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DNA SYNTHESIS AND MITOSIS IN MERISTEMS: REQUIREMENTS FOR RNA AND PROTEIN SYNTHESIS
Author(s) -
Webster P. L.,
Hof J. Van't
Publication year - 1970
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1970.tb09798.x
Subject(s) - cycloheximide , biology , puromycin , mitosis , meristem , protein biosynthesis , rna , dna synthesis , cell cycle , dactinomycin , microbiology and biotechnology , dna , biochemistry , cell , gene
Following provision of sucrose to starved, stationary phase pea root meristems, G 1 and G 2 cells enter DNA synthesis and mitosis, respectively. Puromycin (450 μg/ml) and cycloheximide (5 μg/ml) completely prevent this initiation of progression through the cell cycle. Actinomycin D (10 μg/ml) has no effect on the initial entry of G 1 and G 2 cells into S and mitosis, although later entry is prevented. The resistance of the cells to actinomycin D is lost slowly with time in medium without sucrose, suggesting that an RNA required for the resumption of proliferative activity is being gradually lost. The effects of the inhibitors on transitional and proliferative phase meristem cells indicate that such dividing cells do indeed have sufficient of the requisite RNA for 8‐12 hr progression through the cycle, but that protein synthesis is required continuously. It is suggested that this RNA is the one lost slowly during starvation, allowing starved cells to reinitiate progression through the cycle in the presence of actinomycin D.