• Meiotic cell-cycle control
• Molecular mechanisms of pachytene checkpoint

Meiosis plays a crucial role in sexual reproduction of eukaryotes. It consists of one round of DNA replication and two successive nuclear divisions to reduce the numbers of chromosomes in gametes. Therefore, after fertilization, the numbers of chromosomes in offspring cells are remained constant. The key events of meiosis are the paring and crossing-over of homologous chromosomes in the prophase, as well as their separation in meiosis I. To ensure the success the progression of meiosis are under strict controls of checkpoints, especially the pachytene checkpoint.

How can meiotic cells proceed through two nuclear divisions successively without re-replicating DNA in-between? How do checkpoints detect the errors and control the meiotic cell cycle? The molecular mechanisms of these two questions are our primary research topics. We use the budding yeast, Saccharomyces cerevisiae, as the model system for our study. Though single-celled as budding yeast is, the advantages of easy-to-culture and the well-established research systems have made it an important model in modern molecular genetics. In 1996, the DNA sequencing of budding yeast is completed. And most importantly, meiosis could be synchronously induced in budding yeast to provide mass amount of research materials. They serve as an excellent model for studying meiosis.

We study based on molecular genetics to conduct experiments of genes that have influences on meiosis in budding yeast. By ways like genetics, biochemistry, molecular biology and cytology, we hope to gain further comprehensions about the controls of meiosis.

Tung, K.-S., L. L. Norbeck, S. L. Nolan, N. S. Atkinson, and A. K. Hopper. 1992. SRN1, a yeast gene involved in RNA processing is identical to HEX2/REG1, a negative regulator in glucose repression. Mol. Cell. Biol. 12 (6): 2673-2680.

Tung, K.-S. and A. K. Hopper. 1995. The glucose repression and RAS-cAMP signal transduction pathways of Saccharomyces cerevisiae each affect RNA processing and the synthesis of a reporter protein. Mol. Gen. Genet. 247: 48-54.

Saavedra, C., K.-S. Tung, D. C. Amberg, A. K. Hopper, and C. N. Cole. 1996. Regulation of mRNA export in response to stress in Saccharomyces cerevisiae. Genes & Dev. 10: 1608-1620.

Traglia, H. M., J. P. O'Connor, K.-S. Tung, S. Dallabrida, W.-C. Shen, and A. K. Hopper. 1996. Nucleus-associated pools of Rna1p, the Saccharomyces cerevisiae Ran/TC4 GTPase activating protein involved in nucleus/cytosol transit. Proc. Natl. Acad. Sci. USA 93: 7667-7672.

Tung, K.-S. and G. S. Roeder. 1998. Meiotic chromosome morphology and behavior in zip1 mutants of Saccharomyces cerevisiae. Genetics 149: 817-832.

Tung, K.-S., E. Hong, and G.S. Roeder. 2000. The pachytene checkpoint prevents accumulation and phosphorylation of the meiosis-specific transcription factor Ndt80. Proc. Natl. Acad. Sci. USA 97: 12187-12192.

Wang, Y., C.-Y. Chang, J.-F. Wu, and K.-S. Tung. 2011. Nuclear localization of the meiosis-specific transcription factor Ndt80 is regulated by the pachytene checkpoint. Mol. Biol. Cell. 22: 1878-1886. A Highlights from MBoC Selection. Selected and recommended by the Faculty of 1000.