A simple and efficient method to reduce nontemplated nucleotide addition at the 3 ' terminus of RNAs transcribed by T7 RNA polymerase

DNA templates modified with C2'-methoxyls at the last two nucleotides of th e 5' termini dramatically reduced nontemplated nucleotide addition by the T 7 RNA polymerase from both single- and double-stranded DNA templates. This strategy was used to generate several different transcripts. Two of the tra nscripts were demonstrated by nuclear magnetic resonance spectroscopy to be unaffected in their sequence; Transcripts produced from the modified templ ates can be purified with greater ease and should,be useful in a number of applications.