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The Primary DNA Sequence Determines in Vitro Methylation by Mammalian DNA Methyltransferases

1986; Academic Press; Linguagem: Inglês

10.1016/s0079-6603(08)60025-2

2211-9108

Arthur H. Bolden, Cheryl A. Ward, Carlo M. Nalin, Arthur Weissbach,

RNA modifications and cancer

This chapter discusses the mechanism by which mammalian DNA methyltransferases recognize and modify DNA. The studies described in the chapter used DNA methyltransferases that were purified 800-fold from the nuclear extracts of HeLa S3 cells and 115- fold from the extracts of the mouse erythroleukemia (MEL) cell nuclei. The strategy of the purification procedure was designed to produce DNA niethyltransferase preparations virtually free of deoxyribonuclease activity. Correlations between the level of DNA methylation of specific genomic sequences and the expression of certain genes in differentiating tissues suggest that DNA methylation is one of the possible mechanisms for the control of gene expression. If DNA methylation is a primary event in the regulation of gene expression, the elucidation of the complex factor(s) that may play important role(s) in DNA methylation would facilitate an understanding of the regulation of gene expression. The use of defined oligodeoxynucleotides and synthetic polydeoxyribonucleotides as substrates for the enzyme has facilitated the identification of various factors that influence the rate and specificity of DNA methylation in vitro.