Distinct processes and transcriptional targets underlie CDX2 requirements in intestinal stem cells and differentiated villus cells
San Roman, A.K., Tovaglieri, A., Breault, D.T., and Shivdasani, R.A. (2015) Stem Cell Rep. 5: 673-81.
Abstract: Lgr5-expressing intestinal stem cells (ISCs) renew the adult gut epithelium by producing mature villus cells (VCs); the transcriptional basis for ISC functions remains unclear. RNA sequencing analysis identified transcripts modulated during differentiation of Lgr5+ ISCs into VCs, with high expression of the intestine-restricted transcription factor (TF) gene Cdx2 in both populations. Cdx2-deleted mouse ISCs showed impaired proliferation and long-term inability to produce mature lineages, revealing essential ISC functions. Chromatin immunoprecipitation sequencing analysis of CDX2 in Lgr5+ ISCs, coupled with mRNA profiling of control and Cdx2−/− ISCs, identified features of CDX2 regulation distinct from VCs. Most CDX2 binding in ISCs occurs in anticipation of future gene expression, but whereas CDX2 primarily activates VC genes, direct ISC targets are activated and repressed. Diverse CDX2 requirements in stem and differentiated cells may reflect the versatility of TFs that specify a tissue in development and control the same tissue in adults.
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