The main purposes of our laboratory are to understand sex differentiation and reversal, and regulation of germline stem cells in vertebrates. Taking advantage of medaka as a model organism, we employ two complementary strategies to address the above issues; visualization of cells in living medaka (Fig.1), which allows us to identify and isolate cell lineages, and understand the cellular interactions of the cells of interest; and positional cloning of mutant medaka exhibiting gonadal dysgenesis and sex reversals (Fig.2), leading to identification and functional analysis of the target genes.
Recently, for the first time in vertebrates, we have identified germline stem cells in the ovary and its niche structure. We have also found novel functions of germ cells; Germ cells are deeply committed to proper sex differentiation and maintenance. Now we are identifying the factors involved in the regulation of sex by germ cells and are analyzing the relation between regulation of germline stem cells and regulation of sex differentiation. We are now exploring the new field of "sex of germline stem cells".
Fig.1 olvas-GFP trangenic medaka. Germ cells can be monitored by fluorescence.
Fig.2 totoro mutant. This mutant is obtained by chemical mutagenesisand exhibits gonadal hypertrophy and sex reversal. The large swelled abdomen is occupied with gonads.
This laboratory is currently recruiting graduate students.
Capel, B. and Tanaka, M. Forward to the Special Issue on Sex Determination Dev. Dyn. (2013) 242, 303-306.
Forward on the special issue of ‘sex determination’, edited by Capel and Tanaka.
Nakamura, S., Watanabe, I., Nishimura, T., Picard, J-Y., Toyoda, A., Taniguchi, Y., di Clemente, N. and Tanaka, M. Hyperproliferation of mitotically active germ cells dues todefective anti-Müllerian hormone signaling mediates sex reversal in medaka.
Development (2012) 139, 2283-2287.
Nakamura, S., Watanabe, I., Nishimura, T., Toyoda, A., Taniguchi, Y. and Tanaka, M. Analysis of medaka sox9 orthologue reveals a concerved role in germ cell maintenance. PLoS ONE (2012) 7(1), e29982. Faculty of 1000 “RECOMMENDED”
Nakamura, S., Kobayashi, K., Nishimura, T., Higashijima, S. and Tanaka, M. (2010). Identification of germline stem cells in the ovary of teleost medaka. Science 328, 1561- 1563.
Aoki, Y., Nakamaura, S., Ishikawa, Y. and Tanaka, M. (2009). Expresssion and systenic analysis of four nanos genes in medaka. Zool. Sci. 26, 112-118.
Kurokawa, H., Saito, D., Nakamura, S., Katoh-Fukui, Y., Ohta, K., Aoki, Y., Baba, T., Morohashi, K., and Tanaka, M. (2007). Germ cells are essential for sexual dimorphism in the medaka gonad. Proc. Acad. Natl. Sci. USA 104, 16958-16963. (Direct Submission to PNAS Office)
Morinaga, C., Saito, D., Nakamura, S., Sasaki, T., Asakawa, S., Shimizu, N., Mitani, H., Furutani-Seiki, M., Tanaka, M. (Corresponding Author), and Kondoh, H. (2007). The hotei mutation of medaka in the anti- Mullerian hormone receptor causes the dysregulation of germ cell and sexual development. Proc. Acad. Natl. Sci. USA 104, 9691-9696. (Direct Submission to PNAS Office)
Tanaka, M., Kinoshita, M., Kobayashi, D., and Nagahama, Y. (2001). Establishment of medaka (Oryzias latipes) transgenic lines with the expression of green fluorescent protein fluorescence exclusively in germ cells: A useful model to monitor germ cells in a live vertebrate. Proc. Natl. Acad. Sci. USA. 98, 2544 - 2549. (Direct Submission to PNAS Office)
Associate Professor TANAKA, Minoru TEL: +81 564 59 5851 E-mail: email@example.com