title: miR-145 directs intestinal maturation in zebrafish.
abstract: The rapid specification and differentiation of the embryonic zebrafish gut is essential to provide contractility for the digestion of food. The role of microRNAs in modulating gut epithelial or smooth muscle differentiation is currently not known. Here we show that the microRNA miR-145 is strongly expressed in zebrafish gut smooth muscle and regulates its development. Modulation of miR-145 levels results in gut smooth muscle and epithelium maturation defects. Loss of miR-145 results in defects of smooth muscle function as measured by decreased nitric oxide production but also leads to increased expression of the embryonic smooth muscle markers sm22alpha-b, nm-mhc-b, and smoothelin. Defects in gut epithelial maturation are also present as observed by immature morphology and a complete loss of alkaline phosphatase expression. Loss or gain of miR-145 function phenocopies defects observed with altered gata6 expression and accordingly, we show that miR-145 directly represses gata6, and that gata6 is a major miR-145 target in vitro and in vivo. miR-145 therefore plays a critical role in promoting the maturation of both layers of the gut during development through regulation of gata6.
authors.affiliation: Biochemistry and Molecular Biology, and Smooth Muscle Research Group, University of Calgary, Calgary, AB, Canada T2N 4N1.
authors.forename: Lei
authors.initials: L
authors.lastname: Zeng
authors.forename: Alyson D
authors.initials: AD
authors.lastname: Carter
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Childs
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics / Q000502:physiology; D000818:Animals; D030801:Animals, Genetically Modified; D001665:Binding Sites / Q000235:genetics; D050980:GATA Transcription Factors / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins / Q000235:genetics; D006321:Heart / Q000196:embryology; D017403:In Situ Hybridization; D007413:Intestinal Mucosa / Q000196:embryology / Q000378:metabolism; D007422:Intestines / Q000196:embryology*; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D009130:Muscle, Smooth / Q000196:embryology / Q000378:metabolism; D016376:Oligonucleotides, Antisense / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; D050980:GATA Transcription Factors; C525956:Gata6 protein, zebrafish; D035683:MicroRNAs; C544858:Mirn145 microRNA, zebrafish; D016376:Oligonucleotides, Antisense; D011994:Recombinant Proteins; D029961:Zebrafish Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins