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Methylation of adenine in the nuclear DNA of Tetrahymena is internucleosomal and independent of histone H1.

ABSTRACT: 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.

SUBMITTER: Karrer KM

PROVIDER: S-EPMC101364 | biostudies-literature | 2002 Mar

REPOSITORIES: biostudies-literature

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Methylation of adenine in the nuclear DNA of Tetrahymena is internucleosomal and independent of histone H1.

Karrer Kathleen M KM VanNuland Teresa A TA

Nucleic acids research 20020301 6

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 correlati ...[more]

PMID: 11884634

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