Unmethylated CpG motifs are prevalent in bacterial but not vertebrate genomic DNAs. Oligodeoxynucleotides (ODN) containing CpG motifs activate host defense mechanisms leading to innate and acquired immune responses. The recognition of CpG motifs requires Toll-like receptor (TLR) 9, which triggers alterations in cellular redox balance and the induction of cell signaling pathways including the mitogen activated protein kinases (MAPKs) and NF kappa B. Cells that express TLR-9, which include plasmacytoid dendritic cells (PDCs) and B cells, produce Th1-like proinflammatory cytokines, interferons, and chemokines. Certain CpG motifs (CpG-A) are especially potent at activating NK cells and inducing IFN-alpha production by PDCs, while other motifs (CpG-B) are especially potent B cell activators. CpG-induced activation of innate immunity protects against lethal challenge with a wide variety of pathogens, and has therapeutic activity in murine models of cancer and allergy. CpG ODN also enhance the development of acquired immune responses for prophylactic and therapeutic vaccination.

CpG Motifs in Bacterial DNA and Their Immune Effects

RNA interference (RNAi) holds considerable promise as a therapeutic approach to silence disease-causing genes, particularly those that encode so-called 'non-druggable' targets that are not amenable to conventional therapeutics such as small molecules, proteins, or monoclonal antibodies. The main obstacle to achieving in vivo gene silencing by RNAi technologies is delivery. Here we show that chemically modified short interfering RNAs (siRNAs) can silence an endogenous gene encoding apolipoprotein B (apoB) after intravenous injection in mice. Administration of chemically modified siRNAs resulted in silencing of the apoB messenger RNA in liver and jejunum, decreased plasma levels of apoB protein, and reduced total cholesterol. We also show that these siRNAs can silence human apoB in a transgenic mouse model. In our in vivo study, the mechanism of action for the siRNAs was proven to occur through RNAi-mediated mRNA degradation, and we determined that cleavage of the apoB mRNA occurred specifically at the predicted site. These findings demonstrate the therapeutic potential of siRNAs for the treatment of disease.

Therapeutic silencing of an endogenous gene by systemic administration of modified siRNAs

Construction of improved M13 vectors using oligodeoxynucleotide-directed mutagenesis.

III. Foldamer Research 3910 A. Overview 3910 B. Motivation 3910 C. Methods 3910 D. General Scope 3912 IV. Peptidomimetic Foldamers 3912 A. The R-Peptide Family 3913 1. Peptoids 3913 2. N,N-Linked Oligoureas 3914 3. Oligopyrrolinones 3915 4. Oxazolidin-2-ones 3916 5. Azatides and Azapeptides 3916 B. The â-Peptide Family 3917 1. â-Peptide Foldamers 3917 2. R-Aminoxy Acids 3937 3. Sulfur-Containing â-Peptide Analogues 3937 4. Hydrazino Peptides 3938 C. The γ-Peptide Family 3938 1. γ-Peptide Foldamers 3938 2. Other Members of the γ-Peptide Family 3941 D. The δ-Peptide Family 3941 1. Alkene-Based δ-Amino Acids 3941 2. Carbopeptoids 3941 V. Single-Stranded Abiotic Foldamers 3944 A. Overview 3944 B. Backbones Utilizing Bipyridine Segments 3944 1. Pyridine−Pyrimidines 3944 2. Pyridine−Pyrimidines with Hydrazal Linkers 3945

A field guide to foldamers.

The partial amino-acid sequence of purified human transforming growth factor-beta (TGF-beta) was used to identify a series of cDNA clones encoding the protein. The cDNA sequence indicates that the 112-amino acid monomeric form of the natural TGF-beta homodimer is derived proteolytically from a much longer precursor polypeptide which may be secreted. TGF-beta messenger RNA is synthesized in various normal and transformed cells.

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Human transforming growth factor-beta complementary DNA sequence and expression in normal and transformed cells.

On the basis of modeling studies, the (2-deoxy-α- and β-d-erythro-pentofuranosyl) (thymin-1-yl) alkanes 1a,b and 2a,b were selected as potential conformational probes for altDNA oligonucleotides. A straightforward approach to the synthesis of 1a,b and 2a,b from commercial 2-deoxy-d-ribose (3) and 1-O-methyl-2-deoxy-3,5-di-O-p-toluoyl-d-erythro-pentofuranose (13), respectively, was developed. These nucleoside analogues were converted to the phosphoramidite derivatives 27a,b−30a,b and incorporated into oligonucleotide 31 at predetermined sites and defined internucleotidic motifs. The insertion of 1a,b according to either a (3‘ → 5‘)- or a (3‘ → 3‘)-internucleotidic polarity produced oligonucleotides exhibiting a slightly higher affinity for their complementary unmodified DNA sequence than for the corresponding RNA sequence (Table 3). Conversely, the incorporation of 2a into 31 according to a (3‘ → 3‘)-orientation generated, for the first time, an altDNA oligonucleotide displaying a greater affinity for its ...

Synthesis of (2-deoxy-alpha - and -beta -d-erythro-pentofuranosyl)(thymin-1-yl)alkanes and their incorporation into oligodeoxyribonucleotides. effect of nucleobase-sugar linker flexibility on the formation of dna-dna and dna- rna hybrids

The Synthesis of Modified Oligonucleotides by the Phosphoramidite Approach and Their Applications

The Functionalization of Oligonucleotides via Phosphoramidite Derivatives

The discovery of deoxyribonucleoside cyclic N-acylphosphoramidites, a novel class of phosphoramidite monomers for solid-phase oligonucleotide synthesis, has led to the development of a number of phosphate protecting groups that can be cleaved from DNA oligonucleotides under thermolytic neutral conditions. These include the 2-(N-formyl-N-methyl)aminoethyl, 4-oxopentyl, 3-(N-tert-butyl)carboxamido-1-propyl, 3-(2-pyridyl)-1-propyl, 2-[N-methyl-N-(2-pyridyl)]aminoethyl, and 4-methythiobutyl groups. When used for 5′-hydroxyl protection of nucleosides, the analogous 1-phenyl-2-[N-methyl-N-(2-pyridyl)]aminoethyloxycarbonyl group exhibited excellent thermolytic properties, which may permit an iterative “heat-driven” synthesis of DNA oligonucleotides on microarrays. In this regard, progress has been made toward the use of deoxyribonucleoside cyclic N-acylphosphoramidites in solid-phase oligonucleotide syntheses without nucleobase protection. Given that deoxyribonucleoside cyclic N-acylphosphoramidites produce oligonucleotides with heat-sensitive phosphate protecting groups, blocking the 5′-hydroxyl of these monomers with, for example, the thermolabile 1-phenyl-2-[N-methyl-N-(2-pyridyl)]aminoethyloxycarbonyl group may provide a convenient thermo-controlled method for the synthesis of oligonucleotides on microarrays.

Conceptual "Heat-Driven" approach to the synthesis of DNA oligonucleotides on microarrays.

hosphoramidite compounds which are derivatives of saturated secondary amines and are used in the production of oligonucleotides.

Serge L. Beaucage

Papers

Synthesis of (2-deoxy-alpha - and -beta -d-erythro-pentofuranosyl)(thymin-1-yl)alkanes and their incorporation into oligodeoxyribonucleotides. effect of nucleobase-sugar linker flexibility on the formation of dna-dna and dna- rna hybrids

The Synthesis of Modified Oligonucleotides by the Phosphoramidite Approach and Their Applications

The Functionalization of Oligonucleotides via Phosphoramidite Derivatives

Conceptual "Heat-Driven" approach to the synthesis of DNA oligonucleotides on microarrays.

Phosphoramidite compounds and their use in producing oligonucleotides