RT-Bst: an integrated approach for reverse transcription and enrichment of cDNA from viral RNA.

The synthesis of cDNA from RNA is challenging due to the inefficiency of reverse transcription (RT). In order to address this, an RT-Bst method was developed for sequential RT of RNA and Bst DNA polymerase amplification for enrichment of cDNA in a single-tube reaction. Using genomic RNA from bacteriophage MS2, the yield of cDNA produced by RT alone and RT-Bst were compared by analysis of polymerase chain reaction (PCR)-amplified products. A superior performance was observed when amplifying MS2 cDNA with random primers following RT-Bst compared to RT alone, indicating greater quantities of cDNA were present after RT-Bst. RT-Bst was also compared with RT alone for their relative ability to produce sufficient cDNA to amplify eight target regions spanning the respiratory syncytial virus (RSV) genome. Six out of eight targets were amplified consistently by PCR subsequent to RT-Bst amplification, whereas only three out of eight targets could be amplified after RT alone. The RSV sequences were selectively amplified using RSV-specific primers from a mixed template containing an excess of MS2 RNA without amplifying MS2 sequences. This suggests that RT-Bst can be used to amplify RNA sequences non-specifically using random primers and specifically using sequence-specific primers, and enhances the yield of cDNA when compared to RT alone.