Plk4 CpG island methylation and expression levels in elderly Plk4
male mice and HCC samples. Shown in each case (a-c) is a representative figure of typical results based on determination of Plk4 promoter methylation in 6-9 females and males for both Plk4 wild type and Plk4
+/- genotypes. (a) Methylation status of Plk4 promoter regions of genomic DNA extracted from liver tumours in Plk4
+/-mice as determined by MSP. U = unmethylated, M = methylated. (b) Plk4 CpG island methylation of liver samples from mice aged 6 months and (c) 9 months. (d) Graphical representation summarizing percentage of Plk4 promoter methylation in liver tumours from 18-24 month old Plk4
+/-male mice. (e) Relative levels of Plk4 transcripts as determined by qPCR. RQ values were normalized to the level of Plk4 transcripts in livers from 9 months old Plk4
+/+animals. The error bars represent the upper and lower limit of the standard error from the mean expression level (RQ). (f) Relative levels of Plk4 transcripts in liver tissue and tumours from elderly mice. (g) Level of Plk4 protein in liver tissue extracts as determined by Western blot analysis. Actin levels were used as a loading control. N = normal tissue, T = tumour tissue.