Laboratory/Faculty

Laboratory of Developmental Biology
Group of Development and Growth Regulation

Associate ProfessorYasushi Yoshioka
Organelle functions in plant development
Associate ProfessorShin Takagi
Semaphorin/Plexin system
LecturerShin Sugiyama
The Secret Behind Drosophila Giant Mitochondria
LecturerAkira Kanamori
What small fish teach us about gonadal sex differentiation
Assistant ProfessorYoshimasa Yagi
Regulation mechanism of innate immunity of Drosophila melanogaster
Laboratory HP
Japanese
Lab members

 Our research group consists of five faculty members, each of whom has his own research projects described below. Although the organisms and approaches we use in our research vary, we all share strong interest in molecular and cellular mechanisms by which development and growth are regulated.

Organelle functions in plant development

Plastids and mitochondria are supposed to play important roles in plant development and growth mainly through various organic materials and retrograde signals. However, how these organelles regulate plant development remains unclear. Our main research object is to elucidate roles of organelles in plant development. We use model plants, Arabidopsis thaliana and Physcomitrella patens, for our research.

Semaphorin signaling

Semaphorins compose a major group of morphogenetic signaling molecules conserved in animals. Using a simple model animal C. elegans, we are trying to understand cellular and molecular mechanisms underlying the Semaphorin-mediated morphogenesis. Our studies have revealed that semaphorin signaling is tightly linked to mTOR signaling pathway. An unexpected finding is that the cellular morphogenesis involves highly divergent cellular events such as mRNA translation and membrane dynamics. We have also developed a novel method, IR-LEGO, exploiting heat-shock response for manipulating gene expression at the single-cell level in C. elegans. IR-LEGO will be a powerful tool for analyzing development and the nervous system.

What small fish teach us about gonadal sex differentiation

 I am studying sex differentiation of germ cells, namely branching point toward sperms or eggs.  My main interests are germ cell differentiation and interaction between germ and somatic cells during this process.  I chose teleost fish for the study since their germ cells can differentiate into mature sperms or eggs irrespective of genetic sexes unlike mammals and they exhibit extreme diversity in sex determination/differentiation.  Medaka is our favorite.  Its sex-determining gene has been identified and both genetic and reverse-genetic tools are readily available.  I have been conducting diverse lines of research in medaka such as identification of cis-regulatory elements in oocyte-specific genes by generating transgenic medaka and search for sex differentiation mutants by GFP medaka with oocyte-specific promoters.  I also use a hermaphrodite fish, Kryptolebias marmoratus, the only known self-fertilizing vertebrate. I analyze development of their ovotestis where small testicular tissue is differentiated in the dorsal side of the ovaries. The process is compared with that of K. caudomarginatus, closely related gonochoristic species.

The Secret Behind Drosophila Giant Mitochondria

The morphology of mitochondria change dramatically during spermatogenesis in Drosophila. First, the mitochondria proliferate in spermatogonia, then they fuse and increase in size in spermatocytes, and finally change shape to become over 1200 microns in length in sperm. This “morphogenesis” of mitochondria is probably possible due to the evolutionary triplication of the CTD phosphatase genes tim50 and dullard. Testes specific expression and specialization of the additional copies of these genes is anticipated to be what drives the above differentiation of sperm mitochondria. By revealing the details of the mechanisms that allow mitochondria to change in such a manner, it is hoped that interest in the developmental functions of this little organelle will be renewed.

Regulation mechanism of innate immunity of Drosophila melanogaster

The IMD pathway is one of the signaling pathways which regulate innate immunity of Drosophila. Using molecular genetic technique, I am analyzing the transcriptional regulation of the target genes of the IMD pathway.

 

References

  1. Mizoguchi, A., et al. (2013) Front. Physiol. 4, 217
  2. Mizoguchi, A., et al. (2013) PLOS ONE 8, e60824.

  3. Okamoto, N., et al. (2011) Gen. Comp. Endocrinol. 173, 171-182.

  4. Yamanaka, N., et al. (2010)Proc. Natl. Acad. Sci. USA 107: 2060-2065.

  5. Okamoto, N., et al. (2009) Dev. Cell 17, 885-891.

  6. Okamoto, N., et al. (2009) FEBS J. 276, 1221-1232.

  7. Iwata, E., et al. (2012) Plant Signal. Behav. 7, 1079-1081.

  8. Sugita, C., et al.(2012) Plant Cell Physiol. 53,1124-1133.

  9. Iwata, E., et al. (2011) The Plant Cell 23, 4382-4393.

  10. Fujiwara, M.T., et al. (2010) Protoplasma 242, 19-33.

  11. Chen, Y., et al. (2009) Plant Cell Physiol. 50, 956-969.

  12. Kanamori, A., et al. (2013) Emviron. Sci.Technol. 47, 6640.
  13. Kinoshita, M. et al. (2009) Mol. Reprod. Dev. 76, 202-207.

  14. Kanamori, A., et al. (2008) Gene 423, 180-187.

  15. Kanamori, A., et al. (2006) Genesis 44, 495-503.

  16. Uchino, et al. (2012). Dev. Biol. 373, 216-227.

  17. Liu, Z., et al. (2011). Develop. Growth Differ. 53, 822–841.

  18. Furukawa, K., et al. (2009). Exp. Cell Res. 315, 1181–1189.

  19. Sugiyama, S., et al. (2007). Genetics 176, 927–936.

  20. Ryan, H., et al.(2014) Immunity 40, 51.
  21. Yagi, et al. (2013) Genes to Cells 18, 934.
  22. Yagi, Y., et al. (2010) Dev. Growth Differ. 52, 771-783.

  23. Yagi Y. and Ip Y.T. (2005) EMBO Rep. 6, 1088-1094.


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