Human SUV3 helicase regulates growth rate of the HeLa cells and can localize in the nucleoli

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

The 42nd Symposium Chromatographic Methods of Investigating Organic Compounds : Book of abstracts

The 42nd Symposium Chromatographic Methods of Investigating Organic Compounds : Book of abstracts. June 4-7, 2019, Szczyrk, Polan

The human Suv3 helicase interacts with replication protein A and flap endonuclease 1 in the nucleus

The human Suv3 helicase has been shown to be a major player in mitochondrial RNA surveillance and decay. In the present study we identify two new interaction partners of hSUV3: the RPA (replication protein A0 and FEN1 (flap endonuclease). Another single-strand-binding protein, mtSSB fails to affect hSUV3 activity. Flap endonuclease activity of FEN1 is stimulated by hSUV3 independenttly of flap length. SUV3 may play a significant role in nuclear DNA metabolism

Human Suv3 protein reveals its unique features among SF2 helicases

Suv3 is a helicase involved in efficient turnover and surveillance of RNA in eukaryotes. In vitro study shows that human Suv3 (hSuv3) in complex with human polynucleotide phosphorylase has RNA degradosome activity. The enzyme is mainly localized in mitochondria; but small fractions are found in cell nuclei. Here we present two X-ray crystallographic structures of human Suv3 in complex with AMPPNP, a non-hydrolysable analog of ATP, and with a short five-nucleotide strand of RNA, at a resolution of 2.08 and 2.9 Å, respectively. The structure of the enzyme is very similar in the two complexes and consists of four domains. Two RecA-like domains form a tandem typical for all helicases from the SF2 superfamily which, together with the C-terminal all-helix domain, makes a ring structure through which the nucleotide strand threads. The N-terminal, mostly helical, domain is positioned externally with respect to the core of the enzyme. Most of the typical helicase motifs are present in hSuv3, but the protein shows certain unique characteristics, suggesting that Suv3 enzymes may constitute a separate subfamily of helicases

Human ELAC2 gene encodes the tRNAseZ responsible for mitochondrial tRNA 3’ processing which acts on precursors already cleaved by RNAseP

Accurate tRNA processing is crucial for human mitochondrial genome expression, but the mechanisms and key enzymes involved are poorly characterized. Here we demonstrate for the first time that human protein ELAC2 localizes both in mitochondria and the nucleus. Using the RNAi gene silencing in HeLa cells we show that the ELAC2 gene encodes tRNAseZ endonuclease which is responsible for the mitochondrial tRNA 3' processing in vivo. In addition we demonstrate that the order of precursor cleavage in mitochondria follows the rule that tRNase Z can only cleave molecules already processed by RNase P

Djelovanje tretmana gnojivom na intenzitet fuzarijske paleži klasa i sintezu mikotoksina u zimskoj raži

The fungi of the genus Fusarium cause Fusarium head blight (FHB), a devastating disease that reduces grain yield and quality. They also produce mycotoxins which may pose a serious threat to human and animal health. This study investigated the effects of NPK fertilisation, foliar application of Cu, Zn, and Mn, applied separately and in combination, and of the Nano-Gro® organic growth stimulator on the occurrence of FHB in cultivar Dańkowskie Diament rye based on the mycological analysis of kernels and on the concentrations of Fusarium mycotoxins in grain. The severity of FHB caused by seven species of the genus Fusarium was influenced by weather conditions in the analysed growing seasons. The applied fertilisation and the Nano-Gro® organic growth stimulator exerted varied effects on FHB development and the biosynthesis of Fusarium mycotoxins (deoxynivalenol, nivalenol, zearalenone and fumonisins) in grain. The greatest reduction in deoxynivalenol and nivalenol concentrations was noted in 2013, and the levels of moniliformin were lower in treated samples than in absolute control (untreated) samples in both years of the study. The severity of FHB positively correlated with the concentrations of zearalenone, deoxynivalenol, nivalenol, and moniliformin in the grain samples. Greater accumulation of ergosterol was noted in the rye grain harvested in 2013 than in 2012, and fertiliser treatment led to higher ergosterol concentrations than did control treatment.Gljivice iz roda Fusarium uzrokuju fuzarijsku palež klasa, bolest žitarica koja uništava urod i kakvoću zrna. Osim toga, ove gljivice proizvode mikotoksine koji mogu ozbiljno ugroziti zdravlje ljudi i životinja. Istražili smo djelovanje NPK gnojiva, organskoga stimulatora rasta Nano-Gro® te lisne primjene Cu, Zn i Mn, zasebno ili u kombinaciji, na učestalost fuzarijske paleži klasa u zimskoj raži (kultivar Dańkowskie Diament) na temelju mikološke analize zrnja i koncentracije fuzarijskih mikotoksina u njima. Na intenzitet bolesti zrnja koju uzrokuje sedam vrsta Fusarium gljivica ponajviše su utjecale vremenske prilike u analiziranim razdobljima. Primijenjena gnojiva i organski stimulator rasta Nano-Gro® iskazali su različite učinke na razvoj fuzarijske paleži klasa i biosintezu fuzarijskih mikotoksina (deoksinivalenola, nivalenola, zearalenona i fumonizina) u zrnju. U 2013. najveći je pad zabilježen u razinama deoksinivalenola i nivalenola, dok su razine moniliformina bile niže u tretiranim nego u netretiranim uzorcima (apsolutna kontrola) u obje godine istraživanja. Intenzitet fuzarijske paleži klasa korelirao je s koncentracijama zearalenona, deoksinivalenola, nivalenola i moniliformina u uzorcima zrnja. Do izrazitijeg nakupljanja ergosterola došlo je u raži iz žetve 2013. u odnosu na 2012. godinu, a tretman gnojivom dodatno je povisio razine ergosterola u odnosu na kontrolu