Enzymatic fabrication of high-density RNA arrays

A powerful new strategy for the fabrication of high-density RNA arrays is described. A high-density DNA array is fabricated by standard photolithographic methods, the surface-bound DNA molecules are enzymatically copied into their RNA complements from a surface-bound RNA primer, and the DNA templates are enzymatically destroyed, leaving behind the desired RNA array. The strategy is compatible with 2'-fluoro-modified (2'F) ribonucleoside triphosphates (rNTPs), which may be included in the polymerase extension reaction to impart nuclease resistance and other desirable characteristics to the synthesized RNAs. The use and fidelity of the arrays are explored with DNA hybridization, DNAzyme cleavage, and nuclease digestion experiments.