This project is focused on the changes in chromatin structure that result from the phosphorylation of specific sites on histone H2A molecules in higher plants. Changes in histone H1 and H2B phosphorylation are known to alter histone binding to DNA in animal cells, and, as a consequence, the resultant chromatin structure. It is reasonable to suspect that the phosphorylation of multiple SPKK motifs near the C-terminus of wheat chromatin H2A histone may alter chromatin structure by neutralizing large, highly basic regions of the protein. The experimental plan will provide information on the levels of H2A phosphorylation at various stages of the cell cycle and test whether the SPKK motif serves as a substrate for the M- phase protein kinase known as p34cdc2. A series of reconstitution experiments will show how histone H2A, at various levels of phosphorylation, affects DNA binding and chromatin structure in higher plants. %%% Changes in chromatin structure are widely viewed as being extremely important during periods of gene expression, and at specific points during the cell cycle when chromosomes condense and decondense. This project is focused on how the phosphorylation of specific motifs present in the histone H2A molecule change during the cell cycle in higher plants and how this change in histone charge affects DNA binding and resultant chromatin structure.
