| Autor: |
Sajek M; Institute of Human Genetics, Polish Academy of Sciences, Strzeszyńska 32, 60-479, Poznan, Poland., Janecki DM; Institute of Human Genetics, Polish Academy of Sciences, Strzeszyńska 32, 60-479, Poznan, Poland., Smialek MJ; Institute of Human Genetics, Polish Academy of Sciences, Strzeszyńska 32, 60-479, Poznan, Poland., Ginter-Matuszewska B; Institute of Human Genetics, Polish Academy of Sciences, Strzeszyńska 32, 60-479, Poznan, Poland. bginter@man.poznan.pl.; Department of Histology and Embryology, University of Medical Sciences, Poznań, Poland. bginter@man.poznan.pl., Spik A; Institute of Human Genetics, Polish Academy of Sciences, Strzeszyńska 32, 60-479, Poznan, Poland., Oczkowski S; Institute of Computing Sciences, Poznan University of Technology, Poznan, Poland., Ilaslan E; Institute of Human Genetics, Polish Academy of Sciences, Strzeszyńska 32, 60-479, Poznan, Poland., Kusz-Zamelczyk K; Institute of Human Genetics, Polish Academy of Sciences, Strzeszyńska 32, 60-479, Poznan, Poland., Kotecki M; Institute of Human Genetics, Polish Academy of Sciences, Strzeszyńska 32, 60-479, Poznan, Poland.; Department of Developmental, Molecular and Chemical Biology, Tufts University Medical School, Boston, MA, USA., Blazewicz J; Institute of Computing Sciences, Poznan University of Technology, Poznan, Poland.; Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland., Jaruzelska J; Institute of Human Genetics, Polish Academy of Sciences, Strzeszyńska 32, 60-479, Poznan, Poland. jadwiga.jaruzelska@igcz.poznan.pl. |
| Abstrakt: |
Pumilio (PUM) proteins are RNA-binding proteins that posttranscriptionally regulate gene expression in many organisms. Their PUF domain recognizes specific PUM-binding elements (PBE) in the 3' untranslated region of target mRNAs while engaging protein cofactors such as NANOS that repress the expression of target mRNAs through the recruitment of effector complexes. Although the general process whereby PUM recognizes individual mRNAs has been studied extensively, the particulars of the mechanism underlying PUM-NANOS cooperation in mRNA regulation and the functional overlap among PUM and NANOS paralogues in mammals have not been elucidated. Here, using the novel PUM1 and PUM2 mRNA target SIAH1 as a model, we show mechanistic differences between PUM1 and PUM2 and between NANOS1, 2, and 3 paralogues in the regulation of SIAH1. Specifically, unlike PUM2, PUM1 exhibited PBE-independent repression of SIAH1 3'UTR-dependent luciferase expression. Concordantly, the PUF domains of PUM1 and PUM2 showed different EMSA complex formation patterns with SIAH1 3'UTRs. Importantly, we show direct binding of NANOS3, but not NANOS2, to SIAH1 3'UTR, which did not require PBEs or the PUF domain. To the best of our knowledge, this is the first report, showing that an NANOS protein directly binds RNA. Finally, using NANOS1 and NANOS3 constructs carrying mutations identified in infertile patients, we show that these mutations disrupt repression of the SIAH1-luciferase reporter and that the central region in NANOS1 appears to contribute to the regulation of SIAH1. Our findings highlight the mechanistic versatility of the PUM/NANOS machinery in mammalian posttranscriptional regulation. |
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