» Articles » PMID: 31435650

Molecular Characteristics of Reiterative DNA Unwinding by the Caenorhabditis Elegans RecQ Helicase

Overview
Specialty Biochemistry
Date 2019 Aug 23
PMID 31435650
Citations 5
Authors
Affiliations
Soon will be listed here.
Abstract

The RecQ family of helicases is highly conserved both structurally and functionally from bacteria to humans. Defects in human RecQ helicases are associated with genetic diseases that are characterized by cancer predisposition and/or premature aging. RecQ proteins exhibit 3'-5' helicase activity and play critical roles in genome maintenance. Recent advances in single-molecule techniques have revealed the reiterative unwinding behavior of RecQ helicases. However, the molecular mechanisms involved in this process remain unclear, with contradicting reports. Here, we characterized the unwinding dynamics of the Caenorhabditis elegans RecQ helicase HIM-6 using single-molecule fluorescence resonance energy transfer measurements. We found that HIM-6 exhibits reiterative DNA unwinding and the length of DNA unwound by the helicase is sharply defined at 25-31 bp. Experiments using various DNA substrates revealed that HIM-6 utilizes the mode of 'sliding back' on the translocated strand, without strand-switching for rewinding. Furthermore, we found that Caenorhabditis elegans replication protein A, a single-stranded DNA binding protein, suppresses the reiterative behavior of HIM-6 and induces unidirectional, processive unwinding, possibly through a direct interaction between the proteins. Our findings shed new light on the mechanism of DNA unwinding by RecQ family helicases and their co-operation with RPA in processing DNA.

Citing Articles

Werner syndrome protein works as a dimer for unwinding and replication fork regression.

Shin S, Hyun K, Lee J, Joo D, Kulikowicz T, Bohr V Nucleic Acids Res. 2022; 51(1):337-348.

PMID: 36583333 PMC: 9841404. DOI: 10.1093/nar/gkac1200.


DNA repair, recombination, and damage signaling.

Gartner A, Engebrecht J Genetics. 2022; 220(2).

PMID: 35137093 PMC: 9097270. DOI: 10.1093/genetics/iyab178.


Dynamics of the PriA Helicase at Stalled DNA Replication Forks.

Sun Z, Wang Y, Bianco P, Lyubchenko Y J Phys Chem B. 2021; 125(17):4299-4307.

PMID: 33881864 PMC: 9596136. DOI: 10.1021/acs.jpcb.0c11225.


The HRDC domain oppositely modulates the unwinding activity of E. coli RecQ helicase on duplex DNA and G-quadruplex.

Teng F, Wang T, Guo H, Xin B, Sun B, Dou S J Biol Chem. 2021; 295(51):17646-17658.

PMID: 33454004 PMC: 7762929. DOI: 10.1074/jbc.RA120.015492.


Branched unwinding mechanism of the Pif1 family of DNA helicases.

Singh S, Soranno A, Sparks M, Galletto R Proc Natl Acad Sci U S A. 2019; 116(49):24533-24541.

PMID: 31744872 PMC: 6900637. DOI: 10.1073/pnas.1915654116.

References
1.
Kim D, Lee K, Kim J, Ryu G, Bae S, Lee B . Enzymatic properties of the Caenorhabditis elegans Dna2 endonuclease/helicase and a species-specific interaction between RPA and Dna2. Nucleic Acids Res. 2005; 33(4):1372-83. PMC: 552954. DOI: 10.1093/nar/gki255. View

2.
Lee S, Yook J, Han S, Koo H . A Werner syndrome protein homolog affects C. elegans development, growth rate, life span and sensitivity to DNA damage by acting at a DNA damage checkpoint. Development. 2004; 131(11):2565-75. DOI: 10.1242/dev.01136. View

3.
Grabowski M, Svrzikapa N, Tissenbaum H . Bloom syndrome ortholog HIM-6 maintains genomic stability in C. elegans. Mech Ageing Dev. 2005; 126(12):1314-21. DOI: 10.1016/j.mad.2005.08.005. View

4.
Kim H, Abeysirigunawarden S, Chen K, Mayerle M, Ragunathan K, Luthey-Schulten Z . Protein-guided RNA dynamics during early ribosome assembly. Nature. 2014; 506(7488):334-8. PMC: 3968076. DOI: 10.1038/nature13039. View

5.
Brosh Jr R, Li J, Kenny M, Karow J, Cooper M, Kureekattil R . Replication protein A physically interacts with the Bloom's syndrome protein and stimulates its helicase activity. J Biol Chem. 2000; 275(31):23500-8. DOI: 10.1074/jbc.M001557200. View