Base Invaders

The standard approach for extraction of poly(A)⁺ RNA from cell lysates is by oligo(dT) cellulose affinity chromatography. However, recent advances in peptide nucleic acid chemistry have produced another method for poly(A)⁺ RNA extraction. This novel technology uses phosphono-peptide nucleic acids (pPNA). These molecules are similar to DNA except A, T, G, or C bases are covalently attached to an N-(2-aminoethyl) glycine backbone.¹ Water-soluble pPNAs hybridize to both DNA and RNA but are not degraded by nucleases or peptidases.

Active Motif of Carlsbad, Calif., now offers mVADER, the first commercially available kit that utilizes biotinylated oligo(T) pPNA to capture poly(A)⁺ RNA. One of the strengths of the system, according to Dorothy Phelan, senior scientist at Active Motif, is that the invasive clamping pPNAs can bind to mRNA molecules that contain extensive secondary structure and form stable complexes with shorter poly(A) tails than does oligo(dT) cellulose....