BLM and RMI1 alleviate RPA inhibition of topoIIIα decatenase activity

Yang, Jay and Bachrati, Csanad Z. and Hickson, Ian D. and Brown, Grant W. (2012) BLM and RMI1 alleviate RPA inhibition of topoIIIα decatenase activity. PLOS one, 7 (7). e41208. ISSN 1932-6203

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BLM and RMI1 alleviate RPA inhibition of topoIIIα decatenase activity
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Official URL: http://dx.doi.org/10.1371/journal.pone.0041208

Abstract

RPA is a single-stranded DNA binding protein that physically associates with the BLM complex. RPA stimulates BLM helicase activity as well as the double Holliday junction dissolution activity of the BLM-topoisomerase IIIα complex. We investigated the effect of RPA on the ssDNA decatenase activity of topoisomerase IIIα. We found that RPA and other ssDNA binding proteins inhibit decatenation by topoisomerase IIIα. Complex formation between BLM, TopoIIIα, and RMI1 ablates inhibition of decatenation by ssDNA binding proteins. Together, these data indicate that inhibition by RPA does not involve species-specific interactions between RPA and BLM-TopoIIIα-RMI1, which contrasts with RPA modulation of double Holliday junction dissolution. We propose that topoisomerase IIIα and RPA compete to bind to single-stranded regions of catenanes. Interactions with BLM and RMI1 enhance toposiomerase IIIα activity, promoting decatenation in the presence of RPA.

Item Type:Article
Additional Information:RPA is a single-stranded DNA binding protein that physically associates with the BLM complex. RPA stimulates BLM helicase activity as well as the double Holliday junction dissolution activity of the BLM-topoisomerase IIIα complex. We investigated the effect of RPA on the ssDNA decatenase activity of topoisomerase IIIα. We found that RPA and other ssDNA binding proteins inhibit decatenation by topoisomerase IIIα. Complex formation between BLM, TopoIIIα, and RMI1 ablates inhibition of decatenation by ssDNA binding proteins. Together, these data indicate that inhibition by RPA does not involve species-specific interactions between RPA and BLM-TopoIIIα-RMI1, which contrasts with RPA modulation of double Holliday junction dissolution. We propose that topoisomerase IIIα and RPA compete to bind to single-stranded regions of catenanes. Interactions with BLM and RMI1 enhance toposiomerase IIIα activity, promoting decatenation in the presence of RPA.
Keywords:topoisomerase, helicase, decatenation, TOP3A, BLM, RMI1, RPA
Subjects:C Biological Sciences > C700 Molecular Biology, Biophysics and Biochemistry
Divisions:College of Science > School of Life Sciences
ID Code:6119
Deposited By: Csanad Bachrati
Deposited On:07 Sep 2012 14:22
Last Modified:07 Sep 2012 14:22

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