文章基本信息

标题：Induction of Nucleolar and Mitochondrial DNA Replication in Tetrahymena pyriformis
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作者：Jan Engberg ; Jytte R. Nilsson ; Ronald E. Pearlman 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1974
卷号：71
期号：3
页码：894-898
DOI：10.1073/pnas.71.3.894
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Selective induction of replication of nucleolar and mitochondrial DNA has been demonstrated in starved-refed cultures of Tetrahymena pyriformis by different techniques. Labeling of starved cells with [3H]thymidine during a nutritional shift-up and analysis of the DNA in isopycnic CsCl gradients shows that the two initially labeled species of DNA are two species banding on the heavy and light side of the bulk macronuclear DNA. In isolated macronuclei the radioactivity is found only in the high density fraction, which has been shown to be of nucleolar origin. In sucrose gradients the newly replicated mitochondrial and nucleolar DNAs sediment considerably slower than the bulk DNA, as one discrete band corresponding to a molecular weight of about 3 to 4 x 107. Electron microscope autoradiography of cells labeled with [3H]thymidine as above shows that the peripheral nucleoli of the macronucleus as well as the mitochondria are labeled before any radioactivity is found in the chromatin granules of the macronucleus. The results clearly indicate that nucleolar and mitochondrial DNA replication are under a control independent of that for the replication of bulk DNA.
关键词：nutritional shift-up ; CsCl gradients ; EM-autoradiography ; sucrose gradients