Simultaneous DNA and RNA isolation from brain punches for epigenetics

BACKGROUND: Epigenetic modifications such as DNA methylation play an important role for gene expression and are regulated by developmental and environmental signals. DNA methylation typically occurs in a highly tissue- and cell-specific manner. This raises a severe challenge when studying discrete, small regions of the brain where cellular heterogeneity is high and tissue quantity limited. Because gene expression and methylation are often tightly linked it appears of interest to compare both parameters in the same sample. FINDINGS: We present a refined method for the simultaneous extraction of DNA for bisulfite sequencing and RNA for expression analysis from small mouse brain tissue punches. This method can also be easily adapted for other small tissues or cell populations. CONCLUSIONS: The method described herein results in DNA and RNA of a quantity and quality permitting highly reliable bisulfite analysis and quantitative RT-PCR measurements, respectively.