title: Efficient translation of Dnmt1 requires cytoplasmic polyadenylation and Musashi binding elements.
abstract: Regulation of DNMT1 is critical for epigenetic control of many genes and for genome stability. Using phylogenetic analysis we characterized a block of 27 nucleotides in the 3'UTR of Dnmt1 mRNA identical between humans and Xenopus and investigated the role of the individual elements contained within it. This region contains a cytoplasmic polyadenylation element (CPE) and a Musashi binding element (MBE), with CPE binding protein 1 (CPEB1) known to bind to the former in mouse oocytes. The presence of these elements usually indicates translational control by elongation and shortening of the poly(A) tail in the cytoplasm of the oocyte and in some somatic cell types. We demonstrate for the first time cytoplasmic polyadenylation of Dnmt1 during periods of oocyte growth in mouse and during oocyte activation in Xenopus. Furthermore we show by RNA immunoprecipitation that Musashi1 (MSI1) binds to the MBE and that this element is required for polyadenylation in oocytes. As well as a role in oocytes, site-directed mutagenesis and reporter assays confirm that mutation of either the MBE or CPE reduce DNMT1 translation in somatic cells, but likely act in the same pathway: deletion of the whole conserved region has more severe effects on translation in both ES and differentiated cells. In adult cells lacking MSI1 there is a greater dependency on the CPE, with depletion of CPEB1 or CPEB4 by RNAi resulting in substantially reduced levels of endogenous DNMT1 protein and concurrent upregulation of the well characterised CPEB target mRNA cyclin B1. Our findings demonstrate that CPE- and MBE-mediated translation regulate DNMT1 expression, representing a novel mechanism of post-transcriptional control for this gene.
authors.affiliation: Transcriptional Regulation and Epigenetics Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, North Ireland, United Kingdom.
authors.forename: Charlotte E
authors.initials: CE
authors.lastname: Rutledge
authors.affiliation: Transcriptional Regulation and Epigenetics Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, North Ireland, United Kingdom.
authors.forename: Ho-Tak
authors.initials: HT
authors.lastname: Lau
authors.affiliation: Transcriptional Regulation and Epigenetics Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, North Ireland, United Kingdom.
authors.forename: Hazel
authors.initials: H
authors.lastname: Mangan
authors.affiliation: Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America.
authors.forename: Linda L
authors.initials: LL
authors.lastname: Hardy
authors.affiliation: Transcriptional Regulation and Epigenetics Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, North Ireland, United Kingdom.
authors.forename: Olaf
authors.initials: O
authors.lastname: Sunnotel
authors.affiliation: The State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Guo
authors.affiliation: Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America.
authors.forename: Angus M
authors.initials: AM
authors.lastname: MacNicol
authors.affiliation: Transcriptional Regulation and Epigenetics Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, North Ireland, United Kingdom.
authors.forename: Colum P
authors.initials: CP
authors.lastname: Walsh
authors.affiliation: Transcriptional Regulation and Epigenetics Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, North Ireland, United Kingdom.
authors.forename: Diane J
authors.initials: DJ
authors.lastname: Lees-Murdock
mesh_terms: D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D015153:Blotting, Western; D002645:Chickens; D003593:Cytoplasm / Q000378:metabolism; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics* / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D005822:Genetic Vectors / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D009865:Oocytes / Q000254:growth & development / Q000378:metabolism; D010802:Phylogeny; D026723:Polyadenylation / Q000235:genetics*; D014176:Protein Biosynthesis / Q000235:genetics*; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014981:Xenopus; D015027:Zebrafish
chemical_list: D017931:DNA Primers; C104786:Msi1h protein, mouse; D009419:Nerve Tissue Proteins; D016601:RNA-Binding Proteins; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619380:DNMT1 protein, human; C000619381:Dnmt1 protein, mouse; C000619382:Dnmt1 protein, rat