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BACKGROUND: Canonical Wnt pathway signaling is necessary for maintaining the proliferative capacity of mammalian intestinal crypt base columnar stem cells (CBCs). Furthermore, dysregulation of the Wnt pathway is a major contributor to disease, including oncogenic transformation of the intestinal epithelium. Given the critical importance of this pathway, numerous tools have been used as proxy measures for Wnt pathway activity, yet the relationship between Wnt target gene expression and reporter allele activity within individual cells at the crypt base remains unclear.
RESULTS: Here, we describe a novel Axin2-CreERT2-tdTomato allele that efficiently marks both WntHigh CBCs and radioresistant reserve intestinal stem cells. We analyze the molecular and functional identity of Axin2-CreERT2-tdTomato-marked cells using single cell gene expression profiling and tissue regeneration assays and find that Axin2 reporter activity does not necessarily correlate with expression of Wnt target genes and, furthermore, that Wnt target genes themselves vary in their expression patterns at the crypt base.
CONCLUSIONS: Wnt target genes and reporter alleles can vary greatly in their cell-type specificity, demonstrating that these proxies cannot be used interchangeably. Furthermore, Axin2-CreERT2-tdTomato is a robust marker of both active and reserve intestinal stem cells and is thus useful for understanding the intestinal stem cell compartment.
This is the peer reviewed version of the following article: [Li, N., Yousefi, M., Nakauka-Ddamba, A., Tobias, J.W., Jense, S.T., Morrisey, E.E., & Lengner, C.J. Heterogeneity in Readouts of Canoncial Wnt Pathway Activity within Instestinal Crypts. Developmental Dynamics 245, no. 8: pp. 822-833], which has been published in final form at http://dx.doi.org/10.1002/dvdy.24423. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.
crypt base columnar stem cells, quiescent stem cells, reserve stem cells, Wnt signaling, Bmi1, Hopx, Lgr5, intestine
Li, N., Yousefi, M., Nakauka-Ddamba, A., Tobias, J. W., Jensen, S. T., Morrisey, E. E., & Lengner, C. J. (2016). Heterogeneity in Readouts of Canonical Wnt Pathway Activity within Intestinal Crypts. Developmental Dynamics, 245 (8), 822-833. http://dx.doi.org/10.1002/dvdy.24423
Date Posted: 25 October 2018
This document has been peer reviewed.