What is the recommended protocol for selecting endogenous controls? How should I choose an endogenous control?
Choosing which endogenous controls to use for normalization of real-time PCR experiments on microRNAs is not trivial. The most important feature of good controls is that expression levels be stable across the entire experimental design. In addition, it is important that the controls chosen have similar properties to microRNA in terms of purification yield. Therefore, small RNA molecules such as small nuclear or nucleolar RNAs are often used as endogenous controls for microRNA expression. Exiqon supply a number of miRCURY LNA™ Endogenous control primer sets based on small RNA molecules, please click here for details. Using stably expressed microRNAs as endogenous controls is also a very good option if it is possible to identify such controls within the experimental system. Two publications describe the testing of microRNAs as endogenous controls (see references below). Regardless of which endogenous controls are considered, it is critical that the controls are validated as being stable
