Open AccessSpontaneous Fusion and Nonclonal Growth of Adult Neural Stem Cells
Author(s) -
Jessberger Sebastian,
Clemenson Gregory D.,
Gage Fred H.
Publication year - 2007
Publication title -
stem cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.159
H-Index - 229
eISSN - 1549-4918
pISSN - 1066-5099
DOI - 10.1634/stemcells.2006-0620
Subject(s) - neurosphere , biology , cell sorting , green fluorescent protein , neural stem cell , microbiology and biotechnology , fusion protein , in vitro , stem cell , neurogenesis , adult stem cell , flow cytometry , recombinant dna , endothelial stem cell , gene , genetics
Multipotent neural stem cells (NSCs) can be isolated from various regions of the adult brain and propagated in vitro. Recent reports have suggested spontaneous fusion events among NSCs when grown as free‐floating neurospheres that may affect the genetic composition of NSC cultures. We used adult NSCs expressing either red fluorescent protein (RFP) or green fluorescent protein (GFP) to analyze the fusion frequency of rat and mouse NSCs. Fluorescence‐activated cell sorting (FACS) revealed that, under proliferating conditions, approximately 0.2% of rat and mouse NSCs coexpressed RFP and GFP irrespective of whether the cells were grown as neurospheres (mouse NSCs) or as attached monolayers (rat and mouse NSCs). Fused cells did not proliferate and could not be propagated, suggesting that aberrantly fused cells are not viable. Furthermore, we found that neither neurospheres nor monolayers grew clonally, because even very low‐density cultures had spheres containing both GFP‐ and RFP‐expressing cells and monolayer patches with GFP‐ and RFP‐expressing cells in close proximity. The nonclonal growth between distinct NSC populations strongly suggests the use of careful and precise culture conditions, such as single‐cell assays, to characterize potency and growth of NSCs in vitro. Disclosure of potential conflicts of interest is found at the end of this article.