1. Tracking Down the Stem Cells of the Intestine: Strategies to Identify Adult Stem Cells 
Nick Barker, Hans Clevers 
Gastroenterology 
Volume 133, Issue 6, Pages (December 2007)
DOI: /j.gastro
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2. Figure 1
CBC cells located at the crypt base in the small intestine. (A) Electron microscopy identifies the CBC cells as small, slender cells interspersed between the Paneth cells. (Reprinted with permission from Cheng H, Leblond CP. Origin, differentiation and renewal of the 4 main epithelial cell types in the mouse small intestine. I. Columnar cell. Am J Anat 1974;141:461–479.) (B) Leblond, Cheng, and Bjerknes proposed that CBC cells are likely to be the origin of the various cell types on the small intestinal epithelium. (Adapted from Cheng H, Leblond CP. Origin, differentiation and renewal of the 4 main epithelial cell types in the mouse small intestine. V. Unitarian Theory of the origin of the 4 epithelial cell types. Am J Anat 1974;141:537–561.)
Gastroenterology  , DOI: ( /j.gastro )
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3. Figure 2
Lgr5/Gpr49 is an orphan G-protein coupled receptor related to the glycoprotein hormone receptors LHR, FSHR, and TSHR. (A) Predicted structure of Lgr5, comprising a large amino-terminal extracellular domain containing leucine-rich repeats for ligand interaction, a 7-transmembrane domain, and a short c-terminal domain for signal transduction. (B) The phylogenetic relationship between Lgr5 and family members (reproduced with permission from Luo CW, Hsueh AJ. Genomic analyses of the evolution of LGR genes. Chang Gung Med J 2006;29:2–8).31 Although Bursicon has been identified as the ligand for Drosophila LGR2, there are currently no known ligands for the remaining group B receptors Lgr4, Lgr5, and Lgr6.
Gastroenterology  , DOI: ( /j.gastro )
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4. Figure 3
Lgr5 expression is restricted to the CBC cells of the small intestine. (A) GFP expression in CBC cells of Lgr5-EGFP knock-in mice. (B) LacZ expression in CBC cells of Lgr5-LacZ knock-in mice. (C) Cartoon depicting the presence of 4-6 Lgr5-positive CBC cells intermingled with the Paneth cells at the base of the small intestinal crypts.
Gastroenterology  , DOI: ( /j.gastro )
Copyright © 2007 AGA Institute Terms and Conditions

5. Figure 4
Whole-mount photograph of small intestine from Lgr5-EGFP-Ires-CreERT2/Rosa26-LacZ mice induced for 5 days with low-dose tamoxifen. The ribbon of blue cells extending from the crypt (outlined) to the tip of the villus demonstrates that Lgr5-positive CBC cells are capable of generating the entire villus epithelium. Similar observations at much later time points (60 days postinduction) prove that the Lgr5-positive CBC cells are multipotent and long lived, allowing us to conclude that they are the true stem cells of the intestine.
Gastroenterology  , DOI: ( /j.gastro )
Copyright © 2007 AGA Institute Terms and Conditions