Abstract: Objective P16 CpG island targeted short interfering RNAs (siRNAs) were designed to analyze whether RNA-directed DNA methylation (RdDM) functions in formation of P16 methylation in mammalian cells. Methods BGC823 cells were transduced with siRNAs targeted to promoter and exon1 region of P16, respectively. Semi-quantitative RT-PCR and western blot were used for P16 expression detection. DNA methylation statuses were also analyzed with methylation specific PCR (MSP) and bisulfite clone sequencing. Results The promoter and exon1 targeted siRNAs could decrease P16 expression. Nevertheless, both siRNAs could not induce methylation of targeted DNA. Conclusions The present data indicates that siRNAs can not down-regulate P16 gene expression through inducing DNA methylation in BGC823 cell line.

Key words: CpG island, RNA-directed DNA Methylation, siRNA, p16, methylation