A comparison of RNA amplification techniques at sub-nanogram input concentration.

Area of Science:

• Molecular Biology
• Genomics
• Biotechnology

Background:

• Gene expression profiling necessitates high-fidelity RNA amplification, especially for limited cell quantities.
• Accuracy of RNA amplification methods with very low-input RNA (sub-nanogram) is critical for rare clinical samples.
• Existing amplification methods have had limited evaluation for low-input RNA accuracy.

Purpose of the Study:

• To compare the accuracy of different RNA amplification techniques for gene expression profiling using low-input quantities.
• To evaluate modified T7, Arcturus RiboAmp HS (linear amplification), and Balanced PCR (logarithmic amplification).
• To validate microarray data against quantitative real-time PCR (QPCR).

Main Methods:

• Comparison of three RNA amplification methods: modified T7, Arcturus RiboAmp HS, and Balanced PCR.
• Starting RNA quantities ranged from 250 picograms to 3.3 nanograms.
• Microarray data validation using quantitative real-time PCR (QPCR) for 37 genes.

Main Results:

• High-intensity spots showed acceptable Pearson correlations across all amplification methods and RNA inputs.
• Microarray data processing significantly impacts correlation coefficients.
• While unfiltered total RNA arrays showed higher correlations, amplified arrays of high-intensity genes demonstrated superior correlations.

Conclusions:

• Gene expression arrays are feasible with sub-nanogram RNA input.
• QPCR validation confirms the accuracy of gene expression profiling from low-input RNA across all tested amplification methods.
• Accurate sub-nanogram RNA analysis is achievable using data processing for high-intensity genes or QPCR validation.