Microarray RNA extraction - (Jul/21/2008 )

Hallo everybody,
I am doing microarray RNA extraction with a very good cell count but I found for actual microarray quality RNA I should give a Optimized DNAse treatment,but I am confused in which step shall I give DNase treatment can anybody has anything to say about it.Think before answaring because I am an experienced person so dont give Rubbish answar.

My steps were
1. Isolate RNA
2. Clean it up using Qiagen kit
3. DNase treatment
4. Follow Affymetrix protocol for labeling

Hope this helps.

First isolate RNA then give DNAse treatment and finaly purifiy RNA using Qiagen column chromatography. Same things i also using for my microarray experiments.
But i using Trizol methods in some sample after RNA isolation i purified RNA using RNesy Purification kit after purification no need to DNase digestion (confirmed by running QC samples on bioanalyzer for quality checking)