title: The methylation status of plant genomic DNA influences PCR efficiency.
abstract: During the polymerase chain reaction (PCR), which is a versatile and widely used method, certain DNA sequences are rapidly amplified through thermocycling. Although there are numerous protocols of PCR optimization for different applications, little is known about the effect of DNA modifications, such as DNA methylation, on PCR efficiency. Recent studies show that cytosine methylation alters DNA mechanical properties and suggest that DNA methylation may directly or indirectly influence the effectiveness of DNA amplification during PCR. In the present study, using plant DNA, we found that highly methylated plant DNA genomic regions were amplified with lower efficiencies compared to that for the regions methylated at a lower level. The correlation was observed when amplifying stilbene synthase (STS1, STS10) genes of Vitis amurensis, the Actin2 gene of Arabidopsis thaliana, the internal transcribed spacer (AtITS), and tRNAPro of A. thaliana. The level of DNA methylation within the analyzed DNA regions has been analyzed with bisulfite sequencing. The obtained data show that efficient PCRs of highly methylated plant DNA regions can be hampered. Proteinase K treatment of the plant DNA prior to PCR and using HotTaq DNA polymerase improved amplification of the highly methylated plant DNA regions. We suggest that increased DNA denaturation temperatures of the highly methylated DNA and contamination with DNA-binding proteins contribute to the hampered PCR amplification of highly methylated DNA. The data show that it is necessary to use current DNA purification protocols and commercial kits with caution to ensure appropriate PCR product yield and prevent bias toward unmethylated DNA amplification in PCRs.
authors.affiliation: Laboratory of Biotechnology, Institute of Biology and Soil Science, Far East Branch of Russian Academy of Sciences, Vladivostok 690022, Russia; Department of Biochemistry, Microbiology and Biotechnology, The School of Natural Sciences, Far Eastern Federal University, 690090, Vladivostok, Russia. Electronic address: kiselev@biosoil.ru.
authors.forename: K V
authors.initials: KV
authors.lastname: Kiselev
authors.affiliation: Laboratory of Biotechnology, Institute of Biology and Soil Science, Far East Branch of Russian Academy of Sciences, Vladivostok 690022, Russia.
authors.forename: A S
authors.initials: AS
authors.lastname: Dubrovina
authors.affiliation: Laboratory of Biotechnology, Institute of Biology and Soil Science, Far East Branch of Russian Academy of Sciences, Vladivostok 690022, Russia.
authors.forename: A P
authors.initials: AP
authors.lastname: Tyunin
mesh_terms: D000217:Acyltransferases / Q000235:genetics*; D017360:Arabidopsis / Q000235:genetics*; D019175:DNA Methylation; D018744:DNA, Plant / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D010940:Plant Proteins / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods*; D027843:Vitis / Q000235:genetics*
chemical_list: D018744:DNA, Plant; D010940:Plant Proteins; D000217:Acyltransferases; C022674:stilbene synthase
keywords: Arabidopsis thaliana; HotTaq DNA polymerase; Plant DNA extraction; Proteinase K; Vitis amurensis