Modulation of the RNA Interference Activity Using Central Mismatched siRNAs and Acyclic Threoninol Nucleic Acids (aTNA) Units.
The understanding of the mechanisms behind nucleotide recognition by Argonaute 2, core protein of the RNA-induced silencing complex, is a key aspect in the optimization of small interfering RNAs (siRNAs) activity. To date, great efforts have been focused on the modification of certain regions of siRNA, such as the 3'/5'-termini and the seed region. Only a few reports have described the roles of central positions flanking the cleavage site during the silence process. In this study, we investigate the potential correlations between the thermodynamic and silencing properties of siRNA molecules carrying, at internal positions, an acyclic L-threoninol nucleic acid (aTNA) modification. Depending on position, the silencing is weakened or impaired. Furthermore, we evaluate the contribution of mismatches facing either a natural nucleotide or an aTNA modification to the siRNA potency. The position 11 of the antisense strand is more permissive to mismatches and aTNA modification, in respect to the position 10. Additionally, comparing the ON-/OFF-target silencing of central mismatched siRNAs with 5'-terminal modified siRNA, we concluded: (i) central perturbation of duplex pairing features weights more on potency rather than silencing asymmetry; (ii) complete bias for the ON-target silencing can be achieved with single L-threoninol modification near the 5'-end of the sense strand.
Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), CIBER-BBN Networking Centre on Bioengineering, Biomaterials and Nanomedicine, Jordi Girona 18-26, 08034 Barcelona, Spain. adele.alagia@iqac.csic.es.
Adele
A
Alagia
Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), CIBER-BBN Networking Centre on Bioengineering, Biomaterials and Nanomedicine, Jordi Girona 18-26, 08034 Barcelona, Spain. montserrat.terrazas@irbbarcelona.org.|Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, 08028 Barcelona, Spain. montserrat.terrazas@irbbarcelona.org.
Montserrat
M
Terrazas
Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), CIBER-BBN Networking Centre on Bioengineering, Biomaterials and Nanomedicine, Jordi Girona 18-26, 08034 Barcelona, Spain. recgma@cid.csic.es.
Ramon
R
Eritja
D000605:Amino Alcohols / Q000737:chemistry*; D000818:Animals; D060565:Argonaute Proteins / Q000235:genetics; D020137:Base Pair Mismatch / Q000235:genetics*; D020029:Base Pairing / Q000235:genetics; D002072:Butylene Glycols / Q000737:chemistry*; D002460:Cell Line; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D009690:Nucleic Acid Conformation; D009692:Nucleic Acid Heteroduplexes; D009696:Nucleic Acids / Q000737:chemistry*; D034622:RNA Interference / Q000502:physiology*; D034741:RNA, Small Interfering / Q000235:genetics*
C466422:AGO2 protein, human; D000605:Amino Alcohols; D060565:Argonaute Proteins; D002072:Butylene Glycols; D009692:Nucleic Acid Heteroduplexes; D009696:Nucleic Acids; D034741:RNA, Small Interfering; C532652:threoninol