RNA and protein clean‐up from the same specimen. Comparison between the Qiagen and Ambion protocols

Study of gene and protein expression patterns is considered desirable for gaining new insight into cellular molecular mechanisms. The purpose of the present study was to compare the RNeasy (Qiagen) and PARIS (Ambion) protocols for protein and RNA clean‐up. We found that the RNeasy protocol resulted in a significantly higher yield of both RNA and protein compared to the PARIS protocol. Western blot analysis of proteins isolated with these two methods, and with use of three different antibodies (PKB/Akt, c‐fos and CREM), indicated that these methods were equal in regard to protein patterns, despite the protein precipitation step that is included in the RNeasy protocol. In some cases, Western blot performed on unprecipitated flow‐through (Qiagen) may be satisfactory for Western blot analysis, but the amount of protein is probably decisive for detection.