of Work: DNA damage produces cell death or mutation, both of which can have serious health consequences. Most DNA damage is repaired before it can cause harm. The classically defined mechanisms of DNA repair are direct reversal of the damage, excision of the damage followed by resynthesis of the damaged strand, recombinational processes that bypass the damage without removing it, and mutagenic translesion synthesis. A fourth but poorly characterized mechanism was identified in bacteriophage T4. Mutations in certain genes of DNA replication reduce survival after treatments inducing a variety of kinds of DNA damage, but the mutations hardly affect phage reproduction. The process does not involve any of the classical mechanisms and was named """"""""replication repair"""""""" because it involves enzymes of DNA replication. We have set up the Alberts-Nossal bacteriophage T4 eight-protein system for replicating both strands of DNA in vitro and have investigated the processing of damaged DNA comparing wild-type and mutant enzymes. A mutant DNA-binding protein exhibits reduced affinity for single-stranded DNA. Using an artificial replication fork, we can observe template switching in which a blocked leading strand can switch to the other daughter strand in order to continue synthesis beyond the block. In this assay, the mutant proteins are strongly defective in promoting strand switching.
| Schultz Jr, Gary E; Drake, John W (2008) Templated mutagenesis in bacteriophage T4 involving imperfect direct or indirect sequence repeats. Genetics 178:661-73 |
| Schultz Jr, Gary E; Carver, Geraldine T; Drake, John W (2006) A role for replication repair in the genesis of templated mutations. J Mol Biol 358:963-73 |
| Kadyrov, Farid A; Drake, John W (2004) UvsX recombinase and Dda helicase rescue stalled bacteriophage T4 DNA replication forks in vitro. J Biol Chem 279:35735-40 |
| Kadyrov, Farid A; Drake, John W (2003) Properties of bacteriophage T4 proteins deficient in replication repair. J Biol Chem 278:25247-55 |
| Kadyrov, Farid A; Drake, John W (2002) Characterization of DNA synthesis catalyzed by bacteriophage T4 replication complexes reconstituted on synthetic circular substrates. Nucleic Acids Res 30:4387-97 |
| Kadyrov, F A; Drake, J W (2001) Conditional coupling of leading-strand and lagging-strand DNA synthesis at bacteriophage T4 replication forks. J Biol Chem 276:29559-66 |
