Ph.D., The Ohio State University
Postdoctoral Research, University of California, Los Angeles (2008-2013)
Lab website: http://zhonglab.genetics.wisc.edu/
Address: Wisconsin Institutes for Discovery, room 2114
Research InterestsWe are interested in understanding the fundamental mechanisms and biological roles of epigenetic modifications of DNA and histones underpinning various biological processes.
Genomics & Proteomics
Computational, Systems & Synthetic Biology
Epigenetic Regulation in Plant Growth and Development
Epigenetic regulation is a process whereby genes can inherit different
states of activity in the absence of any changes in the DNA sequences. One such
epigenetic system involves the addition of a chemical mark on DNA, so-called DNA
methylation, which causes silencing of underlying genes. DNA methylation-based
gene silencing can be very stable and in many cases mitotically heritable. Epigenetic
modifications of histones (proteins that package and organize DNA),
such as methylation and acetylation, play crucial roles in regulating all DNA-dependent processes including
transcription, replication, DNA repair and recombination in diverse organisms. Mis-regulation and abnormalities of histone
modifications are often observed
in plant and animal diseases.
Given the great importance of epigenetic regulation of gene expression in many aspects of biology, ranging from genome integrity, imprinting, cellular differentiation, normal growth and development, disease formation, to potential biotechnological applications, our research goal is to understand the fundamental mechanisms of chromatin-based gene regulation. We study how various chromatin factors are recruited to chromatin to “read” and ‘translate” epigenetic information into differential gene expression patterns under normal growth and development as well as stress conditions. Knowledge gained from such studies should have high and broad impacts on our understanding of how distinct chromatin modifications coordinate with each other to regulate gene expression critical for diverse biological processes. They may also contribute to the development of new tools for applied research.
Some outstanding questions we are interested in answering are:
• How does dynamic epigenetic modification regulate gene expression for proper growth and development?
• How do chromatin alternations lead to changes in stable gene expressions?
• How do different developmental and environmental stimuli influence the chromatin dynamics?
• How are chromatin modifications established and maintained under stress conditions?
• Are altered chromatin structures stable and inheritable?
To address these questions, we use Arabidopsis thaliana as our main experimental model system because of its amenability to genetic manipulations, small genome, availability and viability of most epigenetic mutants. Experimentally, we will use a combination of molecular, genetic, genomic, proteomic, biochemical and structural approaches.
Zhong X (2015) Comparative epigenomics: a powerful tool to understand the evolution of DNA methylation. New Phytologist (In Press)
Zhong X*¶, Hale CJ*, Nguyen M, Ausin I, Groth M, Hetzel J, Vashisht AA, Henderson IR, Wohlschlegel JA, Jacobsen SE¶ (2015) DOMAINS REARRANGED METHYLTRANSFERASE3 controls DNA methylation and regulates RNA polymerase V transcript abundance in Arabidopsis. Proc Natl Acad Sci USA, 112: 911-6. (¶Corresponding author)
Zhong X*, Du J*, Hale CJ, Gallego-Bartolome J, Feng S, Vashisht AA, Chory J, Wohlschlegel JA, Patel DJ, Jacobsen SE (2014) Molecular mechanism of action of plant DRM de novo DNA methyltransferases. Cell, 157: 1050-60.
Yelagandula R, Stroud H, Holec S, Zhou K, Feng S, Zhong X, Muthurajan UM, Nie X, Kawashima T, Groth M, Luger K, Jacobsen SE, Berger F (2014) The histone variant H2A.W marks heterochromatin and promotes chromatin condensation in Arabidopsis. Cell, 158: 98-109.
Johnson LJ, Du J, Hale CJ, Bischof S, Feng S, Chodavarapu RK, Zhong X, Marson G, Pellegrini M, Segal DJ, Patel DJ, Jacobsen SE (2014) SRA- and SET-domain-containing proteins link RNA Polymerase V occupancy to DNA methylation. Nature, 507:124-8.
Stroud H, Do T, Du J, Zhong X, Feng S, Johnson L, Patel DJ, Jacobsen SE (2014) The roles of non-CG methylation in Arabidopsis. Nat Struct & Mol Biol, 21:64-72.
Du J*, Zhong X*, Bernatavichute YV, Stroud H, Feng S, Caro E, Vashisht AA, Terragni J, Chin HG, Tu A, Hetzel J, Wohlschlegel JA, Pradhan S, Patel DJ, Jacobsen SE (2012) Dual binding of chromomethylase domains to H3K9me2-containing nucleosomes directs DNA methylation in plants. Cell, 151: 167-80.
Zhong X*, Hale CJ*, Law JA, Johnson LM, Feng S, Tu A, Jacobsen SE (2012) DDR complex facilitates genome-wide association of RNA polymerase V to promoters and evolutionarily young transposons. Nat Struct & Mol Biol, 19: 870-75.