Wang, Chung-Ju (王中茹)
Associate Research Fellow
- 2020-present: Assoc. Res. Fellow, IPMB, Academia Sinica, Taiwan
- 2018-present, Adjunct Assist./ Assoc. Prof., Graduate Program in Molecular and Environmental Biology, National Central University,
- 2013-present: Adjunct Assist./ Assoc. Prof., Graduate Institute of Life Sciences, National Defense Medical Center, Taiwan.
- 2011-present: Adjunct Assist./ Assoc. Prof., Biotechnology Center, , Taiwan International Graduate Program (TIGP), National Chung Hsing University, Taiwan.
- 2011-2020: Assist. Res. Fellow, IPMB, Academia Sinica
- 2004-2011: PDF, Dept of Mol Cell Biology, UC Berkeley, USA.
- 2003-2004: PDF, IPMB, Academia Sinica.
- 2003 Ph.D. Dept. of Botany, Natl. Taiwan Univ.
- Studies of plant meiosis and anther development.
- Lab Website
Meiosis is a specialized cell division that is essential in reproducing organisms to halve the number of chromosomes, which allows restoration of ploidy during fertilization. In addition, meiosis contributes to genetic variation by creating recombination (i.e. crossovers between paternal and maternal chromosomes). Particularly in crop plants like maize, better understanding of meiotic processes will provide vital insights to plant reproduction and potential applications in plant breeding. We aim to understand mechanisms of meiotic initiation and termination, as well as homologous recombination during meiosis, by a combination of molecular biology, cell biology, super-resolution microscopy, biochemistry and proteomics approaches.
In angiosperms, meiosis takes place in sporogenous cells (germ cells) that develop de novo from somatic cells in anthers or ovules. Later, mitotic cell cycle is switched to the meiotic program. However, the molecular mechanisms of meiotic initiation remain largely unknown. By labeling DNA replication in male germ cells, we unveiled a unique pattern of the mitosis-to-meiosis transition which involves a cell cycle resting stage to synchronize meiosis prior to the pre-meiotic S phase. Our results further indicated that AM1 and MAC1 are required to establish meiotic synchrony and meiotic initiation, respectively. We now focus on transcriptomic and proteomic analyses of isolated meiocytes to identify other players involved in this transition.
In angiosperms, after meiosis is complete, haploid spore exits from meiosis and undergoes mitosis to produce gametophyte (pollen grain and embryo sac). The mechanisms of meiotic exit are poorly understood. We focus on a classical maize mutant (po1), which exhibited additional cell divisions after tetrad stage, resulting in sixteen daughter cells. Our proteomic analysis suggested that PO1 is involved in the ubiquitin-mediated protein degradation pathway.
During meiosis, one of most important processes is homologous recombination, which is required for chromosome pairing and later generates crossovers (COs) to connect homologous chromosomes until their separation at the anaphase I. These CO sites represent reciprocal exchange between paternal and maternal chromosomes, so that reshuffles allelic combinations of a genetic linkage group. This process, taking place only during meiosis, plays an essential role for plant breeding, because a successful breeding program depends on ability to bring the desired combinations of alleles on chromosomes. To understand meiotic recombination, we study the regulation of DNA double-strand-break (DSB) formation, where meiotic recombination is initiated and may give rice to COs. In addition, we identified a chromosome axis protein DSY2 and found its role in promoting DSB formation. By immunoprecipitation using chromosome axis antibodies, we identified important players for DSB formation and their functions are under investigation.
Selected publication list
- Hsu FM, Wang CJR*, Chen PY* (2018). Reduced representation bisulfite sequencing in maize. Bio-Protocol, 8(6):e2778.
- Chang P, Tseng YF, Chen PY*, Wang CJR* (2018). Using flow cytometry to isolate maize meiocytes for next generation sequencing: A time and labor efficient method. Current Protocol of Plant Biology, 3(2):e20068.
- Hsu FM, Yen MR, Wang CT, Lin CY, Wang CJR*, Chen PY* (2017). Optimized reduced representation bisulfite sequencing reveals tissue-specific mCHH islands in maize. Epigenetics and Chromatin, 10:42.
- Lambing C, Franklin FCH, Wang CJR*(2017). Understanding and manipulating meiotic recombination in plants. Plant Physiology, 173:1531-1542.
- Lee DH, Kao YH, Ku JC, Lin CY, Meeley R, Jan YS, Wang CJR*(2015). The axial element protein DESYNAPTIC2 mediates meiotic double-strand break formation and synaptonemal complex assembly in maize. Plant Cell, 27:2519-2529.
- Wang CJR*, Tseng CC (2014). Recent advances in understanding of meiosis initiation and the apomictic pathway in plants. Frontiers in Plant Science, 5, 497:1-6.
- Wang CJR*(2013). Analyzing maize meiotic chromosomes with structured illumination microscopy. Editor(s): Pawlowski WP, Grelon M, Armstrong S, Methods in Molecular Biology, pp 67-78. New York: Springer (Invited book chapter)
- Moon J, Skibbe D, Timofejeva L, Wang CJR, Kelliher T, Kremling K, Walbot V, Cande WZ* (2013). Regulation of cell divisions and differentiation by MALE STERILITY32 is required for anther development in maize. Plant Journal,76:592-602.
- Timofejeva L, Skibbe D, Lee S, Golubovskaya IN, Wang CJR, Harper L, Walbot V, Cande WZ* (2013). Cytological characterization and allelism testing of anther developmental mutants identified in a screen of maize male sterile lines. G3,3:231-249.
- Wang CJR, Nan G, Kelliher T, Timofejeva L, Vernoud V, Golubovskaya IN, Harper L, Egger R, Walbot V, Cande WZ* (2012). Maize Multiple archesporial cells 1 (Mac1), an ortholog of rice TDL1A, modulates cell proliferation and identity in early anther development. Development,139:2594-2603.
- Paredez AR, Assaf ZJ, Sept D, Timofejeva L, Dawson SC, Wang CJR, Cande WZ* (2011). An actin cytoskeleton with evolutionarily conserved functions in the absence of canonical actin-binding proteins. Proc Natl Acad Sci USA, 108:6151-6156.
- Nan GL, Ronceret A, Wang CJR, Fernandes JF, Cande WZ, Walbot V* (2011). Global transcriptome analysis of two ameiotic1 alleles in maize anthers: defining steps in meiotic entry and progression through prophase I. BMC Plant Biology,11:120.
- Golubovskaya IN, Wang CJR, Timofejeva L, Cande WZ* (2011). Maize meiotic mutants with improper or nonhomologous synapsis due to problems in pairing or synaptonemal complex formation. Journal of experimental botany, 62:1533-1544. (The first two authors contributed equally to this work) (Journal cover).