[Replication of chromosomal DNA in Chinese hamster cells, cultivated at different temperatures]

DNA fiber autoradiography was used to measure the rate of replication and the size of replication units in Chinese hamster cells cultured at 34, 37 and 39 degrees C. The average rate of DNA replication per single fork is 0.6 mcm/min at 34 degrees and 0.8 mcm/min at 37 and 39 degrees. In contrast to the change in the rate of DNA replication, no change was found in the size of replication units, which are more than 200 mcm at 31, 37 and 39 degrees. The change of the length of the S phase at various temperatures is determined only by the rate of DNA replication.