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.
>>> Molecular and Developmental Cell Biology >>> Plant Molecular Biology >>> Molecular Cell Biology
>>> Membrance Cell Biology >>> Molecular Genetics >>> Molecular Neuroscience
>>> Chromosomal Functions >>> Protein Science and Cellular Biochemistry
■Molecular and Developmental Cell Biology
Associate Professor Kazuya Nomura
The nematode Caenorhabditis elegans is an ideal model organism for functional genomics. The human genome and the nematode genome have many glycome-related genes in common. In our laboratory, we select human glycome-related genes systematically and study the functions of genes by using the nematode. RNAi and deletion mutagenesis are systematically used for this purpose, aiming toward the complete functional analysis of glycome-related genes and associated gene networks. Special attention is paid to the roles of molecules present in the outer most layers of cell membranes that control cell surface molecules or mediating infection.
■Plant Molecular Biology
Professor Koh Iba
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.
■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
Associate 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.
Professor Takeshi Ishihara
Animals process various kinds of sensory information in their nervous systems to regulate their behavior. To elucidate those mechanisms at molecular and neural network levels, we study the behavioral regulation of C. elegans as a model system, by using molecular genetics, behavioral analyses, and imaging studies on the neural network. Among many kinds of information processing, we focus on the behavioral plasticity, sensory integration, olfaction, and behavioral regulation by internal environments. We also analyze the effects in C. elegans of medical drugs that target manic depression. These studies will provide fundamental insight into the function of central nervous systems in animals.
Associate Professor Makoto Koga
The most significant thing for organisms, and the primary function of their behavior, is to maintain their populations and produce offspring for the next generation. Efficient foraging, strategic utilization of food resources, and successful sexual reproduction are among the most important activities for organisms. The healthy functioning of the cerebral nervous system is necessary for all organisms to achieve these behaviors, from mammals with a complex nervous system to creatures with relatively simple nervous systems such as the a wooly aphid. Our research centers on molecular genetic analysis, using C. elegans as a model, to study the behavioral changes and control mechanisms relating to eating behavior.
Professor Isao Ito
eft-right (L-R) asymmetry is a fundamental feature of higher-order neural function. Conventional laterality research dealt with asymmetries in higher-order functions and macroscopic structures of the brain. However, the molecular basis of brain asymmetry remains unclear. We found functional and structural asymmetry of hippocampal circuitry caused by differential allocation of N-methyl-D-aspartate receptor (NMDAR) subunit GluRε2 (NR2B) in hippocampal synapses. The synaptic distribution of ε2 subunits and the NMDAR-mediated synaptic functions provide sensitive and quantitative indices for detecting abnormalities in the L-R asymmetry of the brain. Using these indices in combination with multidisciplinary research, we explore the molecular basis of brain asymmetry.
Professor Toshiki Tsurimoto
Precise DNA replication in eukaryotic cells is essential for the maintenance of genome integrity during cell proliferation. This step is also crucial for the coordination of various cellular signals with cell proliferation through regulation of DNA damage responses, reorganization of chromosomal structures and segregation of sister chromatids, and thus tightly involved in differentiation, cancer-development, and the aging of eukaryotic cells. Our major interest is in understanding the molecular dynamics of the replication fork complex in human cells, focusing on functions of its major components, clamp and loader complexes. We have taken molecular biological and biochemical approaches to study their molecular interaction networks and structure-function relevance.
■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.
Associate Professor Takumi Koshiba
Mitochondria are dynamic organelles that undergo cycles of homotypic fusion and fission events, which are believed to play an important role in controlling organelle numbers, subcellular distribution, morphology, and ATP production. In some cells, fusion of numerous mitochondria into a well-organized reticulum is thought to enable transmission of the mitochondrial membrane potential, thereby facilitating ATP generation to active regions of the cells. However, the reality of the mitochondrial dynamics and their functional significance still has plenty of room for further understanding. Our lab is trying to decipher the relationship between mitochondrial dynamics and its physiological relevancy, especially for the human metabolism and immune response system. To address this issue, we use a wide range of approaches, including cell biology, biochemistry, and biophysics.