Function of yeast Rad52 protein as a mediator between replication protein A and the Rad51 recombinase.
The RAD51 and RAD52 genes of Saccharomyces cerevisiae are key members of the RAD52 epistasis group required for genetic recombination and the repair of DNA double-stranded breaks. The RAD51 encoded product mediates the DNA strand exchange reaction. Efficient strand exchange is contingent upon the addition of the heterotrimeric single-stranded DNA binding factor replication protein A (RPA) after Rad51 has nucleated onto the single-stranded DNA. However, if the single-stranded DNA is incubated with Rad51 and RPA simultaneously to mimic what may be expected to occur in vivo, the efficiency of strand exchange decreases dramatically, revealing an inhibitory effect of RPA that is distinct from its stimulatory function. Interestingly, the inclusion of Rad52 protein, which has been purified in this study from yeast cells, restores the efficiency of strand exchange. Thus, Rad52 functions as a co-factor for the Rad51 recombinase, acting specifically to overcome the apparent competition by RPA for binding to single-stranded DNA.
Sung
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Department of Molecular Medicine and the Institute of Biotechnology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78245-3207, USA. sung@uthscsa.edu
D004265:DNA Helicases / Q000378:metabolism; D004261:DNA Replication; D004271:DNA, Fungal / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism* / Q000502:physiology*; D005656:Fungal Proteins / Q000302:isolation & purification / Q000378:metabolism* / Q000502:physiology*; D051135:Rad51 Recombinase; D051721:Rad52 DNA Repair and Recombination Protein; D011995:Recombination, Genetic; D051716:Replication Protein A; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins
D004271:DNA, Fungal; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C497197:RAD52 protein, S cerevisiae; D051721:Rad52 DNA Repair and Recombination Protein; D051716:Replication Protein A; D029701:Saccharomyces cerevisiae Proteins; C495151:RAD51 protein, S cerevisiae; D051135:Rad51 Recombinase; D004265:DNA Helicases