Decyphering The Genetic Program Of The Eye В¬ Thanks To Balzan Prize Money

The number of genes activated during eye development
increases by up to 400 percent. That was one of the surprising results of a
research project on the fruit fly carried out at the University of Basel
(Switzerland). The project was financed to a large extent by the 2002 Balzan
Prize for Developmental Biology, which was awarded to Prof. Walter Gehring.
A total of over 150,000 measurements of gene activity during eye development
were analysed and have been made available in a publicly accessible
database.



Insects have complex compound eyes and vertebrates have inverse lens eyes.
However, although these types of eye are very different in terms of their
structure, the same genes are used in the early stages of their development.
To obtain a better understanding of how the activity of identical genes can
lead to the development of extremely different eye types, it is essential to
know exactly how all the relevant genes behave.



The genetic program of eye development has now been decyphered at the
Biozentrum of the University of Basel using genechips and a model organism,
the fruit fly Drosophila melanogaster. This project was made possible by the
financial support from Prof. Walter Gehring. In 2002, Prof. Gehring was
awarded the Balzan Prize for Developmental Biology and, as is stipulated in
the Balzan foundation's rules, used half of the one million Swiss Francs
prize money to fund a research project involving young scientists. Lydia
Michaut, a young collaborator of Walter Gehring, was given the opportunity
to launch this endeavour.



This project has now been completed and has generated a large amount of data
that in many respects are astounding. Large-scale analysis of gene
expression has shown that the number of genes activated in the eye increases
dramatically as an insect develops. During the larval stage, 98 genes are
specially activated for this purpose. The figure rises to 409 during the
pupal stage, and 474 in the fully grown insect.



However, it is interesting to note that the functions of the activated genes
vary considerably. Dr. Lydia Michaut, who pioneered this project, explains:
"During the larval stage, 25 percent of the genes activated for eye
development are used to regulate other genes. You could say that they
initiate the next stage in eye development. During the pupal stage, most of
the genes are used to control the creation of the eye structure and, when
the insect is fully grown, gene activity is very definitely geared towards
receiving and transmitting light stimuli."


By analysing the data in greater detail and comparing it with corresponding
measurements from mice, the scientists working on the project have shown
that Drosophila produces 1,033 proteins that are also important for eye
development in mice. These include many proteins that are only involved
during the late stages of eye development. This is a strong indication that
the eye types of insects and mice are more closely related than has
previously been thought.
















The project has lead to distinct conclusions primarily due to the large
volume of data that it produced. A special model system was used to conduct
a total of 154,000 individual measurements of genetic activities. This
system is based on the fact that there is only a single gene В¬ PAX-6 В¬ at
the outset of eye development and that insects can, in certain instances,
form eyes on extremities such as legs or antennae.



By introducing and activating PAX-6 in certain cells of the fly, Gehring's
team was able to initiate the development of eyes in places where they would
not normally be expected to grow. This is an ideal system for identifying
the genes that only occur in relation to eye development. Comparing the
differences in gene activity patterns between normal fly legs and those with
PAX-6 induced eyes reveals which genes are involved in eye development.



The 500,000 Swiss Francs in financial support provided for this project by
Prof. Gehring from his Balzan prize also enabled the team to set up a
publicly accessible database (eyebase.unibas.ch). This database
provides colleagues with free access to comprehensive data on gene activity
during eye development, thereby fulfilling the main aim of the International
Balzan Prize Foundation В¬ to promote science and culture around the world.



ABOUT THE INTERNATIONAL BALZAN PRIZE FOUNDATION


The International Balzan Prize Foundation promotes culture, the sciences and
the most meritorious initiatives in the cause of humanity, peace and
brotherhood among peoples throughout the world.



This aim is achieved through the annual presentation of four awards that
cover the following two areas: moral sciences and the arts; and physical,
mathematical and natural sciences and medicine. Each award has a prize fund
of one million Swiss Francs (approx. 610,000 Euros).



Winners are required to use half of their prize fund for research work or
studies that promote science and culture and are carried out preferably by
young humanists and scientists.



The International Balzan Prize Foundation also regularly awards a separate
special prize for Humanity, Peace and Brotherhood among Peoples.



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