Determination of RNA Structure with In Vitro SHAPE Experiments.

Area of Science:

• Molecular Biology
• Biochemistry
• Structural Biology

Background:

• RNA secondary structure is crucial for function, regulation, and translation.
• In silico RNA structure prediction is less accurate for long RNAs and high temperatures, necessitating experimental validation.
• Selective 2 -hydroxyl acylation analyzed by primer extension (SHAPE) is a key technique for mapping RNA structure in vitro and in vivo.

Purpose of the Study:

• To describe a detailed protocol for an in vitro SHAPE experiment for RNA structure analysis.
• To validate and enhance the accuracy of in silico RNA secondary structure predictions using experimental data.
• To provide a method for identifying single-stranded nucleotides within RNA molecules.

Main Methods:

• In vitro transcription of RNA using a T7 polymerase system.
• RNA folding and subsequent modification with N-methyl isatoic anhydride (NMIA), a SHAPE reagent.
• Primer extension using a radioactive 32P-labeled primer, followed by denaturing acrylamide gel electrophoresis and autoradiography to detect reverse transcriptase stops.

Main Results:

• The protocol successfully identifies single-stranded nucleotides in RNA through SHAPE modifications and reverse transcription stops.
• Quantification of reverse transcription stops and NMIA-modification efficiencies using ImageJ software.
• Experimental data obtained can be used to validate and improve computational RNA secondary structure predictions.

Conclusions:

• The described in vitro SHAPE protocol provides a robust method for experimental RNA structure determination.
• This technique is valuable for validating and refining in silico RNA secondary structure models.
• Accurate RNA structure mapping is essential for understanding RNA function and regulation.