Advances in Antisense Oligonucleotide Development for Target Identification, Validation, and as Novel Therapeutics

Antisense oligonucleotides (As-ODNs) are single stranded, synthetically prepared strands of deoxynucleotide sequences, usually 18–21 nucleotides in length, complementary to the mRNA sequence of the target gene. As-ODNs are able to selectively bind cognate mRNA sequences by sequence-specific hybridization. This results in cleavage or disablement of the mRNA and, thus, inhibits the expression of the target gene. The specificity of the As approach is based on the probability that, in the human genome, any sequence longer than a minimal number of nucleotides (nt), 13 for RNA and 17 for DNA, normally occurs only once. The potential applications of As-ODNs are numerous because mRNA is ubiquitous and is more accessible to manipulation than DNA. With the publication of the human genome sequence, it has become theoretically possible to inhibit mRNA of almost any gene by As-ODNs, in order to get a better understanding of gene function, investigate its role in disease pathology and to study novel therapeutic targets for the diseases caused by dysregulated gene expression. The conceptual simplicity, the availability of gene sequence information from the human genome, the inexpensive availability of synthetic oligonucleotides and the possibility of rational drug design makes As-ODNs powerful tools for target identification, validation and therapeutic intervention. In this review we discuss the latest developments in antisense oligonucleotide design, delivery, pharmacokinetics and potential side effects, as well as its uses in target identification and validation, and finally focus on the current developments of antisense oligonucleotides in therapeutic intervention in various diseases

Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events

The $B^0$-$\bar B^0$ oscillation frequency has been measured with a sample of 23 million \B\bar B pairs collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we select events in which both B mesons decay semileptonically and use the charge of the leptons to identify the flavor of each B meson. A simultaneous fit to the decay time difference distributions for opposite- and same-sign dilepton events gives $\Delta m_d = 0.493 \pm 0.012{(stat)}\pm 0.009{(syst)}$ ps$^{-1}$.Comment: 7 pages, 1 figure, submitted to Physical Review Letter

Functional characterization of the EMCV IRES in plants

The translation of eukaryotic messenger RNA is typically dependent upon the presence of an mGpppN cap structure at the 5' end of the transcript. However, several animal viruses, including the Picorna viruses, have been shown to exhibit cap-independent translation through the presence of an internal ribosome entry site or IRES. This IRES-mediated cap-independent internal translation initiation has been exploited to generate bicistronic transcripts that function in animal cells. Recently IRES elements have also been identified in a small number of vertebrate, insect and yeast cellular messenger RNAs although no such sequences have been identified in endogenous plant genes and there are no reports of animal virus derived IRES activity in plant cells. Here we have constructed a bicistronic gene containing both green fluorescent protein and luciferase open-reading frames separated by the encephalomyocarditis IRES element under the control of the CaMV 35S promoter. Northern analysis reveals expression of the bicistronic transcript and in vivo imaging of GFP and luciferase activities demonstrates the functional presence of both proteins. Western blot analysis confirms the independent translation of both reporter proteins. These data suggest that insertion of the encephalomyocarditis virus (EMCV) IRES element between two open-reading frames of a plant bicistronic transcript can mediate translation of the second open-reading frame. This activity is more apparent in the leaves, than in the roots, of transgenic seedlings carrying the bicistronic reporter gene construct

The first year of the BABAR experiment at PEP-II

The BABAR detector, situated at the SLAC PEP-II asymmetric e^+e^- collider, has been recording data at energies on and around the Upsilon(4S) resonance since May 1999. In this paper, we briefly describe the PEP-II B Factory and the BABAR detector. The performance presently achieved by the experiment in the areas of tracking, vertexing, calorimetry and particle identification is reviewed. Analysis concepts that are used in the various papers submitted to this conference are also discussed

Measurement of the time dependence of B0−Bˉ0B^{0}-\bar B^{0} oscillations using inclusive dilepton events

A preliminary study of time dependence of B^0-anti-B^0 oscillations using dilepton events is presented. The flavor of the B meson is determined by the charge sign of the lepton. To separate signal leptons from cascade and fake leptons we have used a method which combines several discriminating variables in a neural network. The time evolution of the oscillations is studied by reconstructing the time difference between the decays of the B mesons produced by the Y(4S) decay. With an integrated luminosity of 7.7 fb-1 collected on resonance by BABAR at the PEP-II asymmetric B Factory, we measure the difference in mass of the neutral B eigenstates, Delta_mB0 to be (0.507+/-0.015+/-0.022) x 10^{12} hbar-s^{-1}