Reference : Feedback Loop Between The Liver-Enriched Transcription Factor Network and Mir-122 Contro...
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
Human health sciences : Gastroenterology & hepatology
http://hdl.handle.net/2268/102260
Feedback Loop Between The Liver-Enriched Transcription Factor Network and Mir-122 Controls Hepatocyte Differentiation.
English
Peers, Bernard mailto [Université de Liège - ULg > Département des sciences de la vie > GIGA-R : Biologie et génétique moléculaire >]
Manfroid, Isabelle mailto [Université de Liège - ULg > > GIGA-Research >]
Laudadio, Ilaria [ > > ]
12-Sep-2011
Gastroenterology
W.B. Saunders
International
0016-5085
1528-0012
Philadelphia
PA
[en] microRNA ; hepatocyte differentiation ; liver
[en] Hepatocyte differentiation is controlled by a network of liver-enriched transcription factors (LETFs). Here we investigated whether LETFs control microRNA expression during development, and whether such control is required for hepatocyte differentiation. Methods. Using in vivo DNA-binding assays we identified miR-122 as a direct target of the LETF Hepatocyte Nuclear Factor (HNF) 6. The role and mechanism of the HNF6 - miR-122 gene cascade in hepatocyte differentiation was studied in vivo and in vitro by gain- and loss-function experiments using the developing mouse and zebrafish as model organisms. Results. HNF6 and its paralog Onecut2 are potent transcriptional stimulators of miR-122 expression during liver development. Conversely, accurate levels of miR-122 are required to ensure proper progression of hepatocyte differentiation. MiR-122 exerts this function by stimulating the expression of hepatocyte-specific genes and of most LETFs, including HNF6. This reveals the existence of a HNF6 – miR-122 positive feedback loop. Moreover, stimulation of hepatocyte differentiation by miR-122 is abolished in an HNF6-null background, revealing that a transcription factor can mediate microRNA function. Confirming direct regulation, all hepatocyte-specific genes whose expression is stimulated by miR-122 are occupied in vivo by HNF6. Conclusions. Our findings reveal a novel control of hepatocyte differentiation, which is directed by a positive feedback loop between a transcription factor and a microRNA, both being specifically expressed in liver. This work also bears significance for in vitro programmed differentiation of hepatocytes and for understanding dedifferentiation in pathological conditions.
Giga-Development and Stem Cells
fédéral
ARC "Mir-age"
http://hdl.handle.net/2268/102260

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