Bioscience and Biotechnology Center

Animal Organ Function Group
Faculty and Research Theme
Yuko Wakamatsu Professor

Yuko Wakamatsu (Professor)

Studies of polycystic kidney disease using a medaka mutant

Kinya Yoda (Associate Professor)

Structure and function of mammalian centromeres

Hisashi Hashimoto (Assistant Professor)

Development of nuclear transplantation and gene targeting techniques in medaka
Medaka, a small freshwater fish, is a good vertebrate model organism. In our laboratory, we have performed studies using medaka for over half a century. During this period, many medaka resources have been developed; most of these are natural mutants with various abnormal phenotypes in pigmentation, morphology, and behavior. We use these resources for studies of hereditary diseases and nuclear transplantation, and for development of new strains such as the transparent medaka. We also distribute these medaka resources to the research community. The structure and function of mammalian centromeres are also studied in our laboratory.

1) The transparent medaka
Medaka and zebrafish are good models for developmental biology because the embryonic body is transparent therefore easy to observe. However, after hatching, the fish become pigmented and lose transparency. By crossing mutant strains with pigment deficiencies, we have established a new strain, the transparent medaka, whose adult body wall is transparent, and whose internal organs can be observed. This strain is used for studies in medical and biological sciences, and ecotoxicology.

2) Studies of polycystic kidney disease using a medaka mutant
Because of similarities in organ structures and genes, fish models can be used for studies of certain human diseases. One of our natural medaka mutants, pc, shows severe swelling and many large cysts in the kidney at the adult stage. This phenotype is similar to the hallmarks of human polycystic kidney disease, a common hereditary kidney disease. We are studying the developmental processes of this disease and analyzing the structure and function of the pc gene, which has been successfully cloned in our laboratory.

3) Nuclear transplantation for fish cloning using medaka
Animal cloning has been successfully achieved in mammals. This technique is important for studies of gene function and for the production of clones. Using medaka, we are trying to establish this technique in fish.

4) Structure and function of mammalian centromeres
This figure shows a HeLa cell in mitotic phase. Green shows fibrous materials called microtubules, which attach to centromeres (red), pull apart and segregate daughter chromosomes to daughter cells. This dynamic process is highly regulated by various signals.
Using cultured human cells, our group studies how chromosomes are equally distributed to daughter cells after DNA duplication. A DNA fiber greater than 2 meters long is orderly folded into a chromatin structure (blue color in photo). Our interest is focused on the centromere/kinetochore (red dotted particles in photo), which plays an important role in chromosome segregation and checkpoint control during metaphase.
Prof. Wakamatsu and members of her group
References
Medaka
  1. Mochizuki E. et al. (2005) Kidney Intl., 68: 23-34.
  2. Kelsh R. et al. (2004) Mech. Dev., 121: 841-859.
  3. Hashimoto H. et al. (2004) Development, 131: 1741-1753.
  4. Ju B. et al. (2003) Dev. Growth Dif., 45: 167-174.
  5. Wakamatsu Y. et al. (2001) PNAS, 98: 1071-1076.
  6. Wakamatsu Y. et al. (2001) PNAS, 98: 10046-10050.
Centromere
  1. Yoda K. et al. (2004) Lancet, 364: 1022-1024.
  2. Yoda K. et al. (2004) Methods Enzymol., 375: 270-277.
  3. Obuse C. et al. (2004) Genes to Cells, 9: 105-120.
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Japanese

Molecular Neurobiology Group

Biological Rhythm Group (Chronobiology)

Evolutionary Genetics Group

Plant Reproductive Systems

Pattern Formation Principles Group

Plant Developmental Biology Group

Animal Development Group

Brain Function and Structure Group

Gene Regulation Group

Molecular and Cell Biology Group

Supra-molecular Structure Group

Biomembrane Functions Group

Developmental Morphogenesis Group

Signal Transduction Group

Plant Growth Physiology Group

Cell Biology Group

Developmental Biochemistry Group

Laboratory of Gene Analysis

Laboratory of Functional Genomics and Clock Bio-nanomachines

Animal Organ Function Group

Biochemistry Group

Photobioenergetics Group

Nervous Development Systems Unit

Intracellular Dynamics Unit