title: Lsh is involved in de novo methylation of DNA.
abstract: Deletion of Lsh perturbs DNA methylation patterns in mice yet it is unknown whether Lsh plays a direct role in the methylation process. Two types of methylation pathways have been distinguished: maintenance methylation by Dnmt1 occurring at the replication fork, and de novo methylation established by the methyltransferases Dnmt3a and Dnmt3b. Using an episomal vector in Lsh-/- embryonic fibroblasts, we demonstrate that the acquisition of DNA methylation depends on the presence of Lsh. In contrast, maintenance of previously methylated episomes does not require Lsh, implying a functional role for Lsh in the establishment of novel methylation patterns. Lsh affects Dnmt3a as well as Dnmt3b directed methylation suggesting that Lsh can cooperate with both enzymatic activities. Furthermore, we demonstrate that embryonic stem cells with reduced Lsh protein levels show a decreased ability to silence retroviral vector or to methylate endogenous genes. Finally, we demonstrate that Lsh associates with Dnmt3a or Dnmt3b but not with Dnmt1 in embryonic cells. These results suggest that the epigenetic regulator, Lsh, is directly involved in the control of de novo methylation of DNA.
authors.affiliation: Laboratory of Cancer Prevention, SAIC-FCRDC, Basic Research Program, National Cancer Institute, Frederick, MD 21701-1201, USA.
authors.forename: Heming
authors.initials: H
authors.lastname: Zhu
authors.forename: Theresa M
authors.initials: TM
authors.lastname: Geiman
authors.forename: Sichuan
authors.initials: S
authors.lastname: Xi
authors.forename: Qiong
authors.initials: Q
authors.lastname: Jiang
authors.forename: Anja
authors.initials: A
authors.lastname: Schmidtmann
authors.forename: Taiping
authors.initials: T
authors.lastname: Chen
authors.forename: En
authors.initials: E
authors.lastname: Li
authors.forename: Kathrin
authors.initials: K
authors.lastname: Muegge
mesh_terms: D000818:Animals; D015139:Blotting, Southern; D015153:Blotting, Western; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism; D004265:DNA Helicases / Q000378:metabolism / Q000502:physiology*; D019175:DNA Methylation; D000090205:DNA Methyltransferase 3A; D017931:DNA Primers; D004622:Embryo, Mammalian / Q000166:cytology; D044127:Epigenesis, Genetic / Q000502:physiology*; D005822:Genetic Vectors / Q000235:genetics; D047468:Immunoprecipitation; D051379:Mice; D018345:Mice, Knockout; D012190:Retroviridae; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000378:metabolism; D000097584:DNA Methyltransferase 3B
chemical_list: D004248:DNA (Cytosine-5-)-Methyltransferases; D004265:DNA Helicases; D000090205:DNA Methyltransferase 3A; D017931:DNA Primers; D000097584:DNA Methyltransferase 3B; C000715535:Dnmt3a protein, mouse; C491758:lymphoid specific helicase, mouse