1 research outputs found
Az RNS silencing szerepe, mechanizmusa a vĂrus gazda kölcsönhatásban = The role and the mechanism of RNA silencing in the plant virus interplay
Az RNS silencing, egy gĂ©ninaktiváciĂłs mechanizmus, amely szinte az összes eukariĂłta szervezetben működik. Kutatásaink során feltártuk a Cymbidium ringspot vĂrus genomrĂłl kĂ©zĹ‘dĹ‘ small interferálĂł (si) RNS eredetĂ©t nagy hatĂ©konyságĂş 454 (Life Science) Ă©s Soplexa (illumina) szekvenalĂł rendszerek alkalmazásával. A vĂrus genomrĂłl származĂł kis RNS-eket rátĂ©rkĂ©peztĂĽk a vĂrus genomjára, amely alapján "forrĂł pontokat" tudtunk azonosĂtani. Igazoltuk,hogy virus siRNS-ek tĂşlnyomĂł töbsĂ©ge a virus pozitĂv szálárĂłl származik, Ă©s 21-22 nukleotid (nt) hosszĂş. MegállapĂtottuk, hogy vĂrus siRNS-ekkel töltött RISC (RNA Induced Silencing Complex) komplexek szekvenciaspecifikusan hasĂtják a vĂrus genomot. Számos silencing szupresszor fehĂ©rje (p19, HC-Pro, Ă©s p122) rĂ©szletes analĂzisĂ©vel igazoltuk, hogy a növĂ©ny antivirális válaszát, a vĂrus kĂłdolta silencing szupresszorok hatĂ©konyan gátolják. BizonyĂtottuk, hogy a siRNS-ek specifikus kötĂ©se Ă©s inaktiválása a legelterjedtebb stratĂ©gia a silencing szupresszor fehĂ©rjĂ©k között. Feltártuk, hogy a silencing szuppresszor fehĂ©rjĂ©k egy jelentĹ‘s csoportja gátolja növĂ©nyek endogĂ©n siRNS Ă©s miRNS biogenezisĂ©t. A silencing szupressor feherjĂ©k interakciĂłja az endogen silencing Ăştvonalakkal feltehetĹ‘en a magyarázata a vĂrus okozta tĂĽnetek kialakulásának, hiszen a szupresszor fehĂ©rjĂ©k sĂşlyosan zavarja növĂ©ny egyedfejlĹ‘dĂ©sĂ©t. | RNA silencing is a gene inactivation mechanism, which is conserved in a broad range of eukaryotes. The central players in RNA-mediated gene silencing are the small 21-24 nucleotide long RNA molecules engaged in sequence-specific interactions to inhibit gene expression. RNA silencing fulfils fundamental regulatory roles, as well as antiviral functions. We profiled viral siRNAs using two different high-throughput sequencing platforms. Both deep sequencing techniques revealed a strong bias in viral siRNAs for the positive strand of the virus and identified regions on the viral genome that produced viral siRNA in much higher abundance than other regions. We also analysed the viral RNA targeting by virus induced gene silencing in tombusvirus infected plants, and we show evidence that antiviral response is based on viral RNA cleavage by RNA-induced silencing effector complex (RISC) programmed by virus-specific siRNAs.. To counteract RNA silencing, viruses express silencing suppressors that interfere with both siRNA- and microRNA-guided silencing pathways. We used comparative approaches to analyse the molecular mechanism of suppression by three well-studied silencing suppressors. We found that silencing suppressors p19, p21 and HC-Pro each inhibit the RISC assembly. We demonstrated that these suppressors are able to interact with the endogenous silencing pathways suggesting that these interactions have an important role in the development of virus-induced symptoms