Ho

• Ph.D. in Biology at Michigan State University

1) Hormonal control of gene expression in the aleurone cells of cereal grains. We study the mechanisms and signal transduction pathways regulating the expression of genes encoding a-amylases and proteases. We have defined the promoter elements which are necessary and sufficient for hormonal regulation, and are currently studying the trans-acting factors interacting with these promoter sequences. We are also interested in understanding the molecular basis for the GA/ABA antagonism. The role of a protein phosphatase 2C and a serine/threonine protein kinase in mediating the ABA signal transduction pathways is currently under investigation.

2) Regulation and function of stress-induced genes. Our efforts are centered around three stress proteins originally isolated from cereal plants: a nuclear encoded, chloroplast-localized heat shock protein; a drought stress/ABA-induced protein with amphipathic a-helical structures, and a drought/ABA-induced protein with apparent homologs present in all eukaryotes. We are investigating the function of these proteins as well as the mechanisms regulating their synthesis. Homologs of these proteins in yeast and Arabidopsis are being investigated following both genetic and biochemical approaches to address several key questions: How is the stress signal perceived by the cells? How are the genes encoding stress proteins induced by the perceived signal? Can these stress proteins protect cells from being injured by stressful conditions?