Biochemical characterization of the WRN-FEN-1 functional interaction.

Abstract

Werner Syndrome is a premature aging disorder characterized by chromosomal instability. Recently we reported a novel interaction of the WRN gene product with human 5' flap endonuclease/5'-3' exonuclease (FEN-1), a DNA structure-specific nuclease implicated in pathways of DNA metabolism that are important for genomic stability. To characterize the mechanism for WRN stimulation of FEN-1 cleavage, we have determined the effect of WRN on the kinetic parameters of the FEN-1 cleavage reaction. WRN enhanced the efficiency of FEN-1 cleavage rather than DNA substrate binding. WRN effectively stimulated FEN-1 cleavage on a flap DNA substrate with streptavidin bound to the terminal 3' nucleotide at the end of the upstream duplex, indicating that WRN does not require a free upstream end to stimulate FEN-1 cleavage of the 5' flap substrate. These results indicate that the mechanism whereby WRN stimulates FEN-1 cleavage is distinct from that proposed for the functional interaction between proliferating cell nuclear antigen and FEN-1. To understand the potential importance of the WRN-FEN-1(1) interaction in DNA replication, we have tested the effect of WRN on FEN-1 cleavage of several DNA substrate intermediates that may arise during Okazaki fragment processing. WRN stimulated FEN-1 cleavage of flap substrates with a terminal monoribonucleotide, a long 5' ssDNA tract, and a pseudo-Y structure. The ability of WRN to facilitate FEN-1 cleavage of DNA replication/repair intermediates may be important for the role of WRN in the maintenance of genomic stability.

• Authors: Robert M Brosh Jr, Henry C Driscoll, Grigory L Dianov, Joshua A Sommers
• Journal: Biochemistry (Biochemistry) Vol. 41 Issue 40 Pg. 12204-16 (Oct 08 2002) ISSN: 0006-2960 [Print] United States
• PMID: 12356323 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Biotin
• DNA
• Streptavidin
• Endodeoxyribonucleases
• Exodeoxyribonucleases
• Flap Endonucleases
• FEN1 protein, human
• DNA Helicases
• RecQ Helicases
• WRN protein, human
• Werner Syndrome Helicase

Topics

• Biotin (metabolism)
• DNA (metabolism)
• DNA Helicases (chemistry, metabolism)
• Endodeoxyribonucleases (chemistry, metabolism)
• Exodeoxyribonucleases
• Flap Endonucleases
• Humans
• Kinetics
• RecQ Helicases
• Streptavidin (metabolism)
• Werner Syndrome (metabolism)
• Werner Syndrome Helicase