PASADENA, Calif.During the early developmental stages of vertebratesanimals that have a backbone and spinal column, including humanscells undergo extensive rearrangements, and some cells migrate over large distances to populate particular areas and assume novel roles as differentiated cell types. Understanding how and when such cells switch their purpose in an embryo is an important and complex goal for developmental biologists. A recent study, led by researchers at the California Institute of Technology (Caltech), provides new clues about this processat least in the case of neural crest cells, which give rise to most of the peripheral nervous system, to pigment cells, and to large portions of the facial skeleton.
"There has been a long-standing mystery regarding why some cells in the developing embryo start out as part of the future central nervous system, but leave to populate peripheral parts of the body," says Marianne Bronner, the Albert Billings Ruddock Professor of Biology at Caltech and corresponding author of the paper, published in the November 1 issue of the journal Genes & Development. "In this paper, we find that an important type of enzyme called DNA-methyltransferase, or DNMT, acts as a switch, determining which cells will remain part of the central nervous system, and which will become neural crest cells."
According to Bronner, DNMT arranges this transition by silencing expression of the genes that promote central nervous system (CNS) identity, thereby giving the cells the green light to become neural crest, migrate, and do new things, like help build a jaw bone. The team came to this conclusion after analyzing the actions of one type of DNMTDNMT3Aat different stages of development in a chicken embryo.
This is important, says Bronner, because while most scientists who study the function of DNMTs use embryonic stem cells that can be maintained in culture, her team is "studying events that occur in living embryo
|Contact: Caltech Media Relations|
California Institute of Technology