Thursday, June 26, 2025

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Beyond the Nanodrop: A Game-Changing Method for RNA Purity

 Using pfALBA3 to Check for Genomic DNA Contamination in Plasmodium RNA Extractions


When working with Plasmodium falciparum, extracting high-quality RNA is crucial for downstream applications like qRT-PCR, transcriptomics, and gene expression analysis. However, one common challenge is genomic DNA (gDNA) contamination in RNA samples—which can lead to false positives or skewed expression data.

To tackle this issue, researchers often use a control gene to confirm whether RNA samples are truly free from DNA contamination. One such reliable control is the Plasmodium falciparum gene pfALBA3 (gene ID: PF3D7_1006200).

 What is pfALBA3?

pfALBA3 belongs to the ALBA (Acetylation Lowers Binding Affinity) family of RNA-binding proteins. In P. falciparum, ALBA proteins are thought to play key roles in:

  • RNA metabolism and regulation

  • Stage-specific gene expression

  • Possibly even translational control during the parasite's complex lifecycle

Because pfALBA3 is consistently transcribed in blood-stage parasites, it serves as a stable internal reference gene—a feature that makes it ideal for use in RNA quality control assays.


How pfALBA3 Detects DNA Contamination

The typical approach involves using primers that span exon-exon junctions in the pfALBA3 mRNA transcript. Here's how it works:

Condition

Result

Interpretation

RT-PCR (+ reverse transcriptase)

Amplification

Confirms presence of pfALBA3 mRNA

PCR (– reverse transcriptase)

No amplification

No gDNA contamination present

PCR (– RT) but amplification occurs

Indicates gDNA contamination


By comparing reactions with and without reverse transcriptase (RT), you can easily tell whether your RNA sample is clean. If the –RT control yields no amplification of pfALBA3, you're in the clear.


Why pfALBA3 Works Well

  • Exon-spanning primers reduce the chance of gDNA amplification.

  • Abundant expression makes it easy to detect in RNA samples.

  • It’s a housekeeping gene, so expression is relatively stable across lifecycle stages.

This makes pfALBA3 not just a marker of RNA integrity, but also a reliable check for DNA-free extractions—a must for high-confidence transcriptomics.


Best Practices

  • Always include a –RT control when using pfALBA3 in qPCR.

  • Perform DNase treatment after RNA extraction to remove any residual gDNA.

  • Run a no-template control (NTC) to check for primer-dimer or environmental contamination.


Conclusion

Using pfALBA3 as a sentinel gene for RNA quality is a smart move when working with Plasmodium falciparum. It enables you to detect and eliminate gDNA contamination early—saving time, resources, and the integrity of your gene expression data.


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Adwoa Agyapomaa has a BSc from RMIT, Australia and an MPH from Monash University, Australia. Adwoa is the founder of Adwoa Biotech. She is currently a Senior Research Assistant. Enjoyed the tutorial? Connect with me on YouTube [Adwoa Biotech] where we talk biotech techniques, and lab workflows.