REU: Collaborative Research: CPSF30 at the Convergence of RNA Processing, Cellular Signaling, and Development in Plants

The posttranscriptional control of gene expression makes important contributions to the overall growth and development of plants, and to the interactions of plants with their environment. However, much remains to be learned regarding the mechanisms by which developmental and environmental stimuli impact gene expression at the posttranscriptionallevel. The focus of this project is a gene that encodes proteins that have been linked with both cellular signaling mechanisms and pre-mRNA processing by our laboratories. Specifically, we have recently demonstrated an unprecedented link between calcium signaling and mRNA polyadenylation. This gene, At1g30460 or OXT6, encodes a polyadenylation factor subunit (AtCPSF30) that has been shown to be regulated in vitro by calmodulin. Interestingly, it also encodes an additional protein (At30*Y) that may be involved in other modes of regulation. Mutants deficient in the expression of this gene display a number of phenotypes, including altered hormonal responses and root growth, indicating that its products play roles in several growth and developmental processes. The hypothesis that guides this research holds that OXT6-mediated regulation of growth and development is accomplished by the recognition of target RNAs by the OXT6 gene products, leading to changes in mRNA polyadenylation and gene expression The long-term goal of research is to understand the role of gene expression regulation through mRNA polyadenylation. The goals of this project are to dissect the links between pre-mRNA processing, cellular signaling, and the phenotypic consequences of mutation in these two proteins, AtCPSF30 and AtC30*Y. This will be accomplished by pursuit of the following specific aims: 1. To test the hypothesis that the interaction with calmodulin is needed for all of the phenotypes associated with AtCPSF30. 2. To test the hypothesis that AtC30*Y can replace AtCPSF30 in its functioning, and that the interaction of AtC30*Y with calmodulin is important in these roles. 3. To test the hypothesis that the OXT6-encoded proteins mediate alternative polyadenylation on a genome-wide scale, and that some of these events involve significant alterations of the expression of the putative target genes.