Replication control of autonomously replicating human sequences.
Three autonomously replicating plasmids carrying human genomic DNA and a vector derived from Epstein-Barr virus were studied by density labelling to determine the number of times per cell cycle these plasmids replicate in human cells. Each of the plasmids replicated semi-conservatively once per cell cycle. The results suggest that these human autonomously replicating sequences undergo replication following the same controls as chromosomal DNA and represent a good model system for studying chromosomal replication. We also determined the time within the S phase of the cell cycle that three of the plasmids replicate. Centromeric alpha sequences, which normally replicate late in S phase when in their chromosomal context, were found to replicate earlier when they mediate replication on an extrachromosomal vector. Reproducible patterns of replication within S phase were found for the plasmids, suggesting that the mechanism specifying time of replication may be subject to experimental analysis with this system.
Haase
S B
SB
Department of Genetics, Stanford University School of Medicine, CA 94305.
Calos
M P
MP
D001973:Bromodeoxyuridine; D002460:Cell Line; D002499:Centrifugation, Density Gradient; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D004261:DNA Replication; D005822:Genetic Vectors; D004854:Herpesvirus 4, Human / Q000235:genetics; D006801:Humans; D010957:Plasmids; D012091:Repetitive Sequences, Nucleic Acid; D016196:S Phase; D014162:Transfection
D004247:DNA; D001973:Bromodeoxyuridine