The mechanism of coordination between DNA replication and cell division was studied in Tetrahymena pyriformis GL-C by manipulation of the timing of these events with heat shocks and inhibition of DNA synthesis. Preliminary experiments showed that the inhibitor combination methotrexate and uridine (M + U) was an effective inhibitor of DNA synthesis. Inhibition of the progression of DNA synthesis with M + U in exponentially growing cells, in which one S period usually occurs between two successive divisions, or in heat-shocked cells, when successive S periods are known to occur between divisions, resulted in the complete suppression of the following division. In further experiments in which the division activities were reassociated with the DNA synthetic cycle by premature termination of the heat-shock treatment, it was shown that (a) the completion of one S period during the treatment was sufficient for cell division, (b) the beginning of division events suppressed the initiation of further S periods, and (c) if further S periods were initiated while the heat-shock treatment was continued, division preparations could not begin until the necessary portion of the S period was completed, even though DNA had previously been duplicated. It was concluded that a temporal incompatibility exists between DNA synthesis and division which may reflect a coupling mechanism which insures their coordination during the normal cell cycle.
Article| June 01 1972
EVIDENCE FOR A TEMPORAL INCOMPATIBILITY BETWEEN DNA REPLICATION AND DIVISION DURING THE CELL CYCLE OF TETRAHYMENA
William R. Jeffery
From the Department of Zoology, University of Iowa, Iowa City, Iowa 52240.
Dr. Jeffery's present address is McArdle Laboratory for Cancer Research, Medical Center, The University of Wisconsin, Madison, Wisconsin 53706.
Received: November 17 1971
Revision Received: January 31 1972
Online Issn: 1540-8140
Print Issn: 0021-9525
Copyright © 1972 by The Rockefeller University Press
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William R. Jeffery; EVIDENCE FOR A TEMPORAL INCOMPATIBILITY BETWEEN DNA REPLICATION AND DIVISION DURING THE CELL CYCLE OF TETRAHYMENA . J Cell Biol 1 June 1972; 53 (3): 624–634. doi: https://doi.org/10.1083/jcb.53.3.624
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