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Raj LADHER, Ph. D. 
Organogenesis
is a monumental undertaking. From situating a given organ at its correct
location, to confirming that it is correctly engineered and constructed,
to ensuring the necessary functional connections with other organs, the
embryo has a daunting task before it; indeed, perhaps we should be surprised
that the result is so frequently successful. Taking sensory organogenesis
as our model system, we hope to be able to follow the route an organ takes
in its development, and seek to understand the steps that allow it to
reach maturity. One aim is to be able to recapitulate these steps in vitro,
with the ultimate goal of providing potentially clinically relevant applications.
The
ear provides a particularly rich system for study. The inner ear, which
converts mechanical stimulation to electrical impulses, is formed from
a piece of tissue originally destined to become skin; a fate altered by
instructive signals in a process known as induction. In our research to
date, we have identified the mechanism and the signals that set this early
tissue on its path toward an inner ear fate as well as those that determine
its position. We next hope to learn how these signals are themselves established.
We are also investigating the role these signals play in the regulated
differentiation of the otic placode, and in better understanding the cellular,
molecular and embryological process responsible for this elegantly engineered
organ of hearing.
The
inner ear cannot function alone. In higher vertebrates, it requires the
middle ear to transduce sound that has been channeled through the external
ear, as well as specialized regions within the brain to interpret the
information it sends. But how is this intricate integration achieved?
Using a combination of molecular and embryological techniques, we are
characterizing the systems the embryo uses in the coordinated construction
of the auditory apparatus.
We
believe that an understanding of the embryological systems that control
the development of the inner ear can be applied to the development of
other organs, sensory organs in particular. By working to comprehend the
induction and development of other sense organs, such as the olfactory
system and the eye, we are now taking steps toward achieving insights
into common mechanisms underpinning the development of organ systems.
