Navegando por Autor "Cnossen, Elismar de Jesus Nunes"

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    Seleção e caracterização de aptâmeros de RNA ligantes a regiao 5’-UTR do genoma do virus da dengue
    (Universidade Federal de Goiás, 2014-01-21) Cnossen, Elismar de Jesus Nunes; Marangoni, Karina; Neves, Adriana Freitas; http://lattes.cnpq.br/2984939300978146; Neves, Adriana Freitas; Madurro, João Marcos; Santos, Maria Rita de Cássia
    The increasing number of notifications of dengue infections is becoming a very important concern for global healthcare programs. Combinatorial technologies aiming the selection of specific short conformational nucleic acid ligands against viral targets, also called aptamers, can be achieved by large-scale selections using the genomic SELEX technology. Our hypothesis is that aptamers can be directly selected against dengue RNA conformational structures that present functional elements in the 5'-UTR sequence, which form RNA-RNA and protein- RNA interactions, and play significant roles in the infection process. Our aim was to select and characterize aptamers that bind to the 5’-UTR using the matrix-free SELEX method. Products from the eighth selection cycle were isolated, cloned and sequenced, and 14 ligands were chosen for in silico characterization. Aptamers were grouped into three families according to their sequence homology, and conserved ribonucleotides generated specific linear motifs. Sequences motifs were detected in random nucleotides regions ranging from 31 to 40 nt, which showed higher affinity to DENV1 and 3 virus. The novel molecules and processes described in this study open new insights for dengue research and applications, and the selected aptamers can be used either as diagnostic or therapeutic tools. In silico analyses revealed that aptamer binding to its RNA target may lead to alterations of viral RNA secondary structures, and is probably leading to the loss of its original conformational and preventing its replication and/or the transcription process. The analyses also demonstrated that aptamers presented a broad hybridization spectrum to DENV1 and 3 even in the presence of mutations in different subtypes, which suggest its possible use in the other two serotypes, DENV2 and 4. This is the first description of aptamers against the RNA structure of Dengue Virus with important implications in the disease control.