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Wnt signaling maintains the undifferentiated state of intestinal crypt progenitor cells by inducing the formation of nuclear TCF4/β-catenin complexes. In colorectal cancer, activating mutations in Wnt pathway components cause inappropriate activation of TCF4/β-catenin-driven transcription. Despite the passage of a decade after the discovery of TCF4 and β-catenin as the molecular effectors of the Wnt signal, few transcriptional activators essential and unique to the regulation of this transcription program have been found. Using proteomics, we identified the leukemia-associated Mllt10/Af10 and the methyltransferase Dot1l as Tcf4/β-catenin interactors in mouse small intestinal crypts. Mllt10/Af10-Dot1l, essential for transcription elongation, are recruited to Wnt target genes in a β-catenin-dependent manner, resulting in H3K79 methylation over their coding regions in vivo in proliferative crypts of mouse small intestine in colorectal cancer and Wnt-inducible HEK293T cells. Depletion of MLLT10/AF10 in colorectal cancer and Wnt-inducible HEK293T cells followed by expression array analysis identifies MLLT10/AF10 and DOT1L as essential activators to a large extent dedicated to Wnt target gene regulation. In contrast, previously published β-catenin coactivators p300 and BRG1 displayed a more pleiotropic target gene expression profile controlling Wnt and other pathways. tcf4, mllt10/af10, and dot1l are co-expressed in Wnt-driven tissues in zebrafish and essential for Wnt-reporter activity. Intestinal differentiation defects in apc-mutant zebrafish can be rescued by depletion of Mllt10 and Dot1l, establishing these genes as activators downstream of Apc in Wnt target gene activation in vivo. Morpholino-depletion of mllt10/af10-dot1l in zebrafish results in defects in intestinal homeostasis and a significant reduction in the in vivo expression of direct Wnt target genes and in the number of proliferative intestinal epithelial cells. We conclude that Mllt10/Af10-Dot1l are essential, largely dedicated activators of Wnt-dependent transcription, critical for maintenance of intestinal proliferation and homeostasis. The methyltransferase DOT1L may present an attractive candidate for drug targeting in colorectal cancer.
Pubmed ID: 21103407 RIS Download
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A collection of both commercial and noncommercial software products which includes: Mascot Distiller, Mascot Parser, and Mascot Server. Mascot Distiller is commercial and provides a single interface to process raw data into de-isotoped peak lists. This tool can also be used for the easy distribution of search and quantitative results to colleagues. The non-commercial Mascot Parser software provides an API (Application Programmer Interface) that makes it easier to access search results written in C++, Java, Python and Perl. Mascot Server is non-commercial, and is a collection of peptide mass fingerprints as well as a MS/MS database. A selection of popular sequence databases are available online and include SwissProt, NCBInr, and the EST divisions of EMBL. This server is best used for evaluating and searching for smaller data sets.
View all literature mentionsCollection of genome databases for vertebrates and other eukaryotic species with DNA and protein sequence search capabilities. Used to automatically annotate genome, integrate this annotation with other available biological data and make data publicly available via web. Ensembl tools include BLAST, BLAT, BioMart and the Variant Effect Predictor (VEP) for all supported species.
View all literature mentionsA contract research organization providing drug development and animal testing services. Under the name Covance Research Products Inc., based in Denver, Pennsylvania, the company also deals in the import, breeding and sale of laboratory animals. It breeds dogs, rabbits, guinea pigs, non-human primates, and pigs, and runs the largest non-human primate laboratory in Germany. (Wikipedia)
View all literature mentionsCell line HEK293T is a Transformed cell line with a species of origin Homo sapiens (Human)
View all literature mentionsCell line LS174T is a Cancer cell line with a species of origin Homo sapiens (Human)
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