DNA demethylation in maize endosperm gene regulation

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In addition to embryos, seeds contain endosperm, which is similar to the placenta in that it is a separate product of fertilization that provides nutrition to the embryo. Endosperm is different from other plant organs not only in terms of genetics, but also epigenetics. In particular, genes with identical DNA sequences in endosperm produce different physical traits depending on whether they were inherited maternally or paternally. The goal of this project is to understand how DNA is modified in endosperm to cause genes to be regulated in this way. Endosperm is the major source of calories for human consumption, so understanding how genes are regulated in endosperm is important for agricultural science. While the project will focus on maize (corn), one of the most important food crops in the world, fundamental principles of endosperm gene regulation discovered through this work will also apply to other plants. The project will also include an outreach component to elementary school students and teachers to encourage biology career paths and to educate on scientific methods.In plants, DNA is demethylated by DNA glycosylases. Endosperm is distinguished from other tissues by activity of specific DNA glycosylases at thousands of genomic loci, as evidenced primarily by work in the model plant Arabidopsis thaliana. This project will build on this foundation, but with research on maize because of its experimental advantages and the agricultural importance of its endosperm. The goals are to use RNA, chromatin, and methylation sequencing methods in glycosylase mutant and wild-type endosperm to determine what genomic features recruit glycosylases and how their demethylation affects chromatin structure and transcription. In addition, the data generated from these experiments will be used to design synthetic gene expression modules for testing the resulting predictions and for controlling gene expression in endosperm.This project is jointly funded by the Genetic Mechanisms program in the Division of Molecular and Cellular Biosciences and the Plant Genome Research Program in the Division of Integrative Organismal Systems of the Biological Sciences Directorate.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.