Werner was originally identified as a protein that interacts with the product of the Werner syndrome (WS) gene, WRN. To examine the function of the WRNIP1/WRN complex in cells, we generated knock-out cell lines that were deficient in either WRN (WRN(-/-)), WRNIP1 (WRNIP10(-/-/-)), or both (WRNIP1(-/-/-)/WRN(-/-)), using a chicken B lymphocyte cell line, DT40. WRNIP1(-/-/-)/WRN(-/-) DT40 cells grew at a similar rate as wild-type cells, but the rate of spontaneous sister-chromatid exchange was augmented compared to that of either of the single mutant cell lines. Moreover, while WRNIP1(-/-/-) and WRN(-/-) cells were moderately sensitive to camptothecin (CPT), double mutant cells showed a synergistic increase in CPT sensitivity. This suggested that WRNIP1 and WRN do not always function cooperatively to repair DNA lesions. The lack of a discernable functional interaction between WRNIP1 and WRN prompted us to reevaluate the nature of the physical interaction between these proteins. We found that MBP-tagged WRNIP1 interacted directly with WRN, and that the interaction was enhanced by the addition of ATP. Mutations in the Walker A motifs of the two proteins revealed that WRNIP1, but not WRN, must bind ATP before an efficient interaction can occur.
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http://dx.doi.org/10.1016/j.dnarep.2006.04.006 | DOI Listing |
Genes Dev
April 2024
Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, Texas 77555, USA
Purified translesion synthesis (TLS) DNA polymerases (Pols) replicate through DNA lesions with a low fidelity; however, TLS operates in a predominantly error-free manner in normal human cells. To explain this incongruity, here we determine whether Y family Pols, which play an eminent role in replication through a diversity of DNA lesions, are incorporated into a multiprotein ensemble and whether the intrinsically high error rate of the TLS Pol is ameliorated by the components in the ensemble. To this end, we provide evidence for an indispensable role of Werner syndrome protein (WRN) and WRN-interacting protein 1 (WRNIP1) in Rev1-dependent TLS by Y family Polη, Polι, or Polκ and show that WRN, WRNIP1, and Rev1 assemble together with Y family Pols in response to DNA damage.
View Article and Find Full Text PDFInt J Mol Sci
January 2022
Department of Environment and Health, Section of Mechanisms Biomarkers and Models, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
Maintenance of genome stability is crucial for cell survival and relies on accurate DNA replication. However, replication fork progression is under constant attack from different exogenous and endogenous factors that can give rise to replication stress, a source of genomic instability and a notable hallmark of pre-cancerous and cancerous cells. Notably, one of the major natural threats for DNA replication is transcription.
View Article and Find Full Text PDFCancers (Basel)
February 2020
Department of Environment and Health, Section of Mechanisms Biomarkers and Models, Istituto Superiore di Sanita', Viale Regina Elena 299, 00161 Rome, Italy.
Conflicts between replication and transcription are a common source of genomic instability, a characteristic of almost all human cancers. Aberrant R-loops can cause a block to replication fork progression. A growing number of factors are involved in the resolution of these harmful structures and many perhaps are still unknown.
View Article and Find Full Text PDFJ Biol Chem
January 2020
Chromosome Dynamics Group, Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro 3, 28029 Madrid, Spain. Electronic address:
Cohesin is a chromatin-bound complex that mediates sister chromatid cohesion and facilitates long-range interactions through DNA looping. How the transcription and replication machineries deal with the presence of cohesin on chromatin remains unclear. The dynamic association of cohesin with chromatin depends on WAPL cohesin release factor (WAPL) and on PDS5 cohesin-associated factor (PDS5), which exists in two versions in vertebrate cells, PDS5A and PDS5B.
View Article and Find Full Text PDFBiol Pharm Bull
September 2019
Laboratory of Biochemistry, Faculty of Pharmaceutical Sciences, Tohoku Medical and Pharmaceutical University.
Werner helicase-interacting protein 1 (WRNIP1) was originally identified as a protein that interacts with WRN, the product of the gene responsible for Werner syndrome. Our previous studies suggested that WRNIP1 is implicated in translesion synthesis (TLS), a process in which specialized TLS polymerases replace replicative DNA polymerase and take over DNA synthesis on damaged templates. We proposed that a novel error-free pathway involving DNA polymerase δ and primase-polymerase (PrimPol) functions to synthesize DNA on UV-damaged DNA templates in the absence of WRNIP1 and the TLS polymerase Polη.
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