Poster: Photomorphogenesis

Abs # 388: Light- and auxin-regulated protein kinases from Arabidopsis thaliana

Presenter:	Santner, Aaron A., asantner@iupui.edu
Authors	Santner, Aaron A. (A)   Watson, John C. (A)
Affiliations:	(A): IUPUI, Department of Biology

The PK3At1 and PK3At2 genes of Arabidopsis encode presumptive protein-serine/threonine kinases whose catalytic domains are closely related to the second messenger-dependent kinases. The goal of our research is to determine what roles PK3At1 and PK3At2 play in plant development. Here we demonstrate that the transcript accumulation of PK3At1 and PK3At2 is regulated by both light and auxin perception. PK3At1 and PK3At2 each contain a potential bipartite nuclear localization signal within their C-terminal domains. To determine if these proteins were localized to nuclei, we constructed in-frame fusions between PK3At1 or PK3At2 and GFP. These constructs and the vector were introduced separately into onion epidermal cells by particle bombardment. The results of these experiments suggest that both PK3At1 and PK3At2 are located in the nucleus, although not exclusively. A search of the SIGnAL database of T-DNA flanking regions revealed three individual lines that have T-DNA insertions in the coding region of PK3At1 and one line with an insertion in the coding region of PK3At2. These lines have been obtained and screened for individuals that are homozygous for the T-DNA insertion. We identified plants that were homozygous for the T-DNA insertion in lines pk3at1-1, pk3at1-3, and pk3at2-1. The homozygotes were carefully analyzed for phenotypic irregularities but none were found. Therefore, we have crossed the homozygous mutant lines with the goal of disrupting both PK3At1 and PK3At2 in a single plant. Supported by USDA grant no. 2002-35304-12305.