Affiliation:
1. Howard Hughes Medical Institute, Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
Abstract
We have identified two genes,
smedwi-1
and
smedwi-2
, expressed in the dividing adult stem cells (neoblasts) of the planarian
Schmidtea mediterranea
. Both genes encode proteins that belong to the Argonaute/PIWI protein family and that share highest homology with those proteins defined by
Drosophila
PIWI. RNA interference (RNAi) of
smedwi-2
blocks regeneration, even though neoblasts are present, irradiation-sensitive, and capable of proliferating in response to wounding;
smedwi-2(RNAi)
neoblast progeny migrate to sites of cell turnover but, unlike normal cells, fail at replacing aged tissue. We suggest that SMEDWI-2 functions within dividing neoblasts to support the generation of cells that promote regeneration and homeostasis.
Publisher
American Association for the Advancement of Science (AAAS)