Laboratory of Cell Biology
Graduate School of Science
Professor

Kenji MATSUNO

Associate Professor Daiki UMETSU

kmatsuno
Daiki.umetsu.sci

URL: https://www.bio.sci.osaka-u.ac.jp/bio̲web/lab̲page/matsuno/
The body of a complex multicellularorganism is formed through systematic
assembly of many different cells.
Therefore, the "life" of an organism
depends on the integration of diverse
functions exerted by these cells. For
example, cells determine their own
destinies by exchanging information
among themselves. However, it is still
elusive how cells perform their amazing
functions.
Our laboratory is interested in how
cells function in the development ofanimal tissues and organs according togenetic programs. We are challenging
this question using Drosophila, in whichwhole varieties of genetic tools andcomprehensive genomic andchromosomal information are available.
Chirality of cells makes theanimal body left-right asymmetric
Even in animals that are left-rightsymmetrical in appearance, their internalorgans are often left-right asymmetrical. A
good example is the left-right asymmetryof human internal organs. The mechanisms
underlying the formation of such left-rightasymmetries are evolutionarily diverse andlargely unknown in invertebrates.
Drosophila is an ideal laboratory animal
for studying the formation of left-rightasymmetry, because of its geneticallydetermined and clear left-right asymmetry.
Our laboratory uses the Drosophilamelanogaster to study the mechanisms bywhich left-right asymmetry is formed. We
have revealed for the first time that cells
exhibit chirality (the property that themirror image does not overlap with its
original), which is the basis to form theleft-right asymmetry of the body. We
searched for mutants that reverse the leftright asymmetry of the gastrointestinal
tract, and found that various genes
required for the left-right asymmetricdevelopment of this organ.

In addition, we have succeeded inidentifying genes that invert (mirror)
cellular chirality and the left-rightasymmetric organs. We are currently
investigating the mechanism of left-rightasymmetric tissue deformation caused bycellular chirality by computer simulationof tissues composed of three-dimensionalmodel cells that exhibit cellular chirality.
In addition, we are elucidating themolecular mechanism how cellularchirality is formed in Drosophila
macrophages.
Intercellular signaling via cell-to-cell
contact-Notch signaling pathway
Cell-to-cell communication is essential
for development and homeostasis in
multicellular animals. The exchange of
information between cells is the basis forthe orderly behavior of cells. In recentyears, great progress has been made in
our understanding of the mechanisms ofcell-to-cell communication. However,many mysteries remain unsolved.
Receptor proteins on the surface of theplasma membrane are responsible for the
reception of information between cells.
These are proteins that "receive"
information, called as receptors.
Notch is a receptor protein that
presented at the plasma membrane.
Proteins that sends information from theneighboring cells to Notch, designated asligands, are also transmembrane proteins.
Therefore, Notch receives information
only when direct cell-cell contact exists
between signal sending and receivingcells. This mechanism allows intercellularcommunication to occur through cell-cellcontact. This signaling pathway is called
Notch signaling pathway, which functions
in a variety of cell-fate decisions andmorphogenesis. Therefore, abnormalities
in Notch signaling are known to cause ofvarious human diseases, including
cancers. We are studying the mechanismof Notch signaling and its regulation inDrosophila.

Figure 1.
The digestive tract of a Drosophila embryo (parts in green, purple,and blue) is left-right asymmetric. The left panel shows a ventral
view, and the right panel shows a dorsal view/

Figure 2.
The nervous system of a wild-type Drosophila embryo (purple) is aladder-like nervous system; in the embryo carrying a mutant of thegene encoding the Notch receptor, cell-to-cell communication is
dysfunctional and cell differentiation is disrupted. As a result, allcells that are normally epidermal are converted to neural cells.

There is still a lot of uncharted
territories in biology. In otherwords, there is still a lot of fun
waiting for us.

Department of Biological Sciences
Graduate School of Science, Osaka University
1-1, Machikaneyama-cho, Toyonaka, Osaka
560-0043, Japan
TEL: +81-6-6850-5804
FAX : +81-6-6850-5805
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