Yeast DNA Replication

Our understanding of the molecular events involved in DNA replication in bacteria is largely due to the development of in vitro DNA replication systems that have allowed the identification and characterization of many of the proteins and DNA sequences required. Since the same gene products used in vivo are also required in such in vitro systems, conditional lethal mutants deficient in DNA replication are also defective in in vitro synthesis. Restoration of in vitro synthesis by the addition of wild-type gene product provides a biochemical complementation assay for the protein encoded by the mutant gene. This combined genetic and biochemical approach has resulted in the purification and characterization of numerous proteins required for accurate replication. A second important aspect of the bacterial studies has been the use of model DNA templates, many constructed by recombinant DNA techniques, in both in vitro and in vivo replication systems for defining the specific DNA sequences that are important for initiation, termination and regulation of DNA synthesis. However, in spite of the progress in prokaryotes, little is known about the mechanisms of eukaryotic DNA replication.