Opposing ball clubs don't take the field at the same time, and
neither do teams of proteins responsible for creating the eye.
While one team builds the retina, in adjacent cellular turf the
opponents are busy constructing the cord that carries visual
signals to the brain. And these guys aren't supposed to mingle.
That's why researchers at the Salk Institute for Biological
Studies were surprised to find the respective team captains--
Vax2, a protein that along with Vax1 builds the optic nerve
cord, and Pax6, a protein that drives retinal fate--playing on
the same field. That puzzle is explained in a forthcoming paper
in Genes and Development. Earlier studies from the laboratory of
Greg Lemke, Ph.D., professor in Salk's Molecular Neurobiology
Laboratory, had shown that Vax2 antagonized Pax6. "We knew that
Vax1 and 2 acted together to inactivate Pax6. That's how you get
an optic nerve--by preventing it from becoming a retina,"
explains Lemke. The only problem was that later on both Vax2 and
Pax6 were co-expressed