RecQ Helicase - Mechanism

Mechanism

The proper function of RecQ helicases requires the specific interaction with topoisomerase III (Top 3). Top 3 changes the topological status of DNA by binding and cleaving single stranded DNA and passing either a single stranded or a double stranded DNA segment through the transient break and finally religating the break. The interaction of RecQ helicase with topoisomerase III at the N-terminal region is involved in the suppression of spontaneous and damage induced recombination and the absence of this interaction results in a lethal or very severe phenotype. The emerging picture clearly is that RecQ helicases in concert with Top 3 are involved in maintaining genomic stability and integrity by controlling recombination events, and repairing DNA damage in the G2-phase of the cell cycle. The importance of RecQ for genomic integrity is exemplified by the diseases that arise as a consequence of mutations or malfunctions in RecQ helicases; thus it is crucial that RecQ is present and functional to ensure proper human growth and development.