MEDFORD/SOMERVILLE, Mass. (March 15, 2012) -- The genetic pathway that regulates the way cells align themselves relative to each other has been found to act as a "stop sign" that signals organisms when to halt cell growth, according to new research published by biologists at the Center for Regenerative and Developmental Biology in Tufts University's School of Arts and Sciences.
The research, available in Stem Cells and Development online in advance of final editing, sheds light on one of the primary challenges to developing new ways to induce regenerative repair: discovering how new tissue knows when to stop growing.
"The planar cell polarity (PCP) pathway is known to control alignment of cells within the organism, and errors in PCP result in a variety of syndromes," said Michael L. Levin, Ph.D., senior author on the paper and director of the Center. "We found that this pathway also acts as a signal that we can target to induce continued growth of nerve tissue during regeneration."
The researchers reported that in planarian flatworms, an important model of regeneration, inhibition of one or all of the Vangl2, DAAM1, and ROCK genes in the PCP pathway resulted in excess growth of the central nervous system, as well as extra eyes and excess optical neurons.
The Tufts biologists also found that PCP played a similar signaling role in vertebrates. Loss of Vangl2 led to overgrowth of neural tissue in Xenopus tadpoles during both normal development and tail regeneration.
Tissue growth is central to many biological processes, including embryonic development, routine cell replacement and regeneration following injury or disease. During tissue growth, stem and progenitor cells must be integrated and aligned with surrounding tissues and cells, and tissues must sense when that growth is complete. When such growth is not carefully controlled, the results can be disastrous.
"Right now very little is know
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