title: Chlorella virus SC-1A encodes at least five functional and one nonfunctional DNA methyltransferases.
abstract: Chlorella virus SC-1A encodes at least six DNA methyltransferases (MTases): four N6-methyldeoxyadenine (m6A) MTases, M x CviSI (TGCmA), M x CviSII (CmATG), M x CviSIII (TCGmA) and M x CviSIV (GmATC), one 5-methyldeoxycytosine (m5C) MTase, M x CviSV (approximately RCmCG), and one nonfunctional m5C MTase, M x CviSVI, which is homologous to the MTase M x CviJI [RGmC(T/C/G)] produced by another chlorella virus IL-3A. Genes encoding three of the SC-1A m6A MTases (M x CviSI, M x CviSII, and M x CviSIII) and the nonfunctional m5C MTase were cloned and sequenced. Neither M x CviSI nor M x CviSIII genes hybridized to genes for their respective isomethylomers, M x CviRI and M x CviBIII, from other chlorella viruses. However, the M x CviSII gene hybridized strongly to its M x CviAII isomethylomer gene from virus PBCV-1. Like the prototype chlorella virus PBCV-1, the SC-1A genome contains inverted terminal repeats, one of which is adjacent to the nonfunctional m5C MTase. The three cloned m6A MTase genes are distributed throughout the approx. 345 kb SC-1A genome.
authors.affiliation: Department of Plant Pathology, University of Nebraska, Lincoln 68583-0722, USA.
authors.forename: Q
authors.initials: Q
authors.lastname: Que
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.forename: M
authors.initials: M
authors.lastname: Nelson
authors.forename: S
authors.initials: S
authors.lastname: Ropp
authors.forename: D E
authors.initials: DE
authors.lastname: Burbank
authors.forename: J L
authors.initials: JL
authors.lastname: Van Etten
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002708:Chlorella / Q000201:enzymology / Q000821:virology; D003001:Cloning, Molecular; D019175:DNA Methylation; D015254:DNA Modification Methylases; D004279:DNA, Viral / Q000378:metabolism*; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010641:Phenotype; D017862:Phycodnaviridae / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D004279:DNA, Viral; D015254:DNA Modification Methylases; D008780:Methyltransferases; C066168:mRNA(adenine-N6)-methyltransferase; D015252:Deoxyribonucleases, Type II Site-Specific