Ly. Luo et Ep. Diamandis, Amplification of human genomic DNA sequences with polymerase chain reaction using a single oligonucleotide primer, J CL LAB AN, 13(2), 1999, pp. 69-74
We present two examples of exponential nucleic acid amplification with the
polymerase chain reaction (PCR) in the presence of only one amplification p
rimer. Cloning and sequencing of the PCR products generated by amplificatio
n of human genomic DNA revealed that the amplified sequence contained only
one primer and its complement, at the two ends of the PCR product. Although
these experiments were performed with primers derived from the sequence of
the prostate specific antigen (PSA) gene and the normal epithelial cell-sp
ecific 1 gene (NES1), the amplified sequences were novel and had no homolog
y with either PSA or NES1 DNA. While both PSA and NES1 genes reside on chro
mosome 19q13.3-q13.4, the amplified sequences were found by mapping to resi
de on chromosome 5q12 and 5p15.1-p15.3, respectively. When we examined the
mechanism of amplification by PCR using one primer in these two cases, we f
ound that there was a high homology between the PSA primer or the NES1 prim
er and the two regions flanking the amplified sequence of chromosome 5q12 o
r 5p15. This indicated that the single PSA or NES1 primer could anneal on b
oth strands of the DNA of that region, and mediate the exponential amplific
ation. Since this phenomenon occurred to us twice with a limited number of
different PCR reactions performed in our laboratory (< 20), we believe that
it may represent a common artifact of PCR. Moreover, it appears that the p
alindromic primer binding sites can anneal to each other forming DNA crucif
orms. J. Clin. Lab. Anal. 13:69-74, 1999. (C) 1999 Wiley-Liss, Inc.