Genetic, molecular, and biochemical analysis of RNA splicing factors critical for maize endosperm development

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This project will investigate how plants process RNA to influence maize grain composition and quality. All organisms express genes by transcribing their DNA into RNA, with most RNA molecules getting translated into protein. In plants, animals, and fungi, genes that code for proteins typically have a modular structure made up of exons, which are needed to express a protein, and introns, which need to be removed by RNA splicing factors. This project will examine the role of four RNA splicing factors in removing introns from genes needed to develop a maize kernel. The research will integrate genetic, molecular, genomic, and biochemical approaches to define functional networks of genes influenced by these splicing factors and may identify genes that could be used to improve seed set or grain-fill in crop plants. The project will train graduate and undergraduate students in biological research through multiple activities aimed at helping the students to develop into professional scientists. Splicing of pre-mRNA is critical to expressing genes as phenotypes. However, the molecular mechanisms by which plant RNA splicing factors influence splice site selection and how alternative splicing influences plant phenotypes are largely unknown. There are significant gaps in knowledge about the target introns for individual splicing factors. It is not known how individual splicing factors influence splicing decisions to control the proteome and, ultimately, the phenotype of the plant. This project will focus on splicing factors with strong evidence for functional importance in maize seed development. RNA splicing events required for seed development will be identified in splicing factor mutants that cause seed defects. Reverse genetics analysis will determine the roles of a plant-specific putative splicing SR protein known to be expressed in seeds. Cell-type specific and direct targets of two RNA splicing factors critical to the maize endosperm will be identified. Integrating the data from the aims will elucidate mechanisms by which individual RNA splicing factors influence gene expression to differentiate endosperm cell types and ultimately influence multicellular phenotypes. Because seeds are the primary product of maize crops, understanding RNA splicing in seed development will both advance fundamental molecular biology and identify pathways and proteins for future crop improvement. This award is co-funded by the Genetic Mechanisms Program in the Division of Molecular and Cellular Biosciences and by the Plant Genome Research Program in the Division of Integrative Organismal Systems, both in the Directorate for Biological Sciences.