The University of Tokyo · Medicine
Professor Tomoko Nakanishi's research lab specializes in reproductive biology and genetic engineering, focusing on sperm cell function, acrosome reaction dynamics, and male fertility mechanisms using transgenic mouse models. The lab employs advanced imaging techniques, such as live fluorescent microscopy, to visualize subcellular events in sperm, particularly the acrosome reaction, and investigates the roles of specific proteins like calmegin in sperm migration and fertilization. Additionally, the lab contributes to human health research by studying genetic disorders such as alpha-1 antitrypsin deficiency through population-scale genomics, including polygenic risk scores and phenome-wide association studies. The lab also extends its expertise to environmental health, examining the long-term impacts of radioactive contamination from the Fukushima nuclear accident on ecosystems and agricultural systems.
Figures are computed from collected data and may differ slightly.
We produced transgenic mouse lines that accumulate mutated green fluorescent protein (EGFP) in sperm acrosome, a membrane limited organelle overlying the nucleus. The sperm showed normal fertilizing ability and the integrity of their acrosome was easily examined in a non-invasive manner by tracing the GFP in individual 'live' sperm with fluorescent microscopy. The time required for the dispersal of acrosomal contents was demonstrated to be approximately 3 s after the onset of acrosome reaction.
Loss of calmegin, a testis-specific putative chaperone protein of the endoplasmic reticulum, leads to male sterility because the sperm show defects in migration into the oviduct and do not bind to the zona pellucida. To clarify the mechanism of defective migration, XY <--> XY chimeras were produced by aggregating wild-type embryos with embryos of transgenic mice lacking functional calmegin genes and expressing enhanced green fluorescent protein (EGFP) in their acrosomes. Chimeric ejaculates cont
Alpha-1 antitrypsin deficiency (AATD), mainly due to the PI*ZZ genotype in <i>SERPINA1</i>, is one of the most common inherited diseases. Since it is associated with a high disease burden and partially prevented by smoking cessation, identification of PI*ZZ individuals through genotyping could improve health outcomes.We examined the frequency of the PI*ZZ genotype in individuals with and without diagnosed AATD from UK Biobank, and assessed the associations of the genotypes with clinical outcomes
More than 4 years has passed since the accident at the Fukushima Nuclear Power Plant. Immediately after the accident, 40 to 50 academic staff of the Graduate School of Agricultural and Life Sciences at the University of Tokyo created an independent team to monitor the behavior of the radioactive materials in the field and their effects on agricultural farm lands, forests, rivers, animals, etc. When the radioactive nuclides from the nuclear power plant fell, they were instantly adsorbed at the si
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