DNA replication in tetrahymena after release from thymidine starvation
نویسندگان
چکیده
منابع مشابه
33 DNA Replication in Tetrahymena
The linear ribosomal RNA gene (rDNA) minichromosome in the somatic macronucleus of Tetrahymena thermophila serves as a paradigm for multiple mechanisms of regulation of chromosomal DNA replication. Whereas chromosomal DNA replication in most eukaryotes is under strict cell cycle control, additional mechanisms appear to be involved in the regulation of rDNA replication in vegetatively growing Te...
متن کاملThymidine Triphosphate Synthesis in Tetrahymena
The amount of thymidine-H(3) converted to thymidine-H(3) monophosphate in 30 min formed the basis for assays of thymidine kinase in cell extracts from Tetrahymena pyriformis. The optimal concentration of adenosine triphosphate is lower than that required by other cell types. Thymidine triphosphate does not exercise any feedback control of the enzyme. Other deoxyprimidine nucleotides were tested...
متن کاملReplication of macronuclear DNA in the cytoplasm of Tetrahymena pyriformis.
Previous experiments showed that a synchronous population of Tetrahymena could divide even though DNA replication was blocked during the latter half of the preceding S-period byaddition of methotrexate plus uridine (M + U). Furthermore, it was found that the DNA fraction which was in replication at the time of inhibition became localized in the cytoplasm following elimination from the nucleus a...
متن کاملCheckpoint Activation of an Unconventional DNA Replication Program in Tetrahymena
The intra-S phase checkpoint kinase of metazoa and yeast, ATR/MEC1, protects chromosomes from DNA damage and replication stress by phosphorylating subunits of the replicative helicase, MCM2-7. Here we describe an unprecedented ATR-dependent pathway in Tetrahymena thermophila in which the essential pre-replicative complex proteins, Orc1p, Orc2p and Mcm6p are degraded in hydroxyurea-treated S pha...
متن کاملH3-thymidine Derivative Pools in Relation to Macronuclear Dna Synthesis in Tetrahymena Pyriformis
The formation of a soluble H(3)-thymidine derivative pool has been examined in Tetrahymena pyriformis as a function of macronuclear DNA synthesis during the cell life cycle. An autoradiographic technique which allows the detection of water-soluble materials within a cell has shown that these cells do not take up and retain exogenous H(3)-thymidine during G1 or G2. Uptake of H(3)-thymidine is re...
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ژورنال
عنوان ژورنال: Carlsberg Research Communications
سال: 1977
ISSN: 0105-1938
DOI: 10.1007/bf02910460