RNA probes are usually prepared with biotin or specific fluorophore by in vitro transcription. High specific activity RNA probes or riboprobes are synthesized from DNA templates cloned in expression vectors such as SP6 and T7 systems. Biotin-labeled antisense RNA (aRNA) is generated from total cellular RNA samples with Enzo BIOARRAY Amplification and labeling systems (ENZ-42420, ENZ-42421, ENZ-42422).