Z. Renee Sung

Job title:

Professor Emeritus

Bio/CV:

Education

Ph.D. Plant Physiology University of California, Berkeley
B.S. Botany National Taiwan University

About the Lab

The Sung laboratory investigates the mechanism that represses flowering and seed development, whereby enabling vegetative growth and expanding life span. We focus on the epigenetic mechanism that regulates the flowering and seed development genes by the Polycomb Group (PcG) and trithorax Group (trxG) protein complexes. We also take a phylogenetic approach to study the origin and evolution of the PcG genes, as well as their function in early emerging plants. The long term goal is to understand their contribution in the evolution of plant development and generation of diverse morphology.

Research

Epigenetic regulation of plant development

Research in the Sung laboratory is focused on the regulation of gene function at the chromatin level in plants. Polycomb group (PcG) and trithorax group (trxG) proteins play evolutionarily conserved roles in the epigenetic regulation of gene expression. The mutually antagonistic activities of PcG and trxG proteins promote the stable and maintenance of repressed and active transcriptional states, respectively, via histone modification on the target gene sequences. Despite the general view and advances in studies of the PcG and trxG proteins, we still know little about how PcG function relates to that of the trxG. We are studying a plant-specific gene, EMBRYONIC FLOWER 1 (EMF1), encoding an transcriptional regulator involved in plant PcG-mediated gene repression mechanism. Genome-wide investigation of EMF1 targets showed that EMF1 regulates the expression of a large number of transcription factor genes, including flower and seed genes, via diverse mechanisms. Tissue-specific removal of EMF1 activity from leaf primordia leads to early flowering plants with curly leaves that can be counteracted by mutations in ULTRAPETALA1 (ULT1). Thus ULT1 functions as a trxG factor antagonizing PcG action on flowering. ult1 mutation counteracting early flowering is accompanied by restoration of the reduced trimethylation of Histone3 lysine 27 on flower MADS box genes in the emf mutants. We are studying PcG and trxG functions and molecular mechanism of their activities. Recent studies revealed unexpected observation that contrary to PcG and trxG antagonistic action on flower genes, trxG can compensate the loss of EMF1 function in maintaining seed gene repression during germination. A current goal is to characterize this novel compensatory mechanism by the trxG factors and how they play opposite role in regulating seed development and flowering, two important traits in agriculture.

Recent Publications

Pu, L., and Sung, Z.R. (2015). PcG and trxG in plants - friends or foes. Trends Genet 31, 252-262.

Chen, X., Qi, Y., and Sung, Z.R. (2014). Special issue on plant epigenetics. Mol Plant 7, 453.

Pu, L., Liu, M.S., Kim, S.Y., Chen, L.F., Fletcher, J.C., and Sung, Z.R. (2013). EMBRYONIC FLOWER1 and ULTRAPETALA1 Act Antagonistically on Arabidopsis Development and Stress Response. Plant Physiol 162, 812-830.

Kim, S.Y., Lee, J., Eshed-Williams, L., Zilberman, D., and Sung, Z.R. (2012). EMF1 and PRC2 Cooperate to Repress Key Regulators of Arabidopsis Development. PLoS Genet 8, e1002512.

Liu, M.S., Chen, L.F., Lin, C.H., Lai, Y.M., Huang, J.Y., and Sung, Z.R. (2012). Molecular and functional characterization of broccoli EMBRYONIC FLOWER 2 genes. Plant Cell Physiol 53, 1217-1231.

Park, H.Y., Lee, S.Y., Seok, H.Y., Kim, S.H., Sung, Z.R., and Moon, Y.H. (2011). EMF1 interacts with EIP1, EIP6 or EIP9 involved in the regulation of flowering time in Arabidopsis. Plant Cell Physiol 52, 1376-1388.

Kim, S.Y., Zhu, T., and Sung, Z.R. (2010). Epigenetic regulation of gene programs by EMF1 and EMF2 in Arabidopsis. Plant Physiol 152, 516-528.

Chen, L.J., Diao, Z.Y., Specht, C., and Sung, Z.R. (2009). Molecular evolution of VEF-domain-containing PcG genes in plants. Mol Plant 2, 738-754.

Sanchez, R., Kim, M.Y., Calonje, M., Moon, Y.H., and Sung, Z.R. (2009). Temporal and Spatial Requirement of EMF1 Activity for Arabidopsis Vegetative and Reproductive Development. Molecular Plant 2, 643-653.

Calonje, M., Sanchez, R., Chen, L., and Sung, Z.R. (2008). EMBRYONIC FLOWER1 participates in polycomb group-mediated AG gene silencing in Arabidopsis. Plant Cell 20, 277-291.

Sanchez-Pulido, L., Devos, D., Sung, Z.R., and Calonje, M. (2008). RAWUL: A new ubiquitin-like domain in PRC1 ring finger proteins that unveils putative plant and worm PRC1 orthologs. Bmc Genomics 9.

Calonje, M., and Sung, Z.R. (2006). Complexity beneath the silence. Current Opinion in Plant Biology 9, 530-537.

Chanvivattana, Y., Bishopp, A., Schubert, D., Stock, C., Moon, Y.H., Sung, Z.R., and Goodrich, J. (2004). Interaction of Polycomb-group proteins controlling flowering in Arabidopsis. Development 131, 5263-5276.

Henderson, J.T., Li, H.C., Rider, S.D., Mordhorst, A.P., Romero-Severson, J., Cheng, J.C., Robey, J., Sung, Z.R., de Vries, S.C., and Ogas, J. (2004). PICKLE acts throughout the plant to repress expression of embryonic traits and may play a role in gibberellin-dependent responses. Plant Physiol 134, 995-1005.

Lertpiriyapong, K., and Sung, Z.R. (2003). The elongation defective1 mutant of Arabidopsis is impaired in the gene encoding a serine-rich secreted protein. Plant Mol Biol 53, 581-595.

Moon, Y.H., Chen, L., Pan, R.L., Chang, H.S., Zhu, T., Maffeo, D.M., and Sung, Z.R. (2003). EMF genes maintain vegetative development by repressing the flower program in Arabidopsis. Plant Cell 15, 681-693.

Sung, Z.R., Chen, L., Moon, Y.H., and Lertpiriyapong, K. (2003). Mechanisms of floral repression in Arabidopsis. Curr Opin Plant Biol 6, 29-35.

Avsian-Kretchmer, O., Cheng, J.C., Chen, L., Moctezuma, E., and Sung, Z.R. (2002). Indole acetic acid distribution coincides with vascular differentiation pattern during Arabidopsis leaf ontogeny. Plant Physiol 130, 199-209.

Yoshida, N., Yanai, Y., Chen, L.J., Kato, Y., Hiratsuka, J., Miwa, T., Sung, Z.R., and Takahashi, S. (2001). EMBRYONIC FLOWER2, a novel polycomb group protein homolog, mediates shoot development and flowering in Arabidopsis. Plant Cell 13, 2471-2481.

Aubert, D., Chen, L.J., Moon, Y.H., Martin, D., Castle, L.A., Yang, C.H., and Sung, Z.R. (2001). EMF1, a novel protein involved in the control of shoot architecture and flowering in Arabidopsis. Plant Cell 13, 1865-1875.

Bai, S., Chen, L., Yund, M.A., and Sung, Z.R. (2000). Mechanisms of plant embryo development. Curr Top Dev Biol 50, 61-88.

Cheng, J.C., Lertpiriyapong, K., Wang, S., and Sung, Z.R. (2000). The role of the Arabidopsis ELD1 gene in cell development and photomorphogenesis in darkness. Plant Physiol 123, 509-520.

Vernoux, T., Wilson, R.C., Seeley, K.A., Reichheld, J.P., Muroy, S., Brown, S., Maughan, S.C., Cobbett, C.S., Van Montagu, M., Inze, D., May, M.J., and Sung, Z.R. (2000). The ROOT MERISTEMLESS1/CADMIUM SENSITIVE2 gene defines a glutathione-dependent pathway involved in initiation and maintenance of cell division during postembryonic root development. Plant Cell 12, 97-110.

Recent Teaching

24 - Freshman Seminar
150L - Laboratory for Plant Cell Biology
150 - Plant Cell Biology
192C - Biological Sciences
199 - Supervised Independent Study

Research interests:

Plant Growth and Development

Role:

Plant Biology

Emeriti