title: Expression and localization of Werner syndrome protein is modulated by SIRT1 and PML.
abstract: Mutations in genes for WRN and BLM RecQ family helicases cause cancer prone syndromes. Werner syndrome, resulting from WRN mutation, is a segmental progeria. Endogenous WRN and BLM proteins localize in nucleoli and in nuclear PML bodies defined by isoforms of the PML protein, which is a key regulator of cellular senescence. We further characterized WRN and BLM localization using labeling with monomeric red fluorescence protein (mRFP). When ectopically expressed, mRFP-WRN (or untagged WRN) forms nuclear bodies, which are donut-shaped in some cells. We identified PML isoforms associating with the nuclear bodies. Interestingly, mRFP-WRN relocalizes from nucleoli to the nucleoplasm, frequently showing conspicuous nucleolar exclusion as well as a decrease in frequency of mRFP-WRN nuclear bodies in response to overexpression of wild-type and deacetylase mutant (H363Y) SIRT1 proteins. Similar nucleolar relocalization in response to wild-type SIRT1 was detected for mRFP-labeled BLM. Moreover, increased SIRT1 expression was associated with the downregulation of endogenous WRN and a decreased frequency of cells with BRCA1 foci. Our data indicate for the first time that SIRT1 protein may be functionally associated with WRN and BLM helicases and that some major SIRT1 functions may not require its deacetylase activity.
authors.affiliation: Department of Tumor Biology, Maria Skłodowska - Curie Memorial Cancer Center, ul. Wybrzeze Armii Krajowej 15, 44-101 Gliwice, Poland.
authors.forename: Rasa
authors.initials: R
authors.lastname: Vaitiekunaite
authors.forename: Dorota
authors.initials: D
authors.lastname: Butkiewicz
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Krześniak
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Przybyłek
authors.forename: Agata
authors.initials: A
authors.lastname: Gryc
authors.forename: Mirosław
authors.initials: M
authors.lastname: Snietura
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Benedyk
authors.forename: Curtis C
authors.initials: CC
authors.lastname: Harris
authors.forename: Marek
authors.initials: M
authors.lastname: Rusin
mesh_terms: D000107:Acetylation; D000251:Adenosine Triphosphatases / Q000378:metabolism; D019313:BRCA1 Protein / Q000378:metabolism; D045744:Cell Line, Tumor; D002466:Cell Nucleolus / Q000378:metabolism; D002467:Cell Nucleus / Q000201:enzymology / Q000378:metabolism*; D016922:Cellular Senescence; D004265:DNA Helicases / Q000378:metabolism; D005090:Exodeoxyribonucleases; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D000071156:Promyelocytic Leukemia Protein; D021381:Protein Transport; D053484:RecQ Helicases / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D056564:Sirtuin 1; D037761:Sirtuins / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D000071657:Werner Syndrome Helicase; D000097573:Red Fluorescent Protein
chemical_list: D000251:Adenosine Triphosphatases; D019313:BRCA1 Protein; D004265:DNA Helicases; D005090:Exodeoxyribonucleases; D008164:Luminescent Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D000071156:Promyelocytic Leukemia Protein; D053484:RecQ Helicases; D011993:Recombinant Fusion Proteins; D056564:Sirtuin 1; D037761:Sirtuins; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D000071657:Werner Syndrome Helicase; D000097573:Red Fluorescent Protein; C492913:BRCA1 protein, human; C070576:PML protein, human; C447939:SIRT1 protein, human; C097151:Bloom syndrome protein; C098785:WRN protein, human