In order for multicellular organisms to grow into their final size and shape, precise control mechanisms must regulate the number of cell division cycles and coordinate growth with differentiation. This project investigates how a gene named TSO1 controls and coordinates these processes in a flowering plant, Arabidopsis thaliana. As animals and plants exhibit significant differences in their development and ability to regenerate, they may possess different mechanisms for regulating and coordinating growth with differentiation. Investigation of TSO1 function will provide further insights into these processes and the key differences between animals and plants. Based on the tso1 mutant phenotype, TSO1 is hypothesized to be a key integrator of cell cycle control with organogenesis and differentiation in plants. The sequence similarity between TSO1 and the animal Mip120/LIN54 proteins suggests that TSO1 may act in a chromatin complex to affect chromatin assembly, DNA replication, and transcription programs. The project will first identify genes directly regulated by TSO1 using genomic approaches. Genetic analysis will then be used to characterize a selective set of target genes and pathways. Additionally, three proteins, AtRBR, AtALY, and AtMSI1, whose counterparts are known to act in similar processes in animals, will be tested for their direct interactions with TSO1. A mutagenesis screen will be conducted to identify other TSO1-interacting proteins.
Broader impacts: In addition to identifying novel mechanisms that may underlie the significant plasticity in the growth and development of plants, the project provides training in genomics and genetics to a postdoctoral fellow, a PhD student, several undergraduate students from under-represented backgrounds, as well as high school students. The postdoctoral fellow will follow a career development plan that encourages independent thinking, development of communication skills, and student mentoring. The scientists in the project will continue participating in the "lunch with a scientist" program at a local elementary school. The activities will impact students at multiple levels and from diverse backgrounds. Finally, due to the conservation in genes and their regulatory mechanisms between Arabidopsis and other plant species, knowledge gained from studying Arabidopsis can be applied to other plant species including crop plants to improve crop yields.
