Analysis of Rad51 in the Social Amoeba Dictyostelium Discoideum: Sequence, Induction and Disruption

Abstract

The cellular slime mold Dictyostelium discoideum, a lower eukaryote feeding on bacteria in soil, is highly resistant to DNA damaging agents. D. discoideum expresses at least two RecA homologs, Rad51 and mitochondria localizing RecA. Rad51 consisting of 351 amino acid residues is 69% identical to human Rad51. UV light-irradiation and H2O2-treatment increased the expression level of Rad51, suggesting that Rad51 is required for DNA repair in D. discoideum. A gene disruption mutant was not viable, suggesting that Rad51 is essential for D. discoideum.

Xpf and Not the Fanconi Anaemia Proteins or Rev3 Accounts for the Extreme Resistance to Cisplatin in Dictyostelium discoideum

“…One obvious pathway would be HR. However, to date we and others have not been able to knockout core genes in this pathway [35] , [36] . Perhaps this could be due to an essential role for HR in cell viability.…”

“…The undamaged copy could then be used as the template for HR-mediated double strand break repair ( Figure 7 ). Such a model predicts the requirement for HR genes in crosslink repair, a proposition that is currently difficult to address, since we and others thus far been unable to disrupt HR genes in Dictyostelium [35] , [36] . In addition, this model of crosslink repair may require additional nucleases to not only to create but also to process DNA double strand breaks, remove flaps or resolve secondary structures.…”