Integrity assay for messenger RNA in mouse and human brain samples and synaptosomal preparations

Area of Science:

• Molecular Biology
• Genomics
• Biochemistry

Background:

• Traditional RNA integrity assessment relies on ribosomal RNAs (rRNAs), which are not the focus of gene expression studies.
• Messenger RNAs (mRNAs) are crucial for understanding gene expression, but their integrity is often overlooked.
• Existing methods may not be suitable for all sample types, such as subcellular preparations lacking rRNAs.

Purpose of the Study:

• To develop and validate a novel RT-qPCR assay for evaluating mRNA integrity.
• To assess the reliability of the assay across different degradation conditions and sample types.
• To provide a method for accurate mRNA integrity assessment in gene expression studies.

Main Methods:

• Development of a 5':3' RT-qPCR assay comparing the abundance of 3' and 5' mRNA fragments.
• Validation using plasmids with cloned cDNA ends to simulate varying RNA degradation levels.
• Quantification of RNA degradation in heat- and enzyme-treated mouse and human brain tissue RNA.
• Application of the assay to clinical human brain RNA and synaptosomal preparations.

Main Results:

• The 5':3' assay accurately estimates mRNA integrity by analyzing the ratio of 3' and 5' mRNA fragments.
• Primer efficiency was incorporated to ensure the accuracy of the integrity values.
• The assay successfully quantified RNA degradation in various degraded RNA samples, including mouse and human brain tissues.
• The method proved effective for assessing mRNA integrity in synaptosomal preparations, which are rRNA-deficient.

Conclusions:

• The developed 5':3' assay is a reliable and accurate method for evaluating mRNA integrity.
• This assay is suitable for a wide range of biological samples, including tissue and subcellular preparations.
• It offers a valuable tool for gene expression studies where mRNA quality is critical.