The broad goal of the research in my laboratory is
to characterize the cellular and molecular basis of
morphogenesis. Using gonadal development in the mouse
as the model system, we investigate how Sry, the male
sex-determining gene, controls the development of
a testis. Gonad development is unique in that a single
rudimentary tissue can be induced to form one of two
different organs, an ovary or testis. Sex determination
is the step at which the gonad and its store of germ
cells initiate male or female development. During
my postdoc, I was involved in the discovery of Sry,
the Y-linked gene that controls the choice between
these two fates in the bipotential gonad. If Sry is
expressed in the rudimentary gonad, either from the
Y chromosome or from an ectopic transgene, a testis
forms. If Sry is not expressed, as in XX mice, an
ovary forms. This system provides a rare opportunity
to identify molecular and cellular pathways linking
the expression of a pivotal gene in development, with
morphogenetic mechanisms that operate to pattern the
development of an organ and the differentiation of
its cells. Our assays have revealed that Sry initiates
multiple signaling pathways required for morphogenetic
divergence along the male pathway, including those
that direct proliferation, cell migration, and germ
cell/somatic cell organization. Many approaches are
used to characterize differences between male and
female gonads, including RNA in situ hybridization,
microarray analysis, and immunocytochemistry. Genetic
and biochemical approaches as well as novel organ
culture methods are used to identify the signals that
control these processes and to experimentally determine
their role during organogenesis of the testis. Current
Projects: Specific projects include live imaging work
on vascularization, genetic control of proliferation
and migration, cell fate determination, and germline
stem cell development. We have also initiated a project
to explore temperature-dependent sex determination
in the red-eared slider turtle, T.scripta.
