Short synthetic oligonucleotides are valuable tools as they find applications in numerous fields including nanotechnology, molecular biology, biotechnology, and clinical diagnostics. From a chemical standpoint, oligonucleotides are polymers built of four nucleotide molecules abbreviated A, T, C and G in deoxyribonucleic acid (DNA), and A, U, C and G in ribonucleic acid (RNA). Oligonucleotide probes can be designed to target any desired part of genome, using a fundamental Watson-Crick base-pairing rule, which is A binds T/U and C binds G. However, translation from bench side to practical applications requires the development of chemically modified oligonucleotide sequences that are gene specific, chemically, enzymatically stable, and efficiently internalized by target cells.
This PhD study focuses on synthesis and characterization of new modified oligonucleotides as potent diagnostic and therapeutic candidates. The project contributes with several modifications that improve properties of short synthetic oligonucleotides. Given a broad applicability of DNA and RNA analogues, this work might contribute to advanced diagnostic and therapeutic tools.
First, the study includes synthesis of a small library of peptide-oligonucleotide conjugates (POCs) and investigation of their biophysical properties. The findings confirmed the POCs ability for efficient target binding and single nucleotide polymorphism (SNP) discrimination. Additionally, the serum stability studies confirmed higher stability of the POCs when compared with the naked-parent oligonucleotides. Finally, the research formulated complexed and conjugated oligonucleotide therapeutics with peptide sequences, designed to reduce the HIV1-mRNA or the BGas lnRNA expression and function. The cell culture experiments showed promising effect and cell internalization for the complexes and conjugates. Nevertheless, the variability within the quantitative results was high.
In addition, a part of this PhD study concentrates on the synthesis of multifluorophore labelled oligonucleotides for detection human genes.
siRNA mechanism of action.