The long-term objective of this project is to define the epigenome associated with senescence in Arabidopsis thaliana. Non-senescent and senescent leaf tissue will be harvested, and chromatin immunoprecipitation followed by Solexa/Illumina high throughput sequencing (ChIP-SEQ) will be used to define DNA regions that bind to modified histones on a genome-wide scale. Gene expression will also be evaluated on a genome-wide scale by ChIP-SEQ using an antibody that recognizes RNA Polymerase II. Histone modifications to be analyzed include methylations, acetylations and ubiquitinations. Cellular aging in humans is delayed by overexpression of histone deacetylases, and a delayed senescence mutant in Arabidopsis, ore7-1D, was recently shown to result from overexpression of an AT-hook chromatin modifying protein. The epigenome of the ore7-1D mutant will be assessed in Specific Aim 4, which may lead to insights into epigenetic regulation of cellular aging that are shared between plants and humans. Another goal of this pilot proposal is to increase the research competitiveness of the PI via an ongoing mentoring relationship with a successful epigenome researcher at a nearby R01 university.
Epigenetic changes associated with cellular aging will be explored at a genome-wide level in order to gain insight into molecular mechanisms of senescence in Arabidopsis thaliana. In human and plant cells, overexpression of chromatin-modifying enzymes leads to delayed aging, so it is likely that some epigenetic mechanisms are shared among these diverse eukaryotes. Insights into these shared mechanisms are medically relevant for an aging US population.
|Brusslan, Judy A; Rus Alvarez-Canterbury, Ana M; Nair, Nishanth Ulhas et al. (2012) Genome-wide evaluation of histone methylation changes associated with leaf senescence in Arabidopsis. PLoS One 7:e33151|