All oligonucleotides were synthesized by the Integrated DNA Technologies Inc. (Coralville, IA).
The PCR products were identified by gel electrophoresis and a UV transilluminator after purification.
After PCR amplification, the PCR product was purified by PCR purification kits (QIAquick;
QIAgen, Valencia, CA) and diluted serially with distilled water.