Karrer Kathleen M, VanNuland Teresa A
Department of Biology, Wehr Life Sciences, Marquette University, PO Box 1881, Milwaukee, WI 53201-1881, USA.
Nucleic Acids Res. 2002 Mar 15;30(6):1364-70. doi: 10.1093/nar/30.6.1364.
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.
纤毛原生动物四膜虫的体大核中,每条染色体约有50个拷贝:四膜虫大核DNA中约0.8%的腺嘌呤残基被甲基化为N6-甲基腺嘌呤。甲基化程度在不同位点之间有所不同,从非常低的百分比到>90%。在本研究中,发现核小体定位与DNA甲基化之间存在相关性。研究了8个具有不同甲基化水平的GATC位点。这些位点的甲基化程度与靠近连接DNA的程度之间存在直接相关性。尽管甲基化优先发生在连接DNA中,但组蛋白H1基因敲除菌株中的甲基化模式和程度与野生型细胞中的几乎无法区分。