Deoxyribonucleic acid methylase of mammalian tissues

Sheid, Bertrum; Pr, Srinivasan; Borek, Ernest

doi:10.1021/bi00841a034

Cited by 83 publications

(18 citation statements)

References 5 publications

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“…However, there have been reports suggesting that chromatin proteins can prevent the methylation of potentially methylatable sites by non-homologous DNA methyltransferases (16,17). Since it is known that DNA methyltransferase is tightly bound to DNA in the nuclei of mammalian cells (18), we reasoned that an examination of the Nucleic Acids Research manner in which the enzyme is distributed in different fractions of chromatin would allow a determination of how chromatin proteins or the ordered packaging of nucleosomes affects the interaction between unmethylated sites in DNA and endogenous DNA methyltransferases.…”

Section: Introductionmentioning

confidence: 99%

Localization of DNA methyltransferase in the chromatin of Friend erythroleukemia cells

Creusot

Christman

1981

Nucl Acids Res

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Chromatin fragments released from intact Friend erythroleukemia cell nuclei during limited incubation with micrococcal nuclease, DNase II or DNase I were analyzed to determine the distribution of DNA methyltransferase in chromatin. The enzyme was released in a free form when internucleosomal DNA was digested with micrococcal nuclease but was found associated with Mg++-precipitable polynucleosomes after DNase II digestion.Less than 25% of the enzyme was released from nuclei incubated with DNase I under conditions where transcriptionally active chromatin should have been completely digested. These results indicated that the bulk of DNA methyltransferase was bound to "linker" DNA in condensed regions of chromatin. Preferential rebinding of free enzyme to linker DNA was also demonstrated in vitro. The possibility that chromatin proteins play a role in regulating access of DNA methyltransferase to specific sites in DNA is discussed in light of these findings.

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Section: Introductionmentioning

confidence: 99%

Localization of DNA methyltransferase in the chromatin of Friend erythroleukemia cells

Creusot

Christman

1981

Nucl Acids Res

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“…The high fidelity with which methylation patterns are inherited (Wigler et al, 1981;Harland, 1982;Stein et al, 1982) suggests that permanent alterations in gene expression might result if more than one cycle of DNA replication were to occur under conditions that favoured hypomethylation. It was observed previously in our laboratory (Shivapurkar & Poirier, 1983) that the administration to rats of a methyldeficient diet resulted in a decrease in AdoMet, the DNA methylase substrate (Sheid et al, 1968), and an increase in AdoHcy, a competitive inhibitor of DNA methylase (Cox et al, 1977 (50-60g) were supplied by the Frederick Cancer Research Facility Animal Production Area. Animals were distributed into four groups (five animals/group).…”

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confidence: 99%

Hypomethylation of hepatic nuclear DNA in rats fed with a carcinogenic methyl-deficient diet

Wilson¹,

Shivapurkar²,

Poirier³

1984

Biochemical Journal

152

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A progressive decrease was observed in the 5-methyldeoxycytidine content of hepatic DNA in male F344 rats fed with a hepatocarcinogenic methyl-deficient diet. The same dietary regimen resulted in altered hepatic contents of S-adenosylmethionine, the methyl-donating species, and S-adenosylhomocysteine, an inhibitor of DNA methylase. The data indicate that this carcinogenic dietary manipulation is sufficient to alter a possible regulatory process, DNA methylation.

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“…Deoxyribonucleic acid (DNA) methylation specifies genetic infornation in that specific sequences are methylated and the amount of methylation is both species and tissue specific (5,15,19,42,56,64,74,78,83,84). In nuclear DNA of multicellular eucaryotes, the amount of 5-methylcytosine (MeCyt) varies from as little as 0.17 mol% in insects (3) to as much as 50 mol% in certain plants (72).…”

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Deoxyribonucleic acid methylation and chromatin organization in Tetrahymena thermophila.

Pratt¹,

Hattman²

1981

Mol. Cell. Biol.

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Deoxyribonucleic acid (DNA) of the transcriptionally active macronucleus of Tetrahymena thermophila is methylated at the N6 position of adenine to produce methyladenine (MeAde); approximately 1 in every 125 adenine residues (0.8 mol%) is methylated. Transcriptionally inert micronuclear DNA is not methylated (s0.01 mol% MeAde; M. A. Gorovsky, S. Hattman, and G. L. Pleger, J. Cell Biol. 56:697-701, 1973). There is no detectable cytosine methylation in macronuclei in Tetrahymena DNA (s0.01 mol% 5-methylcytosine). MeAde-containing DNA sequences in macronuclei are preferentially digested by both staphylococcal nuclease and pancreatic deoxyribonuclease I. In contrast, there is no preferential release of MeAde during digestion of purified DNA. These results indicate that MeAde residues are predominantly located in "linker DNA" and perhaps have a function in transcription. Pulse-chase studies showed that labeled MeAde remains preferentially in linker DNA during subsequent rounds of DNA replication; i.e., there is little, if any, movement of nucleosomes during chromatin replication. This implies that nucleosomes may be phased with respect to DNA sequence.Deoxyribonucleic acid (DNA) methylation specifies genetic infornation in that specific sequences are methylated and the amount of methylation is both species and tissue specific (5,15,19,42,56,64,74,78,83,84). In nuclear DNA of multicellular eucaryotes, the amount of 5-methylcytosine (MeCyt) varies from as little as 0.17 mol% in insects (3) to as much as 50 mol% in certain plants (72). DNA of unicellular eucaryotes generally contains either MeCyt or methyladenine (MeAde), or both (19,31,36,54,56). Recent evidence suggests that site-specific methylation of cytosine in eucaryotes may be related to the control of transcription; e.g., transcriptionally competent genes are not methylated at sites which are methylated in cells not transcribing those genes (11,14,16,17,20,21,24,45,48,50,61,70,73,75,78

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Deoxyribonucleic acid methylase of mammalian tissues

Abstract: insoluble nuclear fraction. Cytosine is the only target base of the methylase. The enzyme is species specific and appears to have different levels of activity in different organs of the same animal. Some of the properties of the mammalian deoxyribonucleic acid methylase are described.

Cited by 83 publications

References 5 publications

Localization of DNA methyltransferase in the chromatin of Friend erythroleukemia cells

Localization of DNA methyltransferase in the chromatin of Friend erythroleukemia cells

Hypomethylation of hepatic nuclear DNA in rats fed with a carcinogenic methyl-deficient diet

Deoxyribonucleic acid methylation and chromatin organization in Tetrahymena thermophila.

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