Re-replication of SV40 minichromosomes is inhibited at the stage of chain elongation

Abstract

The template activities of protein-free SV40 DNA and SV40 minichromosomes for DNA re-repllcatlon are compared in In vitro replication assays. Density substitution experiments and two-dimensional gel electrophoresis show that protein-free DNA can replicate for at least two cycles whereas salt-treated minichromosomes replicate only once. Re-repllcatlon of minichromosomes is blocked at the stage of replicatlve chain elongation suggesting that repll-catively assembled chromatin has structural features that prevent a second round of replication. © 1994 Oxford University Press.