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Methylation of Lilium DNA during the meiotic cycle

1971; Elsevier BV; Volume: 238; Issue: 1 Linguagem: Inglês

10.1016/0005-2787(71)90008-6

1879-3002

Yasuo Hotta, Norman Hechi,

Plant Reproductive Biology

Approx. 4.5 % of the bases in Lilium DNA are 5-methylcytosine. Methylation occurs during each of the three intervals of DNA synthesis associated with the meiotic cycle. Inhibition of methylation by ethionine or norleucine does not block DNA synthesis and does not prevent the cells from progressing through meiosis. Cells with reduced levels of methylated DNA undergo rapid DNA methylation when inhibitory condition is removed. The methylation can occur at any stage of meiosis except during those stages when the chromosomes are maximally contracted. Under normal conditions, methylation of cytosine residues occurs within 2 min of the incorporation of deoxycytidylate into DNA. Such methylation, however, does not occur until after completion of nascent DNA chains. The results provide evidence that meiotic plant cells behave in much the same way as mammalian somatic cells with respect to DNA methylation. They also indicate that reduced levels of methylation in the DNA do not interfere significantly with either chromosome pairing or chiasma formation during meiosis.