Epigenetic mechanisms, such as DNA methylation, histone modifications and heterochromatin formation, regulate and maintain gene activity of cells without changing the DNA sequence. These mechanisms are important for developmental gene regulation and transposon silencing. They are also involved in mammalian-specific epigenetic phenomena, such as genomic imprinting and X chromosome inactivation.

The following research projects are ongoing in our lab:

• Mechanisms of parental imprinting in germ cells.
• Mechanisms of transposon silencing by small RNA.
• Structure, regulation and evolution of imprinted genome domains.
• Role of non-coding RNA in X chromosome inactivation.
• Role of epigenetics in human disorders.
• Role of epigenetics in phenotypic variation and evolution.
• Development of new techniques for epigenetics studies.

Hoki, Y., Kimura, N., Kanbayashi, M., Amakawa, Y., Ohhata, T., Sasaki, H. and Sado, T. (2009). A proximal conserved repeat in the Xist gene is essential as a genomic element for X-inactivation in mouse Development. 136, 139-146.

Hirasawa, R., Chiba, H., Kaneda, M., Tajima, S., Li, E., Jaenisch, R. and Sasaki, H. (2008). Maternal and zygotic Dnmt1 are necessary and sufficient for the maintenance of DNA methylation imprints during preimplantation development. Genes Dev. 22, 1607-1616.

Watanabe, T., Totoki, Y., Toyoda, A., Kaneda, M., Kuramochi-Miyagawa, S., Obata, Y., Chiba, H., Kohara, Y., Kono, T., Nakano, T., Surani, M.A., Sakaki, Y. and Sasaki, H. (2008). Endogenous siRNAs from naturally formed dsRNAs regulate transcripts in mouse oocytes. Nature. 453, 539-543.

Sasaki, H. and Matsui, Y. (2008). Epigenetic events in mammalian germ-cell development: reprogramming and beyond. Nat. Rev. Genet. 9, 129-140

Ichiyanagi, K., Nakajima, R., Kajikawa, M. and Okada, N. (2007). Novel retrotransposon analysis revealed multiple mobility pathways dictated by hosts. Genome Res. 17, 33-41

Sado,T., Hoki,Y., and Sasaki,H.(2005). Tsix silences Xist through modification of chromatin structure. Dev. Cell 9, 159-165.

Kaneda, M., Okano, M., Hata, K. et al. (2004). Essential role for de novo DNA methyltransferase Dnmt3a in paternal and maternal imprinting. Nature 429, 900-903.