Directional amplification of RNA

A process for directionally amplifying RNA, the process comprising:

• (a) reverse transcribing at least one RNA molecule in the presence of a plurality of first synthesis primers to generate a plurality of first strands of complementary DNA (cDNA), each of the first synthesis primers comprising a 3′ sequence having complementarity to a portion of the RNA molecule, a 5′ sequence corresponding to one or more methylated amplification primers, and optionally an internal tag sequence comprising a first tag sequence;
• (b) replicating the plurality of first strands of cDNA in the presence of a plurality of second synthesis primers to generate a plurality of double-stranded cDNA products, each of the second synthesis primers comprising a 3′ sequence having complementarity to a portion of the first strands of cDNA, a 5′ sequence corresponding to the one or more methylated amplification primers, and optionally an internal tag sequence comprising a second tag sequence, provided that either one or both of the pluralities of first and second synthesis primers comprises the internal tag sequence such that each double-stranded cDNA product is flanked by either the first or second tag sequence or both the first and second tag sequences;
• and
• (c) amplifying the plurality of double-stranded cDNA products in the presence of the one or more methylated amplification primers to generate an amplified library of cDNA products;
• wherein the 5′ sequence of the first and second synthesis primers further comprises at least one binding element for a methylation-dependent restriction enzyme, and
• wherein the amplified library of cDNA products is contacted with the methylation-dependent restriction enzyme.