Transformation of tetrahymena thermophila with hypermethylated rRNA genes
The extrachromosomal rRNA genes (rDNA) of Tetrahymena thermophila contain 0.4% N/sup 6/-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, and ClaI 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.
- Research Organization:
- Dept. of Biology, Brandeis Univ., Waltham, MA (US)
- OSTI ID:
- 7143997
- Journal Information:
- Mol. Cell. Biol.; (United States), Vol. 8:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
RIBOSOMAL RNA
GENES
TETRAHYMENA
GENETIC ENGINEERING
MUTANTS
CLONE CELLS
DRUGS
ENZYME ACTIVITY
IN VITRO
METHYLATION
SENSITIVITY
ANIMALS
CELL CULTURES
CHEMICAL REACTIONS
CILIATA
INVERTEBRATES
MICROORGANISMS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PROTOZOA
RNA
550200* - Biochemistry
550400 - Genetics