mRNA expression of DNA methyltransferases and methyl-CpG-binding proteins may not be associated with IRF-4 promoter methylation
Since abundance of DNMT and MBP contribute to promoter regulation via methylation (25,26,28), we studied their mRNA expression to investigate a possible mechanism for the observed methylation differences in the IRF-4 promoter. To this end, we did not detect a significant difference in DNMT (DNMT1, DNMT3A and DNMT3B) or MBP (MBD1, MBD2, MBD4 and MeCP) mRNA expression between IRF-4-positive and -negative cells (Figure 5D). In fact, all analyzed cells had moderate to high mRNA levels of these tested DNMT/MBPs and differences in expression were not correlated with IRF-4 status. These results indicate a distinct cause of the methylation differences in IRF-4-positive and -negative cells rather than changes in the DNMT and MBP mRNA transcription. 
