A variety of different tiles for the construction of DNA lattices have been developed since the structural DNA nanotechnology field was born. The majority of these are designed for the realization of close-packed structures, where DNA helices are arranged in parallel and tiles are connected through sticky ends. Assembly of such structures requires the use of cation-rich buffers to minimize repulsion between parallel helices, which poses limits to the application of DNA nanostructures. Wireframe structures, on the other hand, are less susceptible to salt concentration, but the assembly of wireframe lattices is limited by the availability of tiles and motifs. Herein, we report the construction of a polyhedral 12-arm junction for the self-assembly of wireframe DNA lattices. Our approach differs from traditional assembly of DNA tiles through hybridization of sticky ends. Instead, the assembly approach presented here uses small polyhedral shapes as connecting points and branch points of wires in a lattice structure. Using this design principle and characterization techniques, such as transmission electron microscopy, single-particle reconstruction, patterning of gold nanoparticles, dynamic light scattering, UV melting analyses, and small-angle X-ray scattering among others, we demonstrated formation of finite 12-way junction structures, as well as 1D and 2D short assemblies, demonstrating an alternative way of designing polyhedral structures and lattices.

Disulfide dithymidines linked 3'-5' or 3'-6' were synthesized and incorporated into oligonucleotides through a combined phosphotriester and phosphoramidite solid-phase oligonucleotide synthesis approach. The disulfide links are cleaved and formed reversibly in the presence of thiols and oligonucleotides. This link was shown to be sequence-adaptive in response to given templates in the presence of mercaptoethanol. The artificial 3'-5' and 3'-6' disulfide link was tolerated by polymerases in the polymerase chain reaction (PCR). By using sequencing analysis, we show that single mutations frequently occurred randomly in the amplification products of the PCR.

Triplex forming oligonucleotides are used as a tool for gene regulation and in DNA nanotechnology. By incorporating artificial nucleica cids, target affinity and biological stabilitys uperior to that of naturalD NA mayb e obtained. This work demonstrates how ac himeric clamp consisting of acyclic( L)-threoninol nucleic acid (aTNA) and DNA can bind DNA and RNA by the formationof ah ighly stable triplex structure. The (L)-aTNA clamp is released from the targeta gain by the addition of ar eleasing strand in as trand displacement type of reaction. It is shown that the clamp efficientlyi nhibits Bsu and T7 RNA polymerase activity and that polymerase activity is reactivated by displacing the clamp. The clamp was successfully appliedt o the regulation of luciferase expression by reversible binding to the mRNA. When targeting as equence in the double stranded plasmid, 40 %d ownregulation of protein expression is achieved.[a] Dr.

A gene was obtained from 14 oligonucleotides self-assembled and chemically ligated in a DNA nanostructure.