title: The supply of exogenous deoxyribonucleotides accelerates the speed of the replication fork in early S-phase.
abstract: Earlier studies have established that the average speed of a replication fork is two to three times slower in early S-phase than in late S-phase and that the intracellular 2'-deoxyribonucleoside 5'-triphosphate pools grow during S-phase. In this study, the effect of the exogenous 2'-deoxyribonucleoside 5'-triphosphate (dNTP) supply on the average replication speed in a synchronised population of human HeLa cells was tested. The speed of replication fork movement was measured on extended DNA fibers labelled with 2'-deoxythymidine analogues 5-chloro-2'-deoxyuridine and 5-iodo-2'-deoxyuridine. We show that the introduction of exogenous dNTPs accelerates the replication process at the beginning of DNA synthesis only. In late S-phase, the administration of additional dNTPs has no effect on the speed of replication forks. The availability of 2'-deoxynucleotides seems to be a rate-limiting factor for DNA replication during early S-phase.
authors.affiliation: Department of Cell Biology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Albertov 4, 128 00 Prague 2, Czech Republic.
authors.forename: J
authors.initials: J
authors.lastname: Malínsky
authors.forename: K
authors.initials: K
authors.lastname: Koberna
authors.forename: D
authors.initials: D
authors.lastname: Stanĕk
authors.forename: M
authors.initials: M
authors.lastname: Masata
authors.forename: I
authors.initials: I
authors.lastname: Votruba
authors.forename: I
authors.initials: I
authors.lastname: Raska
mesh_terms: D004261:DNA Replication / Q000187:drug effects*; D003854:Deoxyribonucleotides / Q000494:pharmacology*; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D008856:Microscopy, Fluorescence; D016196:S Phase / Q000187:drug effects*
chemical_list: D003854:Deoxyribonucleotides