The main focus of Dr. Sunter’s research is directed toward the study of plant gene expression, DNA replication, and plant-pathogen interactions using single-stranded DNA plant viruses of the family Geminiviridae as a model system. One aspect of the research involves transcriptional regulation. In many viral systems, gene expression follows a temporal sequence that is closely coordinated and during the initial stages of infection viral DNA replication and transcription rely entirely on the host and in many cases some of the viral proteins initially expressed are subsequently involved in the regulation of other viral genes. Dr. Sunter is particularly interested in two viral genes that are involved in replication and transcription of the viral genome. The coordinate regulation of these genes appears crucial to ensure correct timing of both replication and transcription and may well reveal novel mechanisms and insights into plant transcription mechanisms.
A second interest involves the role of viral genes in host gene activation. Geminiviruses rely primarily on host replication and transcriptional machinery to express their genes and amplify their genomic DNA. To overcome the inherent inability of plant cells to replicate viral DNA, geminiviruses must in some way make cells receptive to replication and transcription of the virus. In animals, many DNA viruses are capable of altering the host cell to facilitate efficient replication and transcription of viral DNA, either by direct activation of host gene expression or by interacting with cellular transcription factors. These interactions in turn induce expression of genes encoding proteins required for DNA replication and cell cycle progression. Dr. Sunter is interested in identifying cellular genes activated and/or repressed by the virus and elucidating mechanisms by which the virus interacts with these proteins.