characteristics of a particular cell, be it in the developing embryo
or the adult, are dictated by the expression of a set of genes
specific for that cell. In the developing C. elegans embryo,
a cascade of transcription factors operates in the development
of the mesoderm (MS) and endoderm (E) lineages. The regulatory
hierarchy begins with a maternally supplied gene product, SKN-1,
which then activates the med-1,2 genes
in the EMS cell.
At the next cell generation, MED-1,2 activate end-1,3 in
the E cell, and tbx-35 in
the MS cell. Additional inputs into end-1,3 activation
are also known.
elegans mesendoderm (or endomesoderm) Gene Regulatory
Network shares many properties with other such networks, such
as the prevalence of certain types of gene interactions (e.g.
the 'regulatory chain' or 'feed-forward' motifs). Hence, this
network is a model for gene networks in general.
We are currently evaluating
the role of other early C. elegans embryonic genes,
with the goal of constructing a comprehensive early embryo network.
We are also examining the evolution of this network in species
that are related to C. elegans.