Whole blood RNA and DNA extraction help - Expression analysis and epigenetics (Jun/07/2011 )
I need to extract RNA and DNA from very small samples(total volume 100 - 150 ul)of whole blood with downstream applications being qRT-PCR for expression analysis of specific genes, and DNA methylation analysis of specific genes via bisulfite treatment and pyrosequencing. Can anyone give me some recommendations for stabilizing the RNA at the time of sampling and compatible RNA and DNA purification methods?
You can isolate RNA and DNA (and protein) at he same time with Trizol-based chemistry. There is special version of Trizol/Trireagent that's suitable for blood, TRI ReagentBD from Sigma .
But RNA isolated from Trizol needs to be DNase treated for qPCR (but that's not specific to Trizol only) and there are some minor issues with DNA isolation, as it should be dissolved in 8mM NaOH instead of water, but this archived post describes using Trizol-izolated DNA for bisulfate treatment and not having problems with that.
You could get ~100 ng of RNA and ~5 ug of DNA from 100-150 ul of human whole blood using our AquaPreserve method. Here is the brief protocol http://www.aquaplasmid.com/AquaPreserve.html#protocol.