Dss1 release activates DNA binding potential in Brh2.

TitleDss1 release activates DNA binding potential in Brh2.
Publication TypeJournal Article
Year of Publication2012
AuthorsZhou Q, Kojic M, Holloman WK
Date Published2012 Nov 13
KeywordsDNA Repair, DNA-Binding Proteins, Fungal Proteins, Protein Binding, Ustilago

Dss1 is an intrinsically unstructured polypeptide that partners with the much larger Brh2 protein, the BRCA2 ortholog in Ustilago maydis, to form a tight complex. Mutants lacking Dss1 have essentially the same phenotype as mutants defective in Brh2, implying that through physical interaction Dss1 serves as a positive activator of Brh2. Dss1 associates with Brh2 through an interaction surface in the carboxy-terminal region. Certain derivatives of Brh2 lacking this interaction surface remain highly competent in DNA repair as long as a DNA-binding domain is present. However, the Dss1-independent activity raises the question of what function might be met in the native protein by having Brh2 under Dss1 control. Using a set of Brh2 fusions and truncated derivatives, we show here that Dss1 is capable of exerting control when there is a cognate Dss1-interacting surface present. We find that association of Dss1 attenuates the DNA binding potential of Brh2 and that the amino-terminal domain of Brh2 helps evict Dss1 from its carboxy-terminal interaction surface. The findings presented here add to the notion that Dss1 serves in a regulatory capacity to dictate order in association of Brh2's amino-terminal and carboxy-terminal domains with DNA.

Alternate JournalBiochemistry
PubMed ID23094644
PubMed Central IDPMC3617921
Grant ListGM42482 / GM / NIGMS NIH HHS / United States
GM79859 / GM / NIGMS NIH HHS / United States
R01 GM042482 / GM / NIGMS NIH HHS / United States
R01 GM079859 / GM / NIGMS NIH HHS / United States

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