title: Biochemical characterization of maintenance DNA methyltransferase DNMT-1 from silkworm, Bombyx mori.
abstract: DNA methylation is an important epigenetic mechanism involved in gene expression of vertebrates and invertebrates. In general, DNA methylation profile is established by de novo DNA methyltransferases (DNMT-3A, -3B) and maintainance DNA methyltransferase (DNMT-1). DNMT-1 has a strong substrate preference for hemimethylated DNA over the unmethylated one. Because the silkworm genome lacks an apparent homologue of de novo DNMT, it is still unclear that how silkworm chromosome establishes and maintains its DNA methylation profile. As the first step to unravel this enigma, we purified recombinant BmDNMT-1 using baculovirus expression system and characterized its DNA-binding and DNA methylation activity. We found that the BmDNMT-1 preferentially methylates hemimethylated DNA despite binding to both unmethylated and hemimethylated DNA. Interestingly, BmDNMT-1 formed a complex with DNA in the presence or absence of methyl group donor, S-Adenosylmethionine (AdoMet) and the AdoMet-dependent complex formation was facilitated by Zn(2+) and Mn(2+). Our results provide clear evidence that BmDNMT-1 retained the function as maintenance DNMT but its sensitivity to metal ions is different from mammalian DNMT-1.
authors.affiliation: Laboratory of Insect Genome Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Fukuoka, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Mitsudome
authors.affiliation: Laboratory of Insect Genome Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Fukuoka, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Mon
authors.affiliation: Laboratory of Insect Genome Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Fukuoka, Japan.
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
authors.affiliation: Laboratory of Insect Genome Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Fukuoka, Japan.
authors.forename: Zhiqing
authors.initials: Z
authors.lastname: Li
authors.affiliation: Laboratory of Insect Genome Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Fukuoka, Japan.
authors.forename: Jae Man
authors.initials: JM
authors.lastname: Lee
authors.affiliation: Laboratory of Insect Genome Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Fukuoka, Japan.
authors.forename: Anandrao Ashok
authors.initials: AA
authors.lastname: Patil
authors.affiliation: Laboratory of Insect Genome Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Fukuoka, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Masuda
authors.affiliation: Laboratory of Insect Pathology and Microbial Control, Institute of Biological Control, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Iiyama
authors.affiliation: Laboratory of Insect Genome Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Fukuoka, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Morokuma
authors.affiliation: Laboratory of Insect Genome Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Fukuoka, Japan. Electronic address: kusakabe@agr.kyushu-u.ac.jp.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kusakabe
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016367:Baculoviridae / Q000378:metabolism; D012831:Bombyx / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D019175:DNA Methylation; D019281:Dimerization; D007814:Larva / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins; D016415:Sequence Alignment
chemical_list: D011994:Recombinant Proteins; D004247:DNA; D004248:DNA (Cytosine-5-)-Methyltransferases
keywords: Bombyx mori; DNA methylation; DNA methyltransferase-1; Dimerization; Maintenance methylation; MspJI