Fig. 4.
Nested RT-PCR amplification using 10-fold serial dilutions of plasmid DNA. Plasmid DNAs containing (A) bcr1, (B) bcr2, and (C) bcr3 sequences (starting amounts: 8.8 × 108, 7.8 × 108, and 8.0 × 108 copies/tube, respectively) were diluted by the indicated DF and amplified by nested RT-PCR. Amplification products were separated by 1.5% agarose gel electrophoresis (100 V, 35 min). DF, dilution factor; DW, distilled water; M, 100-bp ladder size marker; RT-PCR, reverse transcription polymerase chain reaction.