Dimethoxytritylphosphono-oligonucleotide conjugates have been prepared. They are totally resistant to nucleases present in human serum and do not affect cleavage of a complementary oligoribonucleotide by RNase H. Conjugates possessing a phosphate backbone gave better antisense inhibition of expression of plasminogen activator inhibitor type-1 within endothelial cells as compared with unconjugated oligonucleotides.
Preparations of anti-DNA sIgA were obtained from human milk by sequential chromatography on protein A-sepharose, DEAE-fractogel and DNA-cellulose. The influence of oligonucleotides on protein kinase activity was investigated. It was discovered that incubation of anti-DNA sIgA with oligodeoxyriboadenylate d(A)12 stimulates the phosphorylation of polypeptides of sIgA in the presence of [γ- 32P]ATP. The greatest was the incorporation of 32P into the sIgA H-chains. We also demonstrated stimulation of the casein kinase activity of anti-DNA sIgA by d(A)12. The stimulation of the protein kinase activity of anti-DNA sIgA by oligoriboadenylate r(A)12 was not detected.
Oligonucleotides (ODNs) are short (up to 30 bases) fragments of single-stranded nucleic acids that are used as sequence specific regulators of gene expression and anti-sense based therapeutics. ODNs are frequently aggregated with particulates in order to improve their pharmacological characteristics. Complexes of ODN and lipid aggregates are among the most commonly mentioned in the literature. In order to control the formation and final properties of such aggregates, a detailed description of how ODN interacts with the lipid surface is needed. In this paper, we present the results of fluorescence measurements regarded an association of 20 base ODN, labelled with fluorescein, and a lipid surface containing various amount of positive charge. Unilamellar lipid vesicles were formed from egg phosphatidylcholine (PC) and various amounts of the cationic lipid l,2-dioleoyl-3-trimethylammonium- propane (DOTAP). It was found that about 20 mol% of DOTAP in the lipid bilayer suffices to obtain complete ODN association. This result was further confirmed via measurements performed by fluorescence correlation spectroscopy (FCS). These in turn showed that the diffusion time of labelled ODN in the presence of cationic liposomes decreases. Also, the particle number and count rate were reduced, concurring with conclusions derived from steady state fluorescence spectroscopy results.
This re view pres ents a brief ac count of the chem is try and mech a nis tic as pects of aryl H-phosphonates, and se lected ap pli ca tions of this class of com pounds as in ter me di ates in the syn the sis of a wide range of bi o log i cally im por tant an a logues of nucleoside phos phates, and oligonucleotides, in which the phos phate moi eties are re placed by other struc tur ally re lated groups. The aryl nucleosideH-phosphonates, com pounds of con trolled re ac tiv ity, have proven to be more ver sa tile and su pe rior to var i ous mixed an hy drides as syn thetic in ter me di ates, par tic u larly for prep a ra tion of nu cle o tide an a- logues bearing P-N or P-S bonds in various configurational arrangements at the phos phate moi ety.
In this study we investigated effects of bcl-2 antisense oligonucleotides (AS) and BAY K 8644 (B), calcium channel agonist, on human leukaemic cells from non-treatment patients with acute myeloblastic leukaemias. Apoptotic cells were observed in electron and fluorescent microscopes. When we examined the effects of AS + B on cells, level of bcl-2 mRNA decreased more as in cells stimulated by AS only. These observations indicate that AS with B in human leukaemic cells disturb cell viability by inducing apoptosis.