Germ cells are the sole and fundamental cells to leave offspring. Although germ cells in an animal body would be strictly regulated to avoid aberrant proliferation, cell death, and differentiation due to its biological significance, the regulatory mechanisms of germ cells have been largely unknown. To address the issues, we study the developmental mechanisms of germ cells in vertebrate embryos, focusing on the cellular and molecular interactions between germ cells and environmental somatic cells, in the contexts of germ cell maintenance and migration. We progress these researches by maximizing the advantages of avian system including in vivo high quality imaging, cell/tissue transplantation, germ cell culture, and transgenic chickens and quails. In addition to basic developmental researches, we are also interested in various applications of avian reproductive engineering.
Division of Molecular Life Sciences
The eukaryotic cell is a core structural unit that constitutes the bodies of higher organisms, and operates various activities of life with highly sophisticated membrane structures. The Division of Molecular Life Sciences conducts research into the integrated biology of animals and plants from basic structures of genes to high-order functions of bodies by focusing on the following aspects; mechanisms of chromosomal DNA replication for maintaining genome structures, molecular dynamics of high-ordered structures from protein complexes to organelles managing cellular functions, for example, signaling mechanisms of cell-cell communication for cell proliferation, cell formations and metabolism regulation mechanistic features of functions in individual bodies including development and differentiation, and formation of neural networks and immune systems. We also provide basic lectures to students concerning other divisions aiming to understand molecular biology of life from molecular, cellular and individual aspects. The lectures include basic structures and functions of the cell, developmental mechanisms of individual bodies from fertilization to highly organized cell societies, and the coordination of nerve systems to manage high-ordered biological activities.
■Animal Developmental Biology and Reproductive Engineering
Professor Daisuke Saito
■Functional Cell Biology
Associate Professor Takayuki Teramoto
Our research focuses on how the brain processes sensory information. To approach this, we use a small round worm, C. elegans and 4D imaging technique. By imaging of the whole- brain activity at neuronal level, we aim to light up the neuronal mechanisms for information processing by the brain.
Lecturer Nobushige Nakajyo
We are interested in cell-cycle control in early development and cell differentiation. Accordingly, we are investigating the cell cycle, signal transduction, cell growth, and cell differentiation in early development, using the amphibian Xenopus system.
Lecturer Yoshifumi Yamawaki
The praying mantis adjusts the trajectory of foreleg movements
during predatory strike depending on the prey position. The
process transforming sensory information into motor commands
is called “sensory-motor transformation”, but little is known about
the mechanism underlying it. We investigate the structure and
function of nervous system in the mantis to clarify the neural basis
of sensory-motor transformation.
■Plant Molecular Biology
Professor Koh Iba
At the Laboratory of Plant Molecular Biology, the functions of plant cells related to environmental adaptability are studied using genetic engineering approaches. Our efforts focus on the model plants Arabidopsis and rice. The objective is to characterize the key genes involved in the adaptation of plants to stress factors such as temperature, CO2, and pathogen invasion. By analyzing the functions of these genes in detail, we gain an understanding of the molecular mechanisms by which plants adapt to their environments.
Associate Professor Juntaro Negi
Guard cell chloroplasts have been proposed to play an
important role in the osmoregulatory mechanisms mediating
stomatal and remains to be confirmed. To elucidate the precise
role of guard cell chloroplast, we isolated an Arabidopsis mutant
that had non-chlorophyllous stomata. By analyzing this mutant in
detail, we are aiming to establish the molecular mechanisms by
which guard cell chloroplasts perceive environmental signals.
■Molecular Cell Biology
Professor Shigehiko Tamura
Peroxisomes are present in a wide variety of eukaryotic cells, from yeast to humans, and function in various metabolic pathways, including the β-oxidation of very long chain fatty acids and the synthesis of ether-lipids. The functional consequence of human peroxisomes is highlighted by fatal genetic peroxisome biogenesis disorders (PBD), including Zellweger syndrome, all of which are linked to a failure of peroxisome assembly. In our studies we aim to elucidate the molecular mechanism of peroxisome biogenesis and protein trafficking in eukaryotes
■Membrance Cell Biology
Professor Junichi Ikenouchi
Epithelial cells are constitutively polarized to play fundamental functions such as vectorial transport. There are two membrane domains of epithelial cells, the apical membrane and separated by cell adhesion apparatus. To understand the molecular mechanisms of epithelial polarity and cell adhesion, our lab has identified important proteins involved in these processes. In addition to the researches focused on proteins, we are now trying to clarify the roles of membrane lipids in epithelial cells. The aim of our study from the viewpoint of basic science is to clarify the roles of individual lipid species by using epithelial polarity and cell adhesion as experimental systems. The research purpose for clinical science is to find novel therapeutic targets in diseases correlated with epithelial-polarity disorders and epithelial-mesenchymal transition, such as cancer, polycystic kidney disease and pulmonary fibrosis.
Lecturer Kenji Matsuzawa
Collective cell movement, in which a group of cells remain
adhered to each other and move as a unit, is a fundamental
phenomenon during development and a hallmark of invasive
cancers. However, much of the molecular mechanisms that
underlie collective cell behavior are unknown. I approach this
question from the perspective of the many forms of dynamic cell
communication tools available to cells, with a special focus on the
cell adhesion machinery.
Professor Takeshi Ishihara
Associate Professor Makoto Koga
Associate Professor Manabi Fujiwara
Associate Professor Tatsuro Takahashi
DNA and chromatin proteins. Duplication, segregation, and
maintenance of chromosomes rely on the interplay between
various different reactions. An extract of Frog eggs is an only in
vitro system that simultaneously recapitulates various reactions
acting on chromosomes, and therefore it is a good model for
chromosome research. We use this system to study how mismatch
repair, a reaction that maintains the fidelity of DNA replication,
cooperates with DNA replication and chromatin assembly. We
also study how chromosome cohesion, a reaction that connects
duplication and segregation of chromosomes, is established during
the process of DNA replication.
Associate Professor Eiji Nitasaka
The Japanese morning glory (Ipomoea nil ) is known not only
as a horticultural plant but also a model organism in various fields
of scientific study such as genetics, physiology, natural product
chemistry, and evolutionary biology. Many flower/leaf color and
morphological mutants were isolated in the late Edo era, and
are still maintained in our laboratory as a part of National Bio-
Resource Project (NBRP) of the AMED. Recent molecular studies
revealed that the most mutants of I. nil were induced by CACTArelated
transposable elements, Tpn1 family carrying common
terminal repeated sequences. We also have a large mutant
collection of I. purpurea which is a sibling species of I. nil, and they
are induced by transposons belonging to hAT, MULE and Helitron
superfamilies. Therefore, Ipomoea species are superior materials
to study the biology of transposable elements. Our research
mainly focuses on the structures and transposition mechanisms
of transposons and developmental mechanisms of plants using
our mutant collection. Highly deformed mutants were shown to be
defective in axis formation genes such as FIL(YABBY ) and KANorthologs
controlling abaxial-adaxial cell fates.
Lecturer Kensuke Kusumi
Our research focuses on the molecular mechanism underlying plant
response and adaptation to its environment. Because higher plants
cannot move from their environment, they evolved the ability to adapt
to changes in climate and environment. Research programs in our
lab have evolved from the study of phenotypic response of rice (Oryza
sativa) to changing environments to studies of 1) CO2 response of
growth and production, 2) regulation of nutrient uptake by modulating
organ development, and 3) growth homeostasis under high/low
temperatures. We aim at a deeper understanding of how plants adapt
in a changing environment and allocate resources among organs to
optimize whole plant growth.
■Protein Science and Cellular Biochemistry
Professor Shun-ichiro Kawabata
Our laboratory specializes in protein science and cellular biochemistry, which include biochemical and biophysical characterization of native or recombinant proteins involved in innate immunity. We have been conducting studies on molecular mechanisms of invertebrate innate immunity using the horseshoe crab Tachypleus tridentatus and Drosophila melanogaster. Interactions between protein and other biomolecules including lipids and carbohydrates are measured by surface plasmon resonance and quartz crystal microbalance analyses. Physiological functions of the identified proteins are also characterized in vivo by RNAi in the Drosophila system. Three dimensional structures of proteins and peptides are determined in collaboration with other laboratories through X-ray crystal and NMR analysis.