Ribonucleic acids are biopolymers that may fold into more than one structure in order to perform their functional tasks; the folding dynamics might lead to multiple secondary structures in long RNA molecules, since an RNA molecule might fold into multiple states not too different in energy. In the first part of the talk, we show that the end-to-end distance in different long ssRNA molecules is very small, within 5–9 nm, by means of single molecule Fluorescence Resonance Energy Transfer (smFRET). It is remarkable that the separation of the ends of all RNA molecules studied remains small and similar, despite the origin, length and differences in their secondary structure. This implies that the ssRNA molecules are “effectively circularized”, something that might be a general feature of RNA molecules, which could result in fine tuning for translation and gene expression regulation. In the second part of the talk, I will present different conformations of a small HIV-1 RNA and mutated target structures. We studied whether or not the observed conformations in the RNA-mutated target molecules expose its target sequence against a RNA-induced silencing complex (RISC), whose core was the Thermus thermophilus Argonaute (TtAgo) protein.
Again, smFRET and gel electrophoresis mobility of RNA-RISC interactions indicate that RNA punctual mutations may help the RNA target escapes being cleaved by the RISC complex. This result could indicate that mutations in RNA viruses are selective and can help them to partially scape our immune system.
Participante: Dr. Jaime Ruíz García
Institución: Universidad Autónoma de San Luis Potosí
Fecha y hora: Este evento terminó el Lunes, 06 de Mayo de 2019