Physical and Functional Interactions of Caenorhabditis elegansWRN-1 Helicase with RPA-1

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• 作者：Moonjung Hyun ; Sojin Park ; Eunsun Kim ; Do-Hyung Kim ; Se-Jin Lee ; Hyeon-Sook Koo ; Yeon-Soo Seo ; Byungchan Ahn
• 刊名：Biochemistry
• 出版年：2012
• 出版时间：February 21, 2012
• 年：2012
• 卷：51
• 期：7
• 页码：1336-1345
• 全文大小：428K
• 年卷期：v.51,no.7(February 21, 2012)
• ISSN：1520-4995

文摘

The Caenorhabditis elegans Werner syndrome protein, WRN-1, a member of the RecQ helicase family, has a 3鈥测€?鈥?DNA helicase activity. Worms with defective wrn-1 exhibit premature aging phenotypes and an increased level of genome instability. In response to DNA damage, WRN-1 participates in the initial stages of checkpoint activation in concert with C. elegans replication protein A (RPA-1). WRN-1 helicase is stimulated by RPA-1 on long DNA duplex substrates. However, the mechanism by which RPA-1 stimulates DNA unwinding and the function of the WRN-1鈥揜PA-1 interaction are not clearly understood. We have found that WRN-1 physically interacts with two RPA-1 subunits, CeRPA73 and CeRPA32; however, full-length WRN-1 helicase activity is stimulated by only the CeRPA73 subunit, while the WRN-1_162鈥?056 fragment that harbors the helicase activity requires both the CeRPA73 and CeRPA32 subunits for the stimulation. We also found that the CeRPA73_1鈥?64 fragment can stimulate WRN-1 helicase activity and that residues 335鈥?64 of CeRPA73 are important for physical interaction with WRN-1. Because CeRPA73 and the CeRPA73_1鈥?64 fragment are able to bind single-stranded DNA (ssDNA), the stimulation of WRN-1 helicase by RPA-1 is most likely due to the ssDNA binding activity of CeRPA73 and the direct interaction of WRN-1 and CeRPA73.