STIMULATION OF DNA REPLICATION BY TRUNCATED FOS AND JUN PROTEINS IN A CELL-FREE EXTRACT OF XENOPUS EGGS

Abstract The effects of truncated Fos (residue 116-211) and/or Jun (residue 224-334) proteins on the DNA replication of plasmid with or without an AP-1 binding site were examined in a cell-free extract of Xenopus eggs. These truncated proteins, which are depleted of the domains necessary for transcriptional activation, stimulated semiconservative DNA replication only in combination and in the presence of plasmid with an AP-1 binding site. These results suggest that truncated Fos and Jun proteins act together to stimulate DNA replication and that activation depends on the presence of an AP-1 binding site in the Xenopus cell-free DNA replication system.