New Insights into the Development of Epithelial Cells MDC Researchers Discover More Diversity than Expected
Scientists worldwide use zebrafish to study the development
of vertebrates, the group to which humans also belong. Zebrafish are only a few
centimeters long and their embryos are transparent, which is why researchers
can observe every change under the microscope. In the early development of
zebrafish, the heart is like a tube surrounded by a pump of epithelial cells.
The upper and lower sides of an epithelial cell are clearly
different. The upper side, which forms a boundary between organs and either
tissue fluid, hollow spaces, or the environment, has a different function than
the lower side facing the connective tissue. Both poles of an epithelial cell are
vital for the functioning of the heart and other organs.
Different proteins
steer cell polarity
Until now, the scientists had assumed that the development
of the cell poles was steered by a protein complex which scientists call
Crumbs/Nagie oko complex. “What is surprising is that, depending on the tissue,
the protein complex has a different composition while being fully functional,”
Dr. Abdelilah-Seyfried explained. Thus, some proteins in the heart are not
needed, but for the development of epithelial cells of the retina they are
fundamental. “The program as understood previously may apply for individual
cells in the laboratory,” Dr. Abdelilah-Seyfried said, “but in a complex
organism like the zebrafish, there are many deviations.” In the opinion of the researchers,
these deviations indicate that the epithelial cells have adapted to their tasks
in the respective tissue. Until now, these processes have not been fully
elucidated. Next, the MDC researchers want to find out whether still more
proteins are involved in epithelial cell polarization.
*Divergent polarization mechanisms during
vertebrate epithelial development mediated by the Crumbs complex protein Nagie
oko
Nana Bit-Avragim1,2,*, Nicole
Hellwig1,*, Franziska Rudolph1, Chantilly Munson3,
Didier Y.S. Stainier3 and Salim Abdelilah-Seyfried1,‡
1Max Delbrück Center (MDC) for Molecular Medicine,
Berlin, Germany
2Department of Cardiology, The Charité University
Medical School of Berlin, Campus Buch, Campus Virchow Clinics, Berlin, Germany
3Department of Biochemistry and Biophysics and
Programs in Developmental Biology, Genetics, and Human Genetics, Cardiovascular
Research Institute, University of California, San Francisco, CA 94143 – 2711, USA
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