Effect of miRNA preparations on reverse transcription (RT)-PCR for kallikrein 1b26 (klk1b26) mRNA. (A,B) Effect of miRNA preparation on the PCR product formation. RT-PCR was performed with the F21/R552 primer pair targeting the 5'-terminal region of klk1b26 mRNA (A) or with the F169/R552 primer pair targeting the middle region of the mRNA (B) in the presence of the indicated concentrations of miRNA prepared from either male or female submandibular glands (SMGs). Representative results are shown, and similar results were obtained in three independent experiments. (C) Effect of female miRNA preparation on the PCR product formation using various forward primers targeting the 5'-terminal region. PCR was carried out with each forward primer in combination with the R552 reverse primer in the absence (-) or presence (+) of miRNAs prepared from female SMGs (10 ng/μl). Sequences of the primers used are indicated in Table 1. Representative results are shown. Similar results were obtained in three independent experiments.