The leukemia-associated Mllt10/Af10-Dot1l are Tcf4/β-catenin coactivators essential for intestinal homeostasis
| Autor: | Robert G.J. Vries, Albert J. R. Heck, Pantelis Hatzis, Tokameh Mahmoudi, Nadia Taouatas, Vivian S. W. Li, Hans Clevers, Hans Teunissen, Sylvia F. Boj, Harry Begthel, Jeroen Korving, Shabaz Mohammed |
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| Přispěvatelé: | Hubrecht Institute for Developmental Biology and Stem Cell Research |
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Beta-catenin
Transcription Genetic QH301-705.5 Oncology/Gastrointestinal Cancers Gastroenterology and Hepatology/Small Intestine General Biochemistry Genetics and Molecular Biology Cell Line Mice Transcription Factor 4 Intestine Small Animals Homeostasis Humans Biology (General) Transcription factor Cell Biology/Gene Expression Zebrafish beta Catenin Cell Proliferation Regulation of gene expression Leukemia General Immunology and Microbiology biology Basic Helix-Loop-Helix Leucine Zipper Transcription Factors Reverse Transcriptase Polymerase Chain Reaction General Neuroscience Molecular Biology/Transcription Elongation Wnt signaling pathway Correction LRP6 LRP5 Histone-Lysine N-Methyltransferase Methyltransferases DNA Methylation Developmental Biology/Stem Cells Catenin DNA methylation Cancer research biology.protein General Agricultural and Biological Sciences Biochemistry/Transcription and Translation Research Article Transcription Factors |
| Zdroj: | PLoS Biology, 8(11). Public Library of Science PLoS Biology PLoS Biology, Vol 8, Iss 11, p e1000539 (2010) |
| ISSN: | 1544-9173 |
| DOI: | 10.1371/journal.pbio.1000539 |
| Popis: | The leukemia-associated Mllt10/Af10 and its partner the histone methyltransferase Dot1l are identified as Tcf4/β-catenin co-activators and shown to be essential for Wnt-driven endogenous gene expression, intestinal development and homeostasis. 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. Author Summary The canonical Wnt pathway is a key regulatory pathway controlling intestinal cell proliferation, differentiation, and stem cell maintenance, and its deregulation leads to malignancies in the mammalian gut. A decade has passed since the discovery of the transcription factors TCF4-β-catenin as the downstream intestinal molecular effectors of Wnt, but few transcriptional activators essential and unique to the regulation of this transcription program have been found. In this study, using a proteomics approach, we identify the leukemia-associated Mllt10/Af10 and its partner the histone methyltransferase Dot1l as interactors with Tcf4/β-catenin in the mouse small intestinal epithelium. We demonstrate that Mllt10/Af10–Dot1l are recruited to Wnt target genes in intestinal epithelial cells and are essential to regulate expression of these targets. We also show a genetic link between the Wnt pathway and Mllt10/Af10-Dot1l in zebrafish and delineate their essential role in Wnt-driven endogenous gene expression. Finally, we demonstrate the physiological role of Mllt10/Af10-Dot1l in Wnt-driven intestinal development and homeostasis; depletion of Mllt10/Af10-Dot1l in zebrafish embryos mimics the Tcf4-depleted phenotype in which significant intestinal proliferation defects accompany a decrease in total number of intestinal cells. We conclude that the enzyme Dot1l may present an attractive candidate for drug targeting in colorectal cancer. |
| Databáze: | OpenAIRE |
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