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Journal of Biomedicine and Biotechnology
Volume 2008, Article ID 453590, 9 pages
Research Article

CFP and YFP, but Not GFP, Provide Stable Fluorescent Marking of Rat Hepatic Adult Stem Cells

Programs in Regenerative Biology and Cancer, Boston Biomedical Research Institute, Watertown, MA 02472, USA

Received 27 November 2007; Revised 10 January 2008; Accepted 2 February 2008

Academic Editor: Mouldy Sioud

Copyright © 2008 Rouzbeh R. Taghizadeh and James L. Sherley. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The stable expression of reporter genes in adult stem cells (ASCs) has important applications in stem cell biology. The ability to integrate a noncytotoxic, fluorescent reporter gene into the genome of ASCs with the capability to track ASCs and their progeny is particularly desirable for transplantation studies. The use of fluorescent proteins has greatly aided the investigations of protein and cell function on short-time scales. In contrast, the obtainment of stably expressing cell strains with low variability in expression for studies on longer-time scales is often problematic. We show that this difficulty is partly due to the cytotoxicity of a commonly used reporter, green fluorescent protein (GFP). To avoid GFP-specific toxicity effects during attempts to stably mark a rat hepatic ASC strain and, therefore, obtain stable, long-term fluorescent ASCs, we evaluated cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP), in addition to GFP. Although we were unable to derive stable GFP-expressing strains, stable fluorescent clones (up to 140 doublings) expressing either CFP or YFP were established. When fluorescently marked ASCs were induced to produce differentiated progeny cells, stable fluorescence expression was maintained. This property is essential for studies that track fluorescently marked ASCs and their differentiated progeny in transplantation studies.