Constancy of adenine methylation in Tetrahymena macronuclear DNA.
Constancy of adenine methylation in Tetrahymena macronuclear DNA.
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四膜虫大核 DNA 中腺嘌呤甲基化的恒定性。
DOI：
10.1111/j.1550-7408.1990.tb01165.x
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Stein-Gavens,S
中科院分区：
文献类型：
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作者：
Karrer,KM;Stein-Gavens,S
为了确定腺嘌呤甲基化的模式是否随着附近基因的转录活性而改变，我们对四膜虫的大核DNA进行了检测。将来自生长、饥饿和接合细胞的DNA用六种限制性内切酶消化，所述限制性内切酶对其识别位点内的腺嘌呤甲基化敏感。限制性DNA的Southern印迹用与polyA+ RNA同源的7个cDNA克隆和1个基因组克隆探测，其转录活性随细胞的生理状态而变化。其中一个cDNA克隆BC11以前没有被描述过。它与一个1.3kb的转录本杂交，该转录本存在于饥饿和接合的细胞群体中，但不存在于生长的细胞中。在基因组DNA的Southern印迹上，它与在密切相关的菌株的DNA之间高度多态的复杂的条带模式杂交。估计在137和272个位点之间检测了甲基化的变化，包括至少27个已知被甲基化的位点。在不同生理状态的细胞中，没有观察到限制性片段的大小差异。这些数据表明，甲基化模式，这是在大核发育过程中确定的，不随细胞的生理状态而变化。
Macronuclear DNA fromTetrahymenawas examined in order to determine whether the pattern of adenine methylation changed with the transcriptional activity of nearby genes. The DNA from growing, starved and conjugating cells was digested with six restriction enzymes which are sensitive to methylation of adenine within their recognition site. Southern blots of the restricted DNAs were probed with seven cDNA clones and one genomic clone which are homologous to polyA+RNAs, whose transcriptional activity varies with the physiological state of the cell. One of the cDNA clones, BC11, had not been described previously. It hybridized to a 1.3kb transcript which was present in populations of starved and conjugating, but not in growing cells. On Southern blots of genomic DNA it hybridized to a complex pattern of bands which was highly polymorphic between the DNAs of closely related strains.It was estimated that between 137 and 272 sites were assayed for changes in methylation, including at least 27 sites which were known to be methylated. No differences were seen in the size of restriction fragments from cells in different physiological states. The data suggested that the methylation pattern, which is determined during macronuclear development, does not vary with the physiological state of the cell.