ABERRANT DOUBLE REPLICATION OF SEGMENTS OF CHROMOSOMAL DNA FOLLOWING DNA-SYNTHESIS INHIBITION BY CYTOSINE-ARABINOSIDE

Using two different cell lines growing logarithmically, it is demonstrated that inhibition of DNA synthesis by cytosine arabinoside leads to a disruption of the sequence of replication of the chromosomal DNA. After release of the inhibition, some DNA synthesis is reinitiated in DNA segments replicated earlier in that S phase, leading to double replication of some DNA segments. This was directly demonstrated by showing that, following removal of the inhibitor, DNA was synthesized off template strands which had themselves been synthesized only 1-2 h before the addition of the inhibitor. © 1979.