RESUMO
Two major hurdles to the widespread use of synthetic nucleic acids as drugs are the biological stability of the compounds and efficiency of cellular penetration. Recent advances in the chemistry of nucleic acids has given rise to highly stable derivatives with an anhydrohexitol backbone. This report addresses the cellular uptake of these molecules. We show that the uptake of HNA in the absence of a carrier is very low but HNA is efficiently internalized with a range of transfection reagents.
Assuntos
Hexosefosfatos/metabolismo , Ácidos Nucleicos/metabolismo , Oligonucleotídeos Antissenso/metabolismo , Corantes Fluorescentes , Células HeLa , Humanos , Ribonuclease H/biossínteseRESUMO
Hexitol nucleic acids (HNAs) with modified bases (5-methylcytosine, 2,6-diaminopurine or uracil) were synthesized. The introduction of the 5-methylcytosine base demonstrates that N -benzoylated 5-methylcytosyl-hexitol occurs as the imino tautomer. The base pairing systems (G:CMe, U:D, T:D and U:A) obey Watson-Crick rules. Substituting hT for hU, hCMefor hC and hD for hA generally leads to increased duplex stability. In a single case, replacement of hC by hCMedid not result in duplex stabilization. This sequence-specific effect could be explained by the geometry of the model duplex used for carrying out the thermal stability study. Generally, polypurine HNA sequences give more stable duplexes with their RNA complement than polypyrimidine HNA sequences. This observation supports the hypothesis that, besides changes in stacking pattern, the difference in conformational stress between purine and pyrimidine nucleosides may contribute to duplex stability. Introduction of hCMeand hD in HNA sequences further increases the potential of HNA to function as a steric blocking agent.
Assuntos
2-Aminopurina/análogos & derivados , Pareamento de Bases , Citosina/análogos & derivados , Nucleosídeos/química , Uracila/análogos & derivados , 2-Aminopurina/química , 5-Metilcitosina , Arabinonucleosídeos/química , Citosina/química , Modelos Moleculares , Desnaturação de Ácido Nucleico , Oligonucleotídeos/síntese química , Nucleosídeos de Purina/química , Nucleosídeos de Pirimidina/química , Álcoois Açúcares/químicaRESUMO
Hexitol nucleic acids (HNAs) are DNA analogues that contain the standard nucleoside bases attached to a phosphorylated 1,5-anhydrohexitol backbone. We find that HNAs support efficient information transfer in nonensymatic template-directed reactions. HNA heterosequences appeared to be superior to the corresponding DNA heterosequences in facilitating synthesis of complementary oligonucleotides from nucleoside-5'-phosphoro-2-methyl imidazolides.