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  1. Article ; Online: Identification of the nuclear localization signal in the Saccharomyces cerevisiae Pif1 DNA helicase.

    Lee, Rosemary S / Geronimo, Carly L / Liu, Liping / Twarowski, Jerzy M / Malkova, Anna / Zakian, Virginia A

    PLoS genetics

    2023  Volume 19, Issue 7, Page(s) e1010853

    Abstract: Saccharomyces cerevisiae Pif1 is a multi-functional DNA helicase that plays diverse roles in the maintenance of the nuclear and mitochondrial genomes. Two isoforms of Pif1 are generated from a single open reading frame by the use of alternative ... ...

    Abstract Saccharomyces cerevisiae Pif1 is a multi-functional DNA helicase that plays diverse roles in the maintenance of the nuclear and mitochondrial genomes. Two isoforms of Pif1 are generated from a single open reading frame by the use of alternative translational start sites. The Mitochondrial Targeting Signal (MTS) of Pif1 is located between the two start sites, but a Nuclear Localization Signal (NLS) has not been identified. Here we used sequence and functional analysis to identify an NLS element. A mutant allele of PIF1 (pif1-NLSΔ) that lacks four basic amino acids (781KKRK784) in the carboxyl-terminal domain of the 859 amino acid Pif1 was expressed at wild type levels and retained wild type mitochondrial function. However, pif1-NLSΔ cells were defective in four tests for nuclear function: telomere length maintenance, Okazaki fragment processing, break-induced replication (BIR), and binding to nuclear target sites. Fusing the NLS from the simian virus 40 (SV40) T-antigen to the Pif1-NLSΔ protein reduced the nuclear defects of pif1-NLSΔ cells. Thus, four basic amino acids near the carboxyl end of Pif1 are required for the vast majority of nuclear Pif1 function. Our study also reveals phenotypic differences between the previously described loss of function pif1-m2 allele and three other pif1 mutant alleles generated in this work, which will be useful to study nuclear Pif1 functions.
    MeSH term(s) Saccharomyces cerevisiae/genetics ; Saccharomyces cerevisiae/metabolism ; DNA Replication ; Nuclear Localization Signals/genetics ; Nuclear Localization Signals/metabolism ; Saccharomyces cerevisiae Proteins/metabolism ; DNA Helicases/genetics ; DNA Helicases/metabolism
    Chemical Substances Nuclear Localization Signals ; Saccharomyces cerevisiae Proteins ; DNA Helicases (EC 3.6.4.-) ; PIF1 protein, S cerevisiae (EC 3.6.1.-)
    Language English
    Publishing date 2023-07-24
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 2186725-2
    ISSN 1553-7404 ; 1553-7390
    ISSN (online) 1553-7404
    ISSN 1553-7390
    DOI 10.1371/journal.pgen.1010853
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Getting it done at the ends: Pif1 family DNA helicases and telomeres.

    Geronimo, Carly L / Zakian, Virginia A

    DNA repair

    2016  Volume 44, Page(s) 151–158

    Abstract: It is widely appreciated that the ends of linear DNA molecules cannot be fully replicated by the conventional replication apparatus. Less well known is that semi-conservative replication of telomeric DNA also presents problems for DNA replication. These ... ...

    Abstract It is widely appreciated that the ends of linear DNA molecules cannot be fully replicated by the conventional replication apparatus. Less well known is that semi-conservative replication of telomeric DNA also presents problems for DNA replication. These problems likely arise from the atypical chromatin structure of telomeres, the GC-richness of telomeric DNA that makes it prone to forming DNA secondary structures, and from RNA-DNA hybrids, formed by transcripts of one or both DNA strands. Given the different aspects of telomeres that complicate their replication, it is not surprising that multiple DNA helicases promote replication of telomeric DNA. This review focuses on one such class of DNA helicases, the Pif1 family of 5'-3' DNA helicases. In budding and fission yeasts, Pif1 family helicases impact both telomerase-mediated and semi-conservative replication of telomeric DNA as well as recombination-mediated telomere lengthening.
    MeSH term(s) Base Pairing ; Chromatin/metabolism ; Chromatin/ultrastructure ; DNA/genetics ; DNA/metabolism ; DNA Helicases/genetics ; DNA Helicases/metabolism ; DNA Replication ; Humans ; Multigene Family ; Nucleic Acid Conformation ; RNA, Messenger/genetics ; RNA, Messenger/metabolism ; Recombination, Genetic ; Saccharomyces cerevisiae/genetics ; Saccharomyces cerevisiae/metabolism ; Saccharomyces cerevisiae Proteins/genetics ; Saccharomyces cerevisiae Proteins/metabolism ; Schizosaccharomyces/genetics ; Schizosaccharomyces/metabolism ; Telomere/metabolism ; Telomere/ultrastructure ; Telomere Homeostasis
    Chemical Substances Chromatin ; RNA, Messenger ; Saccharomyces cerevisiae Proteins ; DNA (9007-49-2) ; PIF1 protein, S cerevisiae (EC 3.6.1.-) ; Rrm3 protein, S cerevisiae (EC 3.6.1.-) ; DNA Helicases (EC 3.6.4.-)
    Language English
    Publishing date 2016-08
    Publishing country Netherlands
    Document type Journal Article ; Review
    ZDB-ID 2071608-4
    ISSN 1568-7856 ; 1568-7864
    ISSN (online) 1568-7856
    ISSN 1568-7864
    DOI 10.1016/j.dnarep.2016.05.021
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 5555: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (2.OG)
    ab Jg. 2022: Lesesaal (EG)

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  3. Article ; Online: The signature motif of the Saccharomyces cerevisiae Pif1 DNA helicase is essential in vivo for mitochondrial and nuclear functions and in vitro for ATPase activity.

    Geronimo, Carly L / Singh, Saurabh P / Galletto, Roberto / Zakian, Virginia A

    Nucleic acids research

    2018  Volume 46, Issue 16, Page(s) 8357–8370

    Abstract: Pif1 family DNA helicases are conserved from bacteria to humans and have critical and diverse functions in vivo that promote genome integrity. Pif1 family helicases share a 23 amino acid region, called the Pif1 signature motif (SM) that is unique to this ...

    Abstract Pif1 family DNA helicases are conserved from bacteria to humans and have critical and diverse functions in vivo that promote genome integrity. Pif1 family helicases share a 23 amino acid region, called the Pif1 signature motif (SM) that is unique to this family. To determine the importance of the SM, we did mutational and functional analysis of the SM from the Saccharomyces cerevisiae Pif1 (ScPif1). The mutations deleted portions of the SM, made one or multiple single amino acid changes in the SM, replaced the SM with its counterpart from a bacterial Pif1 family helicase and substituted an α-helical domain from another helicase for the part of the SM that forms an α helix. Mutants were tested for maintenance of mitochondrial DNA, inhibition of telomerase at telomeres and double strand breaks, and promotion of Okazaki fragment maturation. Although certain single amino acid changes in the SM can be tolerated, the presence and sequence of the ScPif1 SM were essential for all tested in vivo functions. Consistent with the in vivo analyses, in vitro studies showed that the presence and sequence of the ScPif1 SM were critical for ATPase activity but not substrate binding.
    MeSH term(s) Adenosine Triphosphatases/genetics ; Amino Acid Motifs/genetics ; Cell Nucleus/genetics ; DNA Helicases/genetics ; DNA Replication/genetics ; Humans ; Mitochondria/genetics ; Protein Stability ; Saccharomyces cerevisiae/genetics ; Saccharomyces cerevisiae Proteins/genetics ; Sequence Deletion/genetics ; Telomerase/genetics ; Telomere/genetics
    Chemical Substances Saccharomyces cerevisiae Proteins ; Telomerase (EC 2.7.7.49) ; Adenosine Triphosphatases (EC 3.6.1.-) ; PIF1 protein, S cerevisiae (EC 3.6.1.-) ; DNA Helicases (EC 3.6.4.-)
    Language English
    Publishing date 2018-06-30
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 186809-3
    ISSN 1362-4962 ; 1362-4954 ; 0301-5610 ; 0305-1048
    ISSN (online) 1362-4962 ; 1362-4954
    ISSN 0301-5610 ; 0305-1048
    DOI 10.1093/nar/gky655
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 1067: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)

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  4. Article ; Online: HRI depletion cooperates with pharmacologic inducers to elevate fetal hemoglobin and reduce sickle cell formation.

    Peslak, Scott A / Khandros, Eugene / Huang, Peng / Lan, Xianjiang / Geronimo, Carly L / Grevet, Jeremy D / Abdulmalik, Osheiza / Zhang, Zhe / Giardine, Belinda M / Keller, Cheryl A / Shi, Junwei / Hardison, Ross C / Blobel, Gerd A

    Blood advances

    2020  Volume 4, Issue 18, Page(s) 4560–4572

    Abstract: Increasing fetal hemoglobin (HbF) provides clinical benefit in patients with sickle cell disease (SCD). We recently identified heme-regulated inhibitor (HRI, EIF2AK1), as a novel HbF regulator. Because HRI is an erythroid-specific protein kinase, it ... ...

    Abstract Increasing fetal hemoglobin (HbF) provides clinical benefit in patients with sickle cell disease (SCD). We recently identified heme-regulated inhibitor (HRI, EIF2AK1), as a novel HbF regulator. Because HRI is an erythroid-specific protein kinase, it presents a potential target for pharmacologic intervention. We found that maximal HbF induction required >80% to 85% HRI depletion. Because it remains unclear whether this degree of HRI inhibition can be achieved pharmacologically, we explored whether HRI knockdown can be combined with pharmacologic HbF inducers to achieve greater HbF production and minimize potential adverse effects associated with treatments. Strongly cooperative HbF induction was observed when HRI depletion was combined with exposure to pomalidomide or the EHMT1/2 inhibitor UNC0638, but not to hydroxyurea. Mechanistically, reduction in the levels of the HbF repressor BCL11A reflected the cooperativity of HRI loss and pomalidomide treatment, whereas UNC0638 did not modulate BCL11A levels. In conjunction with HRI loss, pomalidomide maintained its HbF-inducing activity at 10-fold lower concentrations, in which condition there were minimal observed detrimental effects on erythroid cell maturation and viability, as well as fewer alterations in the erythroid transcriptome. When tested in cells from patients with SCD, combining HRI depletion with pomalidomide or UNC0638 achieved up to 50% to 60% HbF and 45% to 50% HbF, respectively, as measured by high-performance liquid chromatography, and markedly counteracted cell sickling. In summary, this study provides a foundation for the exploration of combining future small-molecule HRI inhibitors with additional pharmacologic HbF inducers to maximize HbF production and preserve erythroid cell functionality for the treatment of SCD and other hemoglobinopathies.
    MeSH term(s) Anemia, Sickle Cell/drug therapy ; Erythrocytes, Abnormal ; Erythroid Cells ; Fetal Hemoglobin/genetics ; Humans ; Hydroxyurea/pharmacology
    Chemical Substances Fetal Hemoglobin (9034-63-3) ; Hydroxyurea (X6Q56QN5QC)
    Language English
    Publishing date 2020-09-21
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 2915908-8
    ISSN 2473-9537 ; 2473-9529
    ISSN (online) 2473-9537
    ISSN 2473-9529
    DOI 10.1182/bloodadvances.2020002475
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    Zs.A 7153: Show issues Location:
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