Transcriptional Adaptors and Histone Acetyltransferases in Arabidopsis Gene Expression

Michigan State University, East Lansing MI

Investigators

Abstract

Transcriptional adaptor or coactivator proteins play central integrating roles in regulating eukaryotic gene expression. These proteins function in part to overcome the barrier to transcription imposed by the packaging of eukaryotic genomes in the form of chromatin. The ADA2 and GCN5 proteins are two components of multiprotein coactivator complexes. The biological roles of these coactivator proteins are largely unknown in plants, but the available evidence suggests significant differences from the corresponding mechanisms in yeast and animals. Therefore, the long-term goal of this research project is to define the roles of transcriptional adaptor proteins in regulating gene expression in plants. The mustard cress Arabidopsis is used extensively as a model organism for genetic and molecular biological studies in plants. The genome of Arabidopsis encodes two ADA2 proteins and one GCN5 protein, each with some features in common with yeast and animal homologs and other features unique to plants. Mutations in the ADA2b and GCN5 genes have similar and also distinct effects on plant growth and development, suggesting that the corresponding proteins have both common and distinct biological functions. This project will characterize plant-specific features of these adaptor proteins using genetic and molecular genetic approaches. To identify features of GCN5 or ADA2 proteins that are required for biological activity, specific mutations will be tested for the ability to complement existing gcn5 or ada2 T-DNA disruption mutations. The distinct biological roles of the two ADA2 genes (ADA2a and ADA2b) will be defined by identifying tissue- or cell-specific expression patterns, and by domain-swap experiments. Similar genes from important crop and experimental plants will be characterized to lay the foundation for future genetic and biochemical investigations. This project will fill an important gap in the understanding of the diversity of genetic regulatory mechanisms and may be valuable in future agricultural or biotechnological applications. In addition, this project provides training opportunities specifically tailored for undergraduate, graduate and postdoctoral scientists.