Recombinant Candida glabrata DNA repair protein RAD59 (RAD59)

Introduction to Recombinant Candida Glabrata DNA Repair Protein RAD59 (RAD59)

The Recombinant Candida glabrata DNA repair protein RAD59 (RAD59) is a protein involved in DNA repair, specifically in the homologous recombination pathway . Homologous recombination (HR) is a crucial mechanism for repairing DNA double-strand breaks (DSBs) and maintaining genomic stability . RAD59 is part of the RAD52 epistasis group, which includes proteins like Rad51, Rad52, Rad54, and Rad55/57 .

Role in DNA Repair and Recombination

RAD59 participates in the repair of double-strand breaks in DNA during vegetative growth through recombination and single-strand annealing . It functions in a RAD51-independent recombination pathway, suggesting it has a distinct role in DNA repair .

RAD59 in Candida albicans

In Candida albicans, the pathogenic fungus, the role of RAD59 has been characterized alongside other homologous recombination genes like RAD51 and RAD52 . Studies show that disrupting RAD59 in Candida albicans results in a UV-sensitive phenotype, indicating its involvement in repairing UV-induced DNA damage .

Interaction with RAD52

RAD59 interacts physically with RAD52, a protein essential for homology-dependent repair of DNA double-strand breaks . This interaction suggests that RAD59 and RAD52 function together in the same recombination pathway, either as a complex or through overlapping functions .

Functional Studies and Phenotypes

Genetic studies in Saccharomyces cerevisiae have shown that the rad59 mutation causes a moderate sensitivity to ionizing radiation . This defect can be suppressed by over-expression of RAD52, but not the other way around, further highlighting the interaction and functional relationship between RAD59 and RAD52 .

Comparison with Other HR Proteins

In Candida albicans, depletion of RAD51 or RAD52 causes a dramatic drop in the number of survivors after exposure to γ-ionizing radiation, whereas depletion of RAD59 causes a moderate decrease . This indicates that RAD51 and RAD52 play more significant roles in repairing DNA damage from ionizing radiation compared to RAD59 .

RAD59 Structure and Homology

The Rad59 protein is approximately half the length of Rad52 proteins and shows homology to the conserved amino terminal region of this family . This structural relationship supports the functional interaction between RAD59 and RAD52 in DNA repair processes .

RAD59 Activity In Vitro

Purified RAD59 can efficiently anneal complementary oligonucleotides and overcome the inhibition of annealing imposed by replication protein A (RPA) . While RAD59 has strand-annealing activity in vitro, this activity alone is insufficient to promote strand annealing in vivo in the absence of RAD52 .

Role in Genome Stability

Homologous recombination factors like RAD59 contribute to genome stability under non-damaging conditions . These proteins are essential for maintaining proper cell growth and DNA integrity .