Methylation of adenine in the nuclear DNA of Tetrahymena is internucleosomal and independent of histone H1.
There are about 50 copies of each chromosome in the somatic macronucleus of the ciliated protozoan TETRAHYMENA: Approximately 0.8% of the adenine residues in the macronuclear DNA of Tetrahymena are methylated to N6-methyladenine. The degree of methylation varies between sites from a very low percentage to >90%. In this study a correlation was found between nucleosome positioning and DNA methylation. Eight GATC sites with different levels of methylation were examined. There was a direct correlation between the degree of methylation and proximity to linker DNA at these sites. Although methylation occurs preferentially in linker DNA, the patterns and extent of methylation in a histone H1 knockout strain were virtually indistinguishable from those in wild-type cells.
Karrer
Kathleen M
KM
Department of Biology, Wehr Life Sciences, Marquette University, PO Box 1881, Milwaukee, WI 53201-1881, USA. kathleen.karrer@marquette.edu
VanNuland
Teresa A
TA
D000225:Adenine / Q000031:analogs & derivatives* / Q000378:metabolism*; D000227:Adenine Nucleotides / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D019175:DNA Methylation; D016054:DNA, Protozoan / Q000378:metabolism*; D017353:Gene Deletion; D006657:Histones / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D009707:Nucleosomes / Q000378:metabolism*; D013768:Tetrahymena / Q000235:genetics* / Q000378:metabolism
D000225:Adenine; D000227:Adenine Nucleotides; D016054:DNA, Protozoan; D006657:Histones; D009707:Nucleosomes; C000730567:6-methyladenine