The invention provides a method for detecting a target nucleotide sequence by tagging the nucleotide sequence with a nucleotide tag, providing a probe oligonucleotide with a melting temperature Tm1, comprising a regulatory sequence and a nucleotide tag recognition sequence; incorporating the probe oligonucleotide into the tagged polynucleotide in a polynucleotide amplification reaction, providing a regulatory oligonucleotide with a melting temperature Tm2, comprising a sequence segment that complementary to the regulatory sequence and a tail segment that does not hybridize to the probe nucleotide when the sequence segment and the regulatory sequence are annealed, amplifying the tagged target nucleic acid sequence in a PCR amplification reaction using the probe oligonucleotide as a primer, and using a DNA polymerase with high strand displacement activity and low 5′-nuclease activity, and detecting the amplification product; wherein Tm1 and Tm2 are higher than the annealing temperature associated with the polynucleotide amplification reaction.