Poster: Epigenetics & gene silencing

Abs # 828: The nuclear actin-related protein AtARP6 controls flowering time and plant morphology in Arabidopsis

Presenter:	Deal, Roger B, rdeal@arches.uga.edu
Authors	Deal, Roger B (A)   Kandasamy, Muthugapatti K (A)   McKinney, Elizabeth C (A)   Meagher, Richard B (A)
Affiliations:	(A): University of Georgia, Department of Genetics

Members of the actin-related protein (ARP) family perform a wide variety of functions both in the cytoplasm and the nucleus of eukaryotic cells. The cytoplasmic ARPs play well-defined accessory roles within the actin and tubulin cytoskeletal systems, while the functions of the nuclear ARPs are generally understood only on the basis of their enigmatic presence in various chromatin-modifying complexes. Arabidopsis AtARP6 is a clear homolog of ARP6s from fungi and animals, several of which have been implicated in the regulation of chromatin organization. In order to address the function of AtARP6 in Arabidopsis we have examined the subcellular localization, gene expression patterns and loss-of-function phenotype for AtARP6. We find that Arabidopsis AtARP6 is localized to the nucleus and is expressed strongly in the shoot meristem, vascular tissues and, to a lesser extent, in all above-ground tissues. Hypomorphic mutations in AtARP6 result in a multitude of developmental defects including early flowering, altered leaf and flower development, reduced fertility, and increased susceptibility to a fungal pathogen. These results clearly demonstrate that AtARP6 controls multiple aspects of plant development. In light of the nuclear localization of AtARP6 and our knowledge of ARP6s from other organisms, we suggest that this protein likely exerts its effects on plant development through the modulation of chromatin structure.