Ikawa Lab/Genome Information Research Center  Department of Experimental Genome Research

In the past, animals harboring natural mutations have been used to elucidate the mechanisms underlying various diseases.
In the “post-genome project era,” genetically modified animals play a key role in basic molecular biological investigations and act as models of human disease. Our laboratory studies the mechanisms underlying mammalian reproductive systems through genetic manipulation of animal models.

Alalysis of molecular mechanisms involved in mammalian reproduction

Our laboratory focuses to mechanistically study the mammalian reproduction system in vivo using gene-manipulated animals. We were the first laboratory in the world to produce genetically modified mice that express a green fluorescent protein (GFP) throughout the body (Fig. 1).

These green fluorescent mice are useful for many types of research projects. Indeed, we used these animals to label sperm with a fluorescent protein and visualized the fertilization process (Exp Anim. 2010; JCS. 2010, 2012; PNAS. 2012, 2013) (Fig. 2)


We introduced the cutting edge CRISPR/Cas9 system and have been improving the technology (SciRep. 2013, 2016; Science 2018). By utilizing the system, we have been working on the molecular mechanisms of gametogenesis and fertilization (PNAS.2016, 2018, 2019; Nat Commun 2016). Among these, we found that sperm calcineurin (PPP3CC/PPP3R2) is essential for sperm motility and male fertility (Science 2015). Inhibiting sperm calcineurin may lead to the development of a reversible male contraceptive. More recently, besides IZUM0 1 (Nature 2005), we found novel sperm proteins essential for the sperm-oocyte fusion process (two PNAS papers in revision). Our laboratory will continue elucidating the mammalian fertilization mechanism.


Development of new technologies for producing genetically modified animals

Another tool improved by work in our laboratory is lentiviral (LV) vector-mediated genetic manipulation in vivo. We developed the technique of placenta-specific gene manipulation by transducing blastocyst stage embryos with LV vectors (Nat Biotechnol. 2007; PNAS. 2011). Using this technique, we are trying to elucidate the mechanism underlying implantation and placentation.


Our laboratory and the Animal Resource Center for Infectious Diseases support services such as the generation of genetically modified animals, in vitro fertilization, and cryopreservation of mouse strains.


For more information about our research and services, please visit our homepage (https://egr.biken.osaka-u.ac.jp/).



  • Fig. 1. GFP-expressing mice. Our “Green mice” have been used for more than hundreds of researchers and are good models for studying human disease (FEBS Lett 1997;407:313-319).
    Fig. 2. RBGS sperm. Transgenic spermatozoa carrying GFP and dDsRed2 in their acrosome and mitochondria. These gametes are useful to visualize the fertilization process (Exp Anim 2010;59:105-107).

  • Fig. 3. Calcineurin deficient sperm. Serm calcineurin is required for sperm motility for successful fertilization (Science 2015;350:442-445).

  • Fig. 4. Lentirival vector-mediated transgenesis in mice. Lentiviral vectors are not able to transduce eggs with zona pellucida (ZP) (left). Without ZP, transductions of fertilized egg and blastocyst result in the whole transgenic (middle) and placenta-specific transgenic (right), respectively (Nat Biotechnol 2007;25:233-237).


  • Prof.: Masahito Ikawa
  • Assoc. Prof.: Haruhiko Miyata
  • Assoc. Prof.: Norikazu Yabuta(concur.)
  • Asst. Prof.: Keisuke Shimada(concur.)
  • Asst. Prof.: Daiji Kiyozumi
  • Asst. Prof.: Chihiro Emori
  • SA Asst. Prof.: Tsutomu Endo (concur.)
  • SA Asst. Prof.: Julio Castaneda
  • SA Asst. Prof.: Lu Yonggang
  • JSPS Research Fellow: Nobuyuki Sakurai
  • JSPS Research Fellow: Yamauchi (Ishikawa) Yu
  • Guest Professor: Martin M. Matzuk
  • Guest Associate Professor: Yoshitaka Fujihara
  • Guest Researcher: Masaru Okabe



  • (1) Nexin-Dynein regulatory complex component DRC7 but not FBXL13 is required for sperm flagellum formation and male fertility in mice. Morohoshi A., et al. PLOS Genet (2020) 16(1):el008585.
    (2) Identification of multiple male reproductive tract-specific proteins that regulate sperm migration through the oviduct in mice Fujihara Y., et al. PNAS (2019) 115 (37):18498-506.
    (3) TCTE1 is a conserved component of the dynein regulatory complex and is required for motility and metabolism in mouse spermatozoa. Castaneda J.M., et al., PNAS (2018) 114 (27):E5370-E5378
    (4) Structural and functional insights into IZUMO1 recognition by JUNO in mammalian fertilization. Kato K., et al., Nat Commun (2016) 7:12198.
    (5) Genome engineering uncovers 54 evolutionarily conserved and testis-enriched genes that are not required for male fertility in mice. Miyata H., et al., PNAS (2016) 113(28):7704-10.
    (6) Sperm calcineurin inhibition prevents mouse fertility with implications for male contraceptive. Miyata H., et al., Science (2015) 350(6259):442-5.