RNA isolation
Total RNA from mouse MSCs, which using growth factor induction to the neuronal differentiation was extracted by using the TRI reagent (Molecular Research Center, Inc.; see appendix C). Reverse transcription was performed by using ThermoScriptTMRT-PCR System (Invitrogen) and identified genes expression by PCR was performed by using Platinum®Taq DNA Polymerase. Total RNA were extracted by RNeasy mini kit (Qiagen, Chatworth, CA, USA) according to the instruction of manufacturer. The kit combines the selective binding properties of a silica-based membrane with the speed of microspin technology. Briefly, kidney tissues were first lysed and homogenized in the presence of a highly denaturing guanidine-thiocyanate containing buffer, which immediately inactivates RNases to ensure purification of intact RNA. Ethanol was added to provide appropriate binding conditions, and the sample was then applied to an RNeasy Mini spin column, where the total RNA binds to the membrane and contaminants were efficiently washed away. High-quality RNA was then eluted in 35 ul water and stored at - 70o c.