title: Human SUV3 helicase regulates growth rate of the HeLa cells and can localize in the nucleoli.
abstract: The human SUV3 helicase (SUV3, hSUV3, SUPV3L1) is a DNA/RNA unwinding enzyme belonging to the class of DexH-box helicases. It localizes predominantly in the mitochondria, where it forms an RNA-degrading complex called mitochondrial degradosome with exonuclease PNP (polynucleotide phosphorylase). Association of this complex with the polyA polymerase can modulate mitochondrial polyA tails. Silencing of the SUV3 gene was shown to inhibit the cell cycle and to induce apoptosis in human cell lines. However, since small amounts of the SUV3 helicase were found in the cell nuclei, it was not clear whether the observed phenotypes of SUV3 depletion were of mitochondrial or nuclear origin. In order to answer this question we have designed gene constructs able to inhibit the SUV3 activity exclusively in the cell nuclei. The results indicate that the observed growth rate impairment upon SUV3 depletion is due to its nuclear function(s). Unexpectedly, overexpression of the nuclear-targeted wild-type copies of the SUV3 gene resulted in a higher growth rate. In addition, we demonstrate that the SUV3 helicase can be found in the HeLa cell nucleoli, but it is not detectable in the DNA-repair foci. Our results indicate that the nucleolar-associated human SUV3 protein is an important factor in regulation of the cell cycle.
authors.affiliation: Institute of Genetics and Biotechnology, Faculty of Biology, Warsaw University, Warsaw, Poland.
authors.forename: Maciej
authors.initials: M
authors.lastname: Szewczyk
authors.affiliation: Centre for New Technologies, University of Warsaw, Warsaw, Poland.
authors.forename: Natalia
authors.initials: N
authors.lastname: Fedoryszak-Kuśka
authors.affiliation: Institute of Genetics and Biotechnology, Faculty of Biology, Warsaw University, Warsaw, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Tkaczuk
authors.affiliation: Department of Cell Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland.
authors.forename: Jurek
authors.initials: J
authors.lastname: Dobrucki
authors.affiliation: Department of Cell Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Waligórska
authors.affiliation: Institute of Genetics and Biotechnology, Faculty of Biology, Warsaw University, Warsaw, Poland.|Institute of Biochemistry and Biophysics Polish Academy of Sciences, Warsaw, Poland.|Centre for New Technologies, University of Warsaw, Warsaw, Poland.
authors.forename: Piotr P
authors.initials: PP
authors.lastname: Stępień
mesh_terms: D017209:Apoptosis; D002453:Cell Cycle; D002466:Cell Nucleolus / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation; D053487:DEAD-box RNA Helicases / Q000502:physiology*; D004722:Endoribonucleases; D006367:HeLa Cells; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*; D009097:Multienzyme Complexes; D011117:Polyribonucleotide Nucleotidyltransferase; D020365:RNA Helicases; D014162:Transfection
chemical_list: D009097:Multienzyme Complexes; C111244:degradosome; D011117:Polyribonucleotide Nucleotidyltransferase; D004722:Endoribonucleases; C469673:SUPV3L1 protein, human; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases
keywords: SUPV3L1; SUV3 helicase; cell cycle; dual targeting; mitochondria; nucleolus