SP6 RNA-POLYMERASE EFFICIENTLY SYNTHESIZES RNA FROM SHORT DOUBLE-STRANDED DNA TEMPLATES

SP6 DNA-dependent RNA polymerase, like T7 RNA polymerase, can be used to synthesize RNA sequences from short DNA templates which contain the 1 8 base pair promoter region. Use of SP6 polymerase extends the rang e of possible 5' sequences of RNA products, since the preferred SP6 st art site (of the RNA product) is 5'GAAGA, while T7 polymerase prefers 5'GGGAG. The SP6 start site can be advantageous in large-scale synthes es where high concentrations of RNA can lead to aggregation. Using the limited number of DNA templates described here, there appears to be a significant difference between the two enzymes: SP6 polymerase requir es a complete duplex DNA substrate for efficient synthesis, unlike the T7 enzyme which works efficiently when only the 18 base promoter regi on is double-stranded. SP6 polymerase consistently produces higher yie lds of RNA than does T7 polymerase, and the reactions can be easily sc aled up to produce milligram quantities of RNA.