Electronic coupling between base pair dimers of LNA:DNA oligomers

Brightness through local constraint--LNA-enhanced FIT hybridization probes for in vivo ribonucleotide particle tracking

Imaging the dynamics of RNA in living cells is usually performed by means of transgenic approaches that require modification of RNA targets and cells. Fluorogenic hybridization probes would also allow the analysis of wild-type organisms. We developed nuclease-resistant DNA forced intercalation (FIT) probes that combine the high enhancement of fluorescence upon hybridization with the high brightness required to allow tracking of individual ribonucleotide particles (RNPs). In our design, a single thiazole orange (TO) intercalator dye is linked as a nucleobase surrogate and an adjacent locked nucleic acid (LNA) unit serves to introduce a local constraint. This closes fluorescence decay channels and thereby increases the brightness of the probe-target duplexes. As few as two probes were sufficient to enable the tracking of oskar mRNPs in wild-type living Drosophila melanogaster oocytes.

Dynamics and efficiency of hole transport in LNA:DNA hybrid diblock oligomers

We report here the effect of replacing one or both of the purine or pyrimidine blocks of a diblock stilbene donor-acceptor capped hairpin with locked nucleic acid (LNA) bases on the dynamics and efficiency of hole transport. The structures of the DNA and LNA:DNA hybrids are tentatively assigned to B- or A-type structures on the basis of their circular dichroism spectra. Replacing the bases in either the A-block or the G-block of the diblock DNA hairpin with LNA bases results in a modest decrease in the base-to-base hopping rate constant and quantum yield for charge separation. Somewhat larger decreases are observed when all of the purine or pyrimidine bases are replaced by LNA bases.