Transformation of Tetrahymena thermophila with hypermethylated rRNA genes.
Transformation of Tetrahymena thermophila with hypermethylated rRNA genes.
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用高甲基化 rRNA 基因转化嗜热四膜虫。
DOI：
10.1128/mcb.8.4.1664-1669.1988
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发表时间：
1988
影响因子：
5.3
通讯作者：
Yao,MC
中科院分区：
文献类型：
--
作者：
Karrer,KM;Yao,MC
嗜热四膜虫的染色体外rRNA基因（rDNA）含有0.4%的n6 -甲基腺嘌呤。分离C3菌株rDNA，体外超甲基化，微注射到B菌株宿主细胞中。建立克隆细胞系，根据注射的rDNA对paromomycin的抗性选择转化子。测定了3种甲基化酶（dam、EcoRI和clai）对序列5 ‘ -NAT-3 ’的甲基化作用。与模拟甲基化对照相比，注射rDNA的高甲基化对转化效率没有影响。注射的C3菌株rDNA有效地取代宿主rDNA，成为rDNA分子群体的主要组成部分。注射DNA的高甲基化没有维持到20至25代细胞。
The extrachromosomal rRNA genes (rDNA) ofTetrahymena thermophilacontain 0.4%N6-methyladenine. C3 strain rDNA was isolated, hypermethylated in vitro, and microinjected into B strain host cells. Clonal cell lines were established, and transformants were selected on the basis of resistance to paromomycin, conferred by the injected rDNA. The effects of methylation by three enzymes which methylate the sequence 5′-NAT-3′, the dam,EcoRI, andClaI methylases, were tested. Hypermethylation of the injected rDNA had no effect on transformation efficiency relative to mock-methylated controls. The injected C3 strain rDNA efficiently replaced host rDNA as the major constituent of the population of rDNA molecules. Hypermethylation of the injected DNA was not maintained through 20 to 25 cell generations.