We used the RNeasy ® Mini Kit

both the expression level of a specific messenger RNA (mRNA) and the expression level of the cognate protein. Methods that allow the isolation of both from the same experimental sample reduce effort and make the interpretation of experimental results simpler. Many researchers isolate total RNA quickly and efficiently using column-based kits that do not require hazardous chemicals such as phenol or chloroform or time-consuming CsCl gradient centrifugation (1). The denaturing properties of guanidine salts and 2-mercaptoethanol inhibit RNA degradation, and the charged column matrices allow the binding and subsequent elution of total RNA pure enough for microarray analysis, cDNA generation, reverse transcription PCR (RT-PCR), or Northern blot analysis. Here we show that it is possible to also isolate protein for use in immunoblots from a sample processed for total RNA using these column-based kits