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Masaki OKANO, Ph. D. 
The
development and physiological function of multicellular organisms relies
on the ability of their component individual cells, which as a rule contain
identical genetic information, to express subsets of genes in a selective
manner. In order to maintain lineages of cells of different types, the
gene expression programs established in ancestral precursor cells must
be transmitted stably to many generations of progeny. The fundamental
mechanisms by which patterns of gene expression are preserved across cycles
of cell division without a change to the underlying genome sequence are
commonly referred to as “epigenetic” processes. These processes
produce chemical modifications and structural remodeling of chromatin,
nuclear structures that store the cell's DNA, allowing individual
cells to regulate the switching on and shutting off of the expression
of specific genes with great precision and flexibility.
Our
team studies epigenetics by focusing on a particular set of molecules
that act in the methylation of DNA, with the goal of identifying their
roles in the regulation of chromatin function in embryonic development
and the processes of fate determination and plasticity in cell differentiation.
We conduct phenotype analyses of mice in which various genes involved
in DNA methylation have been knocked out, as well as biochemical and cell
biological studies of embryonic stem (ES) cells to explore how dynamic
changes in DNA methylation function as regulatory factors in mammalian
embryogenesis and cell differentiation, and the means by which DNA methylation
works to maintain cell proliferation and chromosome function. We anticipate
that a deeper understanding of these questions will lead to new insights
in the context-specificity of the DNA methylation process as well as the
roles of methylation in development, health and regeneration.
