|Title||Assessment of methylation level prediction accuracy in methyl-DNA immunoprecipitation and sodium bisulfite based microarray platforms.|
|Publication Type||Journal Article|
|Year of Publication||2011|
|Authors||Rajendram, R., J. Carlos Ferreira, D. Grafodatskaya, S. Choufani, T. Chiang, S. Pu, D. T. Butcher, S. J. Wodak, and R. Weksberg|
|Date Published||2011 Apr|
|Keywords||CpG Islands, DNA Methylation, Humans, Immunoprecipitation, Oligonucleotide Array Sequence Analysis, Sequence Analysis, DNA, Sulfates|
In this study, we verified the accuracy of two array methods--methylated DNA immunoprecipitation coupled with CpG island microarrays (MeDIP-CGI-arrays) and sodium bisulfite conversion based microarrays (BC-arrays)--in predicting regional methylation levels as measured by pyrosequencing of bisulfite converted DNA (BC-pyrosequencing). To test the accuracy of these methods we used the Agilent Human CpG island and the Illumina HumanMethylation27 microarrays respectively, and compared microarray outputs to the data from targeted BC-pyrosequencing assays from several genomic regions of corresponding samples. We observed relatively high correlation with BC-pyrosequencing data for both array platforms, R = 0.87 for BC-Array and R = 0.79 for MeDIP-CGI array. However, MeDIP-CGI array were less reliable in predicting intermediate levels of DNA methylation. Several bioinformatics strategies, to ameliorate the performance of the MeDIP-CGI-Arrays did not improve the correlation with BC-pyrosequencing data. The high scalability, low cost and simpler analysis of BC-arrays, together with the recent extended coverage may make them a more versatile methylation analysis tool.