The supply of exogenous deoxyribonucleotides accelerates the speed of the replication fork in early S-phase

• Published in: Journal of cell science Vol. 114; no. Pt 4; pp. 747 - 750
• Main Authors: Malínsky, J, Koberna, K, Stanĕk, D, Masata, M, Votruba, I, Raska, I
• Format: Journal Article
• Language: English
• Published: England 01.02.2001
• Subjects: 5-chloro-2'-deoxyuridine; 5-iodo-2'-deoxyuridine; deoxyribonucleotides; Deoxyribonucleotides - pharmacology; DNA Replication - drug effects; HeLa Cells; Humans; Kinetics; Microscopy, Fluorescence; S Phase - drug effects
• ISSN: 0021-9533; 1477-9137
• DOI: 10.1242/jcs.114.4.747

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.