marker proteins, each of which resides on a distinct membrane. Protein complexes from Arabidopsis will be purified and analyzed to determine the interactions among these elements and to identify novel interacting proteins. Together, these studies will illuminate the signaling pathways in which each of these Arabidopsis two-component signaling elements function and how they interact to control plant growth and development.

The data from these studies will be deposited on a publicly accessible web page that is currently under construction at UNC (http://www.bio.unc.edu/research/two-component/). A link to this web site will be established on the TAIR database, and we will coordinate with TAIR to deposit data as appropriate. The knockout seeds will be made publicly available through deposition in the ABRC Stock Center at Ohio State. The monoclonals raised against the membrane marker proteins will be available for the cost of shipping through UNH and the cell lines will also be deposited with the American Type Culture Collection (ATCC).

In keeping with the goals of the 2010 project, functional analysis of the two-component signaling elements will aid in our understanding of plants at the organismal, cellular, and evolutionary levels. The research will provide functional information on the role of Arabidopsis two-component signaling systems in plant growth and development. The research will serve to define the subcellular location of the two-component signal transduction pathways, the interactions between the two-component signaling elements, and the downstream targets of the pathways. The research should clarify how a signal transduction mechanism that arose in bacteria has been adapted to plant signal transduction.

These studies should uncover the functions of several gene families in Arabidopsis. The proteins encoded by these gene families are predicted to interact and thus our studies should aid in the development of a paradigm for signaling specificity among interacting members of large gene families. In addition, tools will be developed that will be generally applicable in defining the subcellular location of proteins in Arabidopsis.

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