Open AccessRibosome Biosynthesis Is not Necessary for Initiation of DNA Replication
Author(s) -
GRUMMT Friedrich,
GRUMMT Ingrid,
MAYER Evelyne
Publication year - 1979
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1979.tb13083.x
Subject(s) - baby hamster kidney cell , ribosome , ribosomal rna , cytoplasm , microbiology and biotechnology , biology , dna synthesis , cell culture , cell cycle , rna , cell division , messenger rna , dna replication , cell , dna , biochemistry , genetics , gene
Synthesis of mature 28‐S ribosomal RNA and 60‐S ribosomal subunits is inhibited in baby hamster kidney (BHK) cell line ts 422E at non‐permissive temperature (39°C). This leads to a 66% decrease of total ribosomes per cell, a marked imbalance between the large and small ribosomal subunits in the cytoplasm and a decrease of cells per dish after prolonged culture at 39°C. However, inhibition of ribosome synthesis does not affect progression of cells through the G 1 period of the cell division cycle, the length of the pre‐replicative period, and the rate of entry of cells into S phase. In contrast to culture at non‐permissive temperature, culture of BHK ts 422E cells in the presence of 0.04 μg/ml actinomycin D at 33°C inhibits markedly the entry into S period. It is concluded that low doses of actinomycin D exert their inhibitory effect on cell growth by preventing maturation and transport of mRNA rather than by interfering with ribosome synthesis. Microfluorometric analysis revealed only slight differences in the distribution of BHK ts 422E cells in G 1 , S and G 2 phases of the cycle either when cultured at 33°C or at 39°C. When too few ribosomes per cell are produced in BHK ts 422E cells at 39°C, cells do not seem to be arrested reversibly at a specific point of the cell cycle but rather to die at random.