239 results about "Phosphoramidite" patented technology

Oligonucleotide analogues are provided that incorporate 5-aza-cytosine in the oligonucleotide sequence, e.g., in the form of 5-aza-2′-deoxycytidine (decitabine) or 5-aza-cytidine. In particular, oligonucleotide analogues rich in decitabine-deoxyguanosine islets (DpG and GpD) are provided to target the CpG islets in the human genome, especially in the promoter regions of genes susceptible to aberrant hypermethylation. Such analogues can be used for modulation of DNA methylation, such as effective inhibition of methylation of cytosine at the C-5 position. Methods for synthesizing these oligonucleotide analogues and for modulating nucleic acid methylation are provided. Also provided are phosphoramidite building blocks for synthesizing the oligonucleotide analogues, methods for synthesizing, formulating and administering these compounds or compositions to treat conditions, such as cancer and hematological disorders.

Oligonucleotide chemistry is central to the advancement of core technologies such as DNA sequencing, forensic and genetic analysis and has impacted greatly on the discipline of molecular biology. Oligonucleotides and their analogues are essential tools in these areas. They are often produced by automated solid-phase phosphoramidite synthesis but it is difficult to synthesize long DNA and RNA sequences by this method. Methods are proposed for ligating oligonucleotides together, in particular the use of an azide-alkyne coupling reaction to ligate the backbones of oligonucleotides together to form longer oligonucleotides that can be synthesized using current phosphoramidite synthesis methods.

Novel technology for RNA synthesis in the reverse direction, involving a new class of products, 3′-DMT-5’-CE ribonucleoside phosphoramidites and 3′-DMT-5’-succinyl ribonucleoside solid supports, with per step coupling efficiency surpassing 99% in the RNA synthesis. This leads to high purity RNA. Examples of a large number of 20-21 mers and a few examples of long chain oligonucleotides are demonstrated. The data indicates dramatic improvement in coupling efficiency per step during oligonucleotide synthesis using the reverse RNA monomers (5′→′ direction) as compared to 3′-CE ribonucleoside phosphoramidites used in the conventional method of RNA synthesis (3′→5′ direction). The new process requires shorter coupling cycle time, approx. 4 minutes as compared to approx. 10 minutes using conventional RNA synthesis method (3′→5′ direction). Furthermore, almost complete absence of M+1 impurities in the reverse RNA synthesis methodology were observed, even when the last phosphoramidite was a macromolecule. The process resulted in very high purity 3′-modified oligonucleotides after HPLC purification. As a result of high purity of synthesized RNA and clean introduction of various 3′-end modified RNA requiring long chain ligands, chromophores, fluorophores and quenchers, this method of RNA synthesis is expected to be a very useful method of choice for therapeutic grade RNA. The novel phosphoramidites of this invention, Rev-A-n-bz, Rev-C-n-bz, Rev-C-n-ac, Rev-G-n-ac and Rev-rU show HPLC purity greater than 98% and 31P NMR purity greater than 99.5%.

Methods of synthesizing oligonucleotides with high coupling efficiency (>99.5%) are provided. Methods for purification of synthetic oligonucleotides are also provided. Instrumentation configurations for oligonucleotide synthesis are also provided. Methods of designing and synthesizing polynucleotides are also provided. Polynucleotide design is optimized for subsequent assembly from shorter oligonucleotides. Modifications of phosphoramidite chemistry to improve the subsequent assembly of polynucleotides are provided. The design process also incorporates codon biases into polynucleotides that favor expression in defined hosts. Design and assembly methods are also provided for the efficient synthesis of sets of polynucleotide variants. Software to automate the design and assembly process is also provided.

The present invention relates to compositions and methods for the preparation of modified nucleic acids. In particular, the present invention provides novel reagents and chemistries for the generation of linkers, modified phosphoramidites, and modified solid supports.