Vongs A, Kakutani T, Martienssen R A, Richards E J
Cold Spring Harbor Laboratory, NY 11724.
Science. 1993 Jun 25;260(5116):1926-8. doi: 10.1126/science.8316832.
Three DNA hypomethylation mutants of the flowering plant Arabidopsis thaliana were isolated by screening mutagenized populations for plants containing centromeric repetitive DNA arrays susceptible to digestion by a restriction endonuclease that was sensitive to methylated cytosines. The mutations are recessive, and at least two are alleles of a single locus, designated DDM1 (for decrease in DNA methylation). Amounts of 5-methylcytosine were reduced over 70 percent in ddm1 mutants. Despite this reduction in DNA methylation levels, ddm1 mutants developed normally and exhibited no striking morphological phenotypes. However, the ddm1 mutations are associated with a segregation distortion phenotype. The ddm1 mutations were used to demonstrate that de novo DNA methylation in vivo is slow.
通过筛选诱变群体中含有对甲基化胞嘧啶敏感的限制性内切酶可消化的着丝粒重复DNA阵列的植物，分离出了开花植物拟南芥的三个DNA低甲基化突变体。这些突变是隐性的，并且至少有两个是单个基因座的等位基因，命名为DDM1（DNA甲基化减少之意）。在ddm1突变体中，5-甲基胞嘧啶的含量减少了70%以上。尽管DNA甲基化水平有所降低，但ddm1突变体正常发育，没有表现出明显的形态学表型。然而，ddm1突变与分离畸变表型相关。ddm1突变被用于证明体内从头DNA甲基化是缓慢的。
