Stem cell populations exist in "niches" that hold them and regulate their fate decisions. Identification and characterization of these niches is essential for understanding stem cell maintenance and tissue regeneration. Here we report on the identification of a novel stem cell niche in Botryllus schlosseri, a colonial urochordate with high stem cell-mediated developmental activities. Using in vivo cell labeling, engraftment, confocal microscopy, and time-lapse imaging, we have identified cells with stemness capabilities in the anterior ventral region of the Botryllus' endostyle. These cells proliferate and migrate to regenerating organs in developing buds and buds of chimeric partners but do not contribute to the germ line. When cells are transplanted from the endostyle region, they contribute to tissue development and induce long-term chimerism in allogeneic tissues. In contrast, cells from other Botryllus' regions do not show comparable stemness capabilities. Cumulatively, these results define the Botryllus' endostyle region as an adult somatic stem cell niche.
Bibliographical noteFunding Information:
We thank Amir Voskoboynik, T. Raveh, and A. De Tomaso for critical review, and P. Brown, R. Marinelli, R. Pesich L. Jerabek, C. Patton, K. Lee, and R. Will for generous support and helpful assistance. This study was supported by USPHS grant DK54762 and to a minor extent by HL58770 by a grant from the US-Israel Binational Science Foundation (2003-010) and by the Israel Science Foundation (project 550-06).
ASJC Scopus subject areas
- Molecular Medicine
- Cell Biology