Poster: Signaling, cell-to-cell

Abs # 424: Dissecting the function(s) of CLE gene family in Arabidopsis

Presenter:	Sharma, Vijay K, Vsharma@berkeley.edu
Authors	Sharma, Vijay K (A)   Baker, Catherine  (B)   Fletcher, Jennifer C (A)
Affiliations:	(A): Plant Gene Expression Center, University of California, Berkeley (B): Department of Biology, Caltech, Pasadena, California

A balanced programming of stem cell divisions and differentiation of progeny cells are critical to maintain functional plant meristems. As plants grow, they coordinate their development and environmental responses by exchanging information using small gene products called signaling molecules. Several mutants have been isolated with defect in maintaining stem cell population in shoot apical meristem. We have identified a plant specific family of CLV3/ESR like (CLE) genes encoding small putative signaling molecules from Arabidopsis and other plants. CLAVATA3 (CLV3) founder member of CLE gene family encodes for a small signaling protein, communicating information between cells at the growing shoot tips of plants, but the functions of the other CLE signaling molecules are unknown. CLV3 acts as a ligand for CLV1, a leucine rich receptor kinase (LRRK), there are more than 200 LRRK in Arabidopsis. Only for a few LRRKs there are evidence for ligands but majority of these LRRK are orphans. We are analyzing the functions for each of the member of this family. For some of these genes we have shown that they are secreted and could be potential ligands (Sharma et al. 2003, PMB 51:415-425). Over-expression under 35S promoter for few of them resulted in 35S::CLV3 like phenotype suggesting they could function in a similar fashion. Further expression analysis by in situ and promoter GUS for all members is in progress and we have very interesting results for some of them indicating their involvement in plant development. We have generated antisense lines for all of them and have also identified knockout T-DNA mutants. Further characterization of these genes for their role in plant development is in progress and details would be discussed in the conference.