Ectopic hypermethylation of flower-specific genes in Arabidopsis
Ectopic hypermethylation of flower-specific genes in Arabidopsis
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DOI：
10.1016/s0960-9822(00)00324-9
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发表时间：
2000-02-24
期刊：
影响因子：
9.2
通讯作者：
Meyerowitz, EM
中科院分区：
文献类型：
--
作者：
Jacobsen, SE;Sakai, H;Meyerowitz, EM
背景资料：引起全基因组低甲基化的拟南芥突变是可行的，但显示出一些特定的发育异常，包括一些类似于已知的花同源异型突变。我们以前表明，在反义甲基转移酶（METI）转基因系中存在的发育异常之一，导致从异位超甲基化的SUPERMAN gene.Results：在这里，我们调查超甲基化的SUPERMAN发生在几个低甲基化突变体的程度，并描述在第二个基因，AGAMOUS的甲基化效应。SUPERMAN基因高甲基化在几个突变体中发生频率很高，导致基因组DNA甲基化的整体下降。超甲基化模式在不同的突变体背景中基本相似。遗传分析表明，超甲基化最有可能出现在减数分裂或体细胞在植物的小部门。第二个花发育基因，AGAMOUS，也成为hypermethylated和沉默的拟南芥反义METI line.Conclusions：这些结果表明，异位甲基化的特定基因的突变背景，显示整体甲基化的下降可能是一个普遍的现象，可以解释许多发育缺陷中看到的拟南芥甲基化突变体。这类似于在癌细胞中观察到的现象，其可以同时显示特定基因的全基因组低甲基化和高甲基化。比较SUPERMAN和AGAMOUS中的甲基化序列表明，超甲基化可能涉及富含嘧啶序列形成的DNA二级结构。
Background: Arabidopsis mutations causing genome-wide hypomethylation are viable but display a number of specific developmental abnormalities, including some that resemble known floral homeotic mutations. We previously showed that one of the developmental abnormalities present in an antisense-METHYLTRANSFERASEI (METI) transgenic line resulted from ectopic hypermethylation of the SUPERMAN gene.Results: Here, we investigate the extent to which hypermethylation of SUPERMAN occurs in several hypomethylation mutants, and describe methylation effects at a second gene, AGAMOUS. SUPERMAN gene hypermethylation occurred at a high frequency in several mutants that cause overall decreases in genomic DNA methylation. The hypermethylation pattern was largely similar in the different mutant backgrounds. Genetic analysis suggests that hypermethylation most likely arose either during meiosis or somatically in small sectors of the plant. A second floral development gene, AGAMOUS, also became hypermethylated and silenced in an Arabidopsis antisense-METI line.Conclusions: These results suggest that ectopic hypermethylation of specific genes in mutant backgrounds that show overall decreases in methylation may be a widespread phenomenon that could explain many of the developmental defects seen in Arabidopsis methylation mutants. This resembles a phenomenon seen in cancer cells, which can simultaneously show genome-wide hypomethylation and hypermethylation of specific genes. Comparison of the methylated sequences in SUPERMAN and AGAMOUS suggests that hypermethylation could involve DNA secondary structures formed by pyrimidine-rich sequences.