Data evaluation II MDR1 CpG methylation as quantified by qPCR

As expected, CpG methylation levels within the BstU I sites did not fit into a normal distribution (P <0.01 for all Kolmogorov-Smirnov normality tests). For the 75 samples tested for promoter fragment 1 (MDR1-PCR 1), the ratios of BstU I-resistant DNA to total input DNA ranged from 0.00 to 0.40, with an inter-quartile range of 3% to 9%, implying that the target sequence is hypomethylated. Despite the suspicion that HIV-1 infection can induce DNA methylation (Mikovits et al., 1998, Fang et al., 2001), stratified analyses did not suggest that MDR1 methylation was elevated in HIV-1 seropositive individuals (P >0.20). Results for the intron 1 region

Ratio of BstU 1-resistant DNA to total DNA (test 1)

Figure 10.2

Ratio of BstU 1-resistant DNA to total DNA (test 1)

Figure 10.2

Close correlation of qPCR results obtained from different experiments. At intervals ranging from one week to three months, genomic DNA samples (n = 75) treated with the methylation-sensitive endonuclease BstU I were tested twice for the MDR1 promoter (panel a) and intron 1 (panel b) sequence, which has one and six BstU I (CGCG) sites, respectively (see Table 2 for technical details). Samples from females (F) and males (M) are labeled separately.

(inter-quartile range, 1% to 5%) are similiar, although the assay only measured sequences in which all six BstU I sites are resistant to digestion. Additional qPCR assays and pyrosequencing confirmed the hypomethyla-tion status of multiple CpG sites at the MDR1 locus.

0 0

Post a comment